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Extraterrestrial atmosphere

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For the view from an astronomical object's surface, seeExtraterrestrial sky.
Major features of the Solar System (not to scale)
Graphs of escape velocity against surface temperature of some Solar System objects showing which gases are retained. The objects are drawn to scale, and their data points are at the black dots in the middle.

The study ofextraterrestrial atmospheresis an active field of research,[1]both as an aspect of astronomy and to gain insight into Earth's atmosphere.[2]In addition to Earth, many of the otherastronomical objectsin theSolar Systemhaveatmospheres.These include all thegiant planets,as well asMars,VenusandTitan.Severalmoonsand other bodies also have atmospheres, as docometsand theSun.There is evidence thatextrasolar planetscan have an atmosphere. Comparisons of these atmospheres to one another and to Earth's atmosphere broaden our basic understanding of atmospheric processes such as thegreenhouse effect,aerosoland cloud physics, andatmospheric chemistryand dynamics.

In September 2022, astronomers were reported to have formed a new group, called "Categorizing Atmospheric Technosignatures"(CATS), to list the results ofexoplanetatmosphere studies forbiosignatures,technosignaturesand related.[3]

Planets

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Inner planets

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Earth is excluded from this enumeration because this article is about extraterrestrial atmospheres. For information about the terrestrial atmosphere, seeatmosphere of Earth.

Mercury

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Main article:Atmosphere of Mercury

Due to its small size (and thus its small gravity),Mercuryhas no substantial atmosphere. Its extremely thin atmosphere mostly consists of a small amount of helium and traces of sodium, potassium, and oxygen. These gases derive from thesolar wind,radioactive decay, meteor impacts, and breakdown of Mercury's crust.[4][5]Mercury's atmosphere is not stable and is constantly being refreshed because of its atoms escaping intospaceas a result of the planet's heat.

Venus

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Main article:Atmosphere of Venus
Atmosphere of Venus in UV, byPioneer Venus Orbiterin 1979

Venus' atmosphere is mostly composed ofcarbon dioxide.It contains minor amounts ofnitrogenand other trace elements, including compounds based onhydrogen,nitrogen,sulphur,carbon,andoxygen.The atmosphere of Venus is much hotter and denser than that of Earth, though shallower. As greenhouse gases warm a lower atmosphere, they cool the upper atmosphere, leading to compactthermospheres.[6][7]By some definitions, Venus has no stratosphere.[citation needed]

Thetropospherebegins at the surface and extends up to an altitude of 65 kilometres (an altitude at which themesospherehas already been reached on Earth). At the top of the troposphere, temperature and pressure reach Earth-like levels. Winds at the surface are a few metres per second, reaching 70 m/s or more in the upper troposphere. Thestratosphereand mesosphere extend from 65 km to 95 km in height. The thermosphere and exosphere begin at around 95 kilometres, eventually reaching the limit of the atmosphere at about 220 to 250 km.

The air pressure at Venus' surface is about 92 times that of the Earth. The enormous amount of CO2in the atmosphere creates a stronggreenhouse effect,raising the surface temperature to around 470 °C, hotter than that of any other planet in the Solar System.

Mars

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Main articles:Atmosphere of MarsandClimate of Mars

The Martian atmosphere is very thin and composed mainly ofcarbon dioxide,with somenitrogenandargon.The averagesurface pressureon Mars is 0.6-0.9kPa,compared to about 101 kPa for Earth. This results in a much lower atmosphericthermal inertia,and as a consequence Mars is subject to strongthermal tidesthat can change total atmospheric pressure by up to 10%. The thin atmosphere also increases the variability of the planet's temperature. Martian surface temperatures vary from lows of approximately −140 °C (−220 °F) during the polar winters to highs of up to 20 °C (70 °F) in summers.

The tenuous atmosphere of Mars visible on the horizon.
Pits in south polar ice cap, MGS 1999, NASA

Between theVikingandMars Global Surveyormissions, Mars saw "Much colder (10-20 K) global atmospheric temperatures were observed during the 1997 versus 1977 perihelion periods" and "that the global aphelion atmosphere of Mars is colder, less dusty, and cloudier than indicated by the established Viking climatology,"[8]with "generally colder atmospheric temperatures and lower dust loading in recent decades on Mars than during the Viking Mission."[9]TheMars Reconnaissance Orbiter,though spanning a much shorter dataset, shows no warming of planetary average temperature, and a possible cooling. "MCSMY 28 temperatures are an average of 0.9 (daytime) and 1.7 K (night- time) cooler thanTESMY 24 measurements. "[10]Locally and regionally, however, changes inpitsin the layer of frozencarbon dioxideat the Martian south pole observed between 1999 and 2001 suggest thesouth polar ice capis shrinking. More recent observations indicate that Mars' south pole is continuing to melt. "It's evaporating right now at a prodigious rate," saysMichael Malin,principal investigator for the Mars Orbiter Camera.[11]The pits in the ice are growing by about 3 meters (9.8 ft) per year. Malin states that conditions onMarsare not currently conductive to the formation of new ice. A web site has suggested that this indicates a "climate change in progress" onMars.[12]Multiple studies suggests this may be a local phenomenon rather than a global one.[13]

Colin Wilson has proposed that the observed variations are caused by irregularities in the orbit of Mars.[14]William Feldman speculates the warming could be because Mars might be coming out of anice age.[15]Other scientists state the warming may be a result ofalbedochanges from dust storms.[16][17]The study predicts the planet could continue to warm, as a result ofpositive feedback.[17]

On June 7, 2018, NASA announced that theCuriosityroverdetected a cyclical seasonal variation inatmospheric methane,as well as the presence ofkerogenand other complexorganic compounds.[18][19][20][21][22][23][24][25]

Giant Planets

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The four outer planets of the Solar System are allgiant planets:thegas giantsJupiter and Saturn, and theice giantsUranus and Neptune. They share some atmospheric commonalities. All have atmospheres that are mostlyhydrogenandheliumand that blend into the liquid interior at pressures greater than thecritical pressure,so that there is no clear boundary between atmosphere and body.

Jupiter

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Main article:Atmosphere of Jupiter
Oval BA on the left and the Great Red Spot on the right

Jupiter's upper atmosphere is composed of about 75% hydrogen and 24% helium by mass, with the remaining 1% consisting of other elements. The interior contains denser materials such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass. The atmosphere contains trace amounts ofmethane,water vapor,ammonia,andsilicon-based compounds. There are also traces ofcarbon,ethane,hydrogen sulfide,neon,oxygen,phosphine,andsulfur.The outermost layer of the atmosphere containscrystalsof frozen ammonia, possibly underlaid by a thin layer ofwater.

Jupiter is covered with a cloud layer about 50 km deep. The clouds are composed ofammoniacrystals and possibly ammonium hydrosulfide. The clouds are located in thetropopauseand are arranged into bands of differentlatitudes,known as tropical regions. These are sub-divided into lighter-huedzonesand darkerbelts.The interactions of these conflictingcirculationpatterns cause storms andturbulence.The best-known feature of the cloud layer is theGreat Red Spot,a persistentanticyclonicstormlocated 22° south of the equator that is larger than Earth. In 2000, an atmospheric feature formed in the southern hemisphere that is similar in appearance to the Great Red Spot, but smaller in size. The feature was namedOval BA,and has been nicknamed Red Spot Junior.

Observations of theRed Spot Jr.storm suggestJupitercould be in a period of global climate change.[26][27]This is hypothesized to be part of an approximately 70 year global climate cycle, characterized by the relatively rapid forming and subsequent slow erosion and merging of cyclonic and anticyclonicvorticesin Jupiter's atmosphere. These vortices facilitate the heat exchange between poles and equator. If they have sufficiently eroded, heat exchange is strongly reduced and regional temperatures may shift by as much as 10 K, with the poles cooling down and the equator region heating up. The resulting large temperature differential destabilizes the atmosphere and thereby leads to the creation of new vortices.[28][29]

Saturn

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The outer atmosphere ofSaturnconsists of about 93.2% hydrogen and 6.7% helium. Trace amounts of ammonia,acetylene,ethane, phosphine, and methane have also been detected. As with Jupiter, the upper clouds on Saturn are composed of ammonia crystals, while the lower level clouds appear to be composed of eitherammonium hydrosulfide(NH4SH) or water.

The Saturnian atmosphere is in several ways similar to that of Jupiter. It exhibits a banded pattern similar to Jupiter's, and occasionally exhibits long-lived ovals caused by storms. A storm formation analogous to Jupiter's Great Red Spot, the Great White Spot, is a short-lived phenomenon that forms with a roughly 30-year periodicity. It was last observed in 1990. However, the storms and the band pattern are less visible and active than those of Jupiter, due to the overlying ammonia hazes in Saturn's troposphere.

Saturn's atmosphere has several unusual features. Its winds are among the Solar System's fastest, withVoyagerdata indicating peak easterly winds of 500 m/s. It is also the only planet with a warm polar vortex, and is the only planet other than Earth whereeyewallclouds have been observed inhurricane-like structures.

Uranus

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Main articles:Atmosphere of UranusandClimate of Uranus

The atmosphere ofUranusis composed primarily of gas and various ices. It is about 83% hydrogen, 15% helium, 2% methane and traces of acetylene. Like Jupiter and Saturn, Uranus has a banded cloud layer, although this is not readily visible without enhancement of visual images of the planet. Unlike the larger giant planets, the low temperatures in the upper Uranian cloud layer, down to 50K,causes cloud formation from methane rather than ammonia.

Less storm activity has been observed in the Uranian atmosphere than in those of Jupiter or Saturn, due to the overlying methane and acetylene hazes in its atmosphere making the planet look like a bland, light blue globe.[citation needed]Images taken in 1997 with theHubble Space Telescopeshowed storm activity in that part of the atmosphere emerging from the 25-year-long Uranian winter. The general lack of storm activity may be related to the lack of an internal energy generation mechanism for Uranus, a feature unique among the giant planets.[30]

Neptune

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Great Dark Spot(top),Scooter(middle white cloud), andWizard's eye/Dark Spot 2 (bottom).

The atmosphere ofNeptuneis similar to that of Uranus. It is about 80% hydrogen, 19% helium, and 1.5% methane. However the weather activity on Neptune is much more active, and its atmosphere is much bluer than that of Uranus. The upper levels of the atmosphere reach temperatures of about 55K,giving rise to methane clouds in its troposphere, which gives the planet its ultramarine color. Temperatures rise steadily deeper inside the atmosphere.

Neptune has extremely dynamic weather systems, including the highest wind speeds in the Solar System, thought to be powered by the flow of internal heat. Typical winds in the banded equatorial region can possess speeds of around 350 m/s (comparable to the speed of sound at room temperature on Earth[31]viz. 343.6 m/s) while storm systems can have winds reaching up to around 900 m/s, in Neptune's atmosphere. Several large storm systems have been identified, including the Great Dark Spot, a cyclonic storm system the size of Eurasia, the Scooter, a white cloud group further south than the Great Dark Spot, and the Wizard's eye/Dark Spot 2, a southern cyclonic storm.

Neptune,the farthestplanetfrom Earth, has increased in brightness since 1980. Neptune's brightness is statistically correlated with its stratospheric temperature. Hammel and Lockwood hypothesize that the change in brightness includes a solar variation component as well as a seasonal component, though they did not find a statistically significant correlation withsolar variation.They propose that the resolution of this issue will be clarified by brightness observations in the next few years: forcing by a change in sub-solar latitude should be reflected in a flattening and decline of brightness, while solar forcing should be reflected in a flattening and then resumed rise of brightness.[32]

Other bodies in the Solar System

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Natural satellites

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Ten of the many natural satellites in the Solar System are known to have atmospheres:Europa,Io,Callisto,Enceladus,Ganymede,Titan,Rhea,Dione,TritonandEarth'sMoon.Ganymede and Europa both have very tenuous oxygen atmospheres, thought to be produced by radiation splitting the water ice present on the surface of these moons into hydrogen and oxygen. Io has an extremely thin atmosphere consisting mainly ofsulfur dioxide(SO
2), arising from volcanism and sunlight-driven sublimation of surface sulfur dioxide deposits. The atmosphere of Enceladus is also extremely thin and variable, consisting mainly of water vapor, nitrogen, methane, and carbon dioxide vented from the moon's interior throughcryovolcanism.The extremely thin carbon dioxide atmosphere of Callisto is thought to be replenished by sublimation from surface deposits.

Moon

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Main article:Atmosphere of the Moon

Titan

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Main article:Atmosphere of Titan
True-color image of layers of haze in Titan's atmosphere.

Titanhas by far the densest atmosphere of any moon. The Titanian atmosphere is in fact denser thanEarth's, with a surface pressure of 147kPa,one and a half times that of the Earth. The atmosphere is 94.2%nitrogen,5.65%methane,and 0.099%hydrogen,[33]with the remaining 1.6% composed of other gases such as hydrocarbons (includingethane,diacetylene,methylacetylene,cyanoacetylene,acetylene,propane),argon,carbon dioxide,carbon monoxide,cyanogen,hydrogen cyanideandhelium.The hydrocarbons are thought to form in Titan's upper atmosphere in reactions resulting from the breakup of methane by theSun'sultravioletlight, producing a thick orange smog. Titan has nomagnetic fieldand sometimes orbits outside Saturn'smagnetosphere,directly exposing it to thesolar wind.This mayionizeand carry away some molecules from the top of the atmosphere.

Titan's atmosphere supports an opaque cloud layer that obscures Titan's surface features at visible wavelengths. Thehazethat can be seen in the adjacent picture contributes to the moon'santi-greenhouse effectand lowers the temperature by reflecting sunlight away from the satellite. The thick atmosphere blocks most visible wavelength light from the Sun and other sources from reaching Titan's surface.

Triton

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Main article:Atmosphere of Triton

Triton,Neptune's largest moon, has a tenuous nitrogen atmosphere with small amounts of methane. Tritonian atmospheric pressure is about 1Pa.The surface temperature is at least 35.6 K, with the nitrogen atmosphere in equilibrium withnitrogen iceon Triton's surface.

Triton has increased in absolute temperature by 5% since 1989 to 1998.[34][35]A similar rise of temperature on Earth would be equal to about 11 °C (20 °F) increase in temperature in nine years. "At least since 1989, Triton has been undergoing a period of global warming. Percentage-wise, it's a very large increase," saidJames L. Elliot,who published the report.[34]

Triton is approaching an unusually warm summer season that only happens once every few hundred years. Elliot and his colleagues believe that Triton's warming trend could be driven by seasonal changes in the absorption of solar energy by its polar ice caps. One suggestion for this warming is that it is a result of frost patterns changing on its surface. Another is that ice albedo has changed, allowing for more heat from the Sun to be absorbed.[36]Bonnie J. Burattiet al.argue the changes in temperature are a result of deposition of dark, red material from geological processes on the moon, such as massive venting. Because Triton'sBond albedois among the highest within theSolar System,it is sensitive to small variations in spectralalbedo.[37]

Pluto

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Main article:Atmosphere of Pluto
Pluto-Norgay Montes(left-foreground);Hillary Montes(left-skyline);Sputnik Planitia(right)
Near-sunset view includes several layers ofatmospheric haze.

Plutohas an extremely thin atmosphere that consists ofnitrogen,methane,andcarbon monoxide,derived from the ices on its surface.[38]Two models[39][40]show that the atmosphere does not completely freeze and collapse when Pluto moves further from the Sun on its extremelyelliptical orbit.However, some other models do show this. Pluto needs 248 years for one complete orbit, and has been observed for less than one third of that time. It has an average distance of 39AUfrom the Sun, hence in-depth data from Pluto is sparse and difficult to gather. Temperature is inferred indirectly for Pluto; when it passes in front of a star, observers note how fast the light drops off. From this, they deduce the density of the atmosphere, and that is used as an indicator of temperature.

Pluto's atmosphere backlit by the Sun

One suchoccultationevent happened in 1988. Observations of a second occultation on August 20, 2002 suggest that Pluto's atmospheric pressure has tripled, indicating a warming of about 2 °C (3.6 °F),[41][42]as predicted by Hansen and Paige.[43]The warming is "likely not connected with that of the Earth," says Jay Pasachoff.[44] One astronomer has speculated the warming may be a result of eruptive activity, but it is more likely Pluto's temperature is heavily influenced by its elliptical orbit. It was closest to theSunin 1989 (perihelion) and has slowly receded since. If it has any thermal inertia, it is expected to warm for a while after it passes perihelion.[45]"This warming trend on Pluto could easily last for another 13 years," saysDavid J. Tholen.[41]It has also been suggested that a darkening of surface ice may also be the cause, but additional data and modeling is needed. Frost distribution on the surface of Pluto is significantly affected by the dwarf planet's high obliquity.[46]

Brown dwarfs

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Main article:Brown dwarf
Cloud models for the early T-type brown dwarfsSIMP J0136+09and2MASS J2139+02(left two panels) and the late T-type brown dwarf2M0050–3322.

Brown dwarfs have an atmosphere that produces a spectrum from late M-type, over L-type, T-type and finally arriving at Y-dwarf with decreasing temperature. The atmosphere ishydrogenrich and a brown dwarf is 70% hydrogen bymass.[47]Several chemical compounds are present in the atmosphere of brown dwarfs and their importance in shaping thespectrumchanges with temperature.Methaneandwater vaporfor example becomes more prominent for colder brown dwarfs.[48]

The physical properties can influence the atmosphere significantly. A lowsurface gravityof low-mass brown dwarfs or planetary-mass objects can bring the atmosphere in achemical disequilibrium.[49]Metallicitycan influence the amount of methane in the atmosphere and in the extreme case ofWISEA 1810−1010the methane feature is undetectable.

Several models for clouds in the atmosphere of brown dwarfs exist. Near the L/T transition these clouds consists ofironwith varying thickness, or of a patchysilicatecloud layer above a thick iron cloud layer.[50]Late T-dwarfs to early Y-dwarfs on the other hand have clouds made fromchromiumandpotassium chloride,as well as severalsulfides.At the lowest temperature of some Y-dwarfswater cloudsand possiblyammonium dihydrogen phosphateclouds might exist.[51]

Free-floating brown dwarfs rotate faster than Jupiter and studies have inferred the presence ofzonal winds.The brown dwarf2MASS J1047+21has a rotation period of 1.77 ± 0.04 hours and it has strong winds with speeds of 650±310m/sproceeding eastwards.[52]

Exoplanets

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Telescopic image of Comet17P/Holmesin 2007

Several planets outside the Solar System (exoplanets) have been observed to have atmospheres. At the present time, most atmosphere detections are of hot Jupiters or hot Neptunes that orbit very close to their star and thus have heated and extended atmospheres. Observations of exoplanet atmospheres are of two types. First, transmission photometry orspectradetect the light that passes through a planet's atmosphere as it transits in front of its star. Second, the direct emission from a planet atmosphere may be detected by differencing the star plus planet light obtained during most of the planet's orbit with the light of just the star during secondary eclipse (when the exoplanet is behind its star).[citation needed]

The first observation of an extrasolar planetary atmosphere was made in 2001.[53]Sodium in the atmosphere of the planetHD 209458 bwas detected during a set of four transits of the planet across its star. Later observations with theHubble Space Telescopeshowed an enormousellipsoidalenvelope ofhydrogen,carbonandoxygenaround the planet. This envelope reaches temperatures of 10,000 K. The planet is estimated to be losing(1–5)×108kgof hydrogen per second. This type of atmosphere loss may be common to all planets orbiting Sun-like stars closer than around 0.1 AU.[54]In addition to hydrogen, carbon, and oxygen, HD 209458 b is thought to havewater vaporin its atmosphere.[55][56][57]Sodium and water vapour has also been observed in the atmosphere ofHD 189733 b,[58][59]another hot gas giant planet.

In October 2013, the detection ofcloudsin theatmosphereofKepler-7bwas announced,[60][61]and, in December 2013, also in the atmospheres ofGliese 436 bandGliese 1214 b.[62][63][64][65]

In May 2017, glints of light fromEarth,seen as twinkling from an orbiting satellite a million kilometres away, were found to bereflected lightfromice crystalsin theatmosphere.[66][67]The technology used to determine this may be useful in studying the atmospheres of distant worlds, including those of exoplanets.

Atmospheric composition

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Planets of Red Dwarf Stars May Face Oxygen Loss

In 2001,sodiumwas detected in theatmosphereofHD 209458 b.[53]

In 2008,water,carbon monoxide,carbon dioxide[68]andmethane[69]were detected in theatmosphereofHD 189733 b.

In 2013,waterwas detected in the atmospheres of HD 209458 b,XO-1b,WASP-12b,WASP-17b,andWASP-19b.[70][71][72]

In July 2014, NASA announced finding very dryatmosphereson three exoplanets (HD 189733b,HD 209458b,WASP-12b) orbiting Sun-like stars.[73]

In September 2014, NASA reported thatHAT-P-11bis the first Neptune-sized exoplanet known to have a relatively cloud-free atmosphere and, as well, the first timemoleculesof any kind have been found, specificallywater vapor,on such a relatively small exoplanet.[74]

The presence of molecularoxygen(O
2) may be detectable by ground-based telescopes,[75]and it can be produced by geophysical processes, as well as a byproduct ofphotosynthesisby life forms, so although encouraging,O
2is not a reliablebiosignature.[76][77][78]In fact, planets with high concentration ofO
2in their atmosphere may be uninhabitable.[78]Abiogenesisin the presence of massive amounts of atmospheric oxygen could be difficult because early organisms relied on the free energy available inredox reactionsinvolving a variety of hydrogen compounds; on anO
2-rich planet, organisms would have to compete with the oxygen for this free energy.[78]

In June 2015, NASA reported thatWASP-33bhas astratosphere.Ozoneandhydrocarbonsabsorb large amounts of ultraviolet radiation, heating the upper parts of atmospheres that contain them, creating atemperature inversionand a stratosphere. However, these molecules are destroyed at the temperatures of hot exoplanets, creating doubt if the hot exoplanets could have a stratosphere. A temperature inversion, and stratosphere was identified on WASP-33b caused bytitanium oxide,which is a strong absorber of visible and ultraviolet radiation, and can only exist as a gas in a hot atmosphere. WASP-33b is the hottest exoplanet known, with a temperature of 3,200 °C (5,790 °F)[79]and is approximately four and a half times the mass of Jupiter.[80][81]

In February 2016, it was announced thatNASA'sHubble Space Telescopehad detectedhydrogenandhelium(and suggestions ofhydrogen cyanide), but nowater vapor,in theatmosphereof55 Cancri e,the first time the atmosphere of asuper-Earthexoplanet was analyzed successfully.[82]

In September 2019, two independent research studies concluded, fromHubble Space Telescopedata, that there were significant amounts of water in the atmosphere of exoplanetK2-18b,the first such discovery for a planet within a star's habitable zone.[83][84][85]

On 24 Aug 2022, NASA published the discovery by theJames Webb Space Telescopeof carbon dioxide in the atmosphere ofWASP-39b.[86][87]

Missing Methane Problem

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Carbon monoxide should be replaced by methane as the dominant carbon-bearing molecule in the atmosphere of exoplanets at temperatures below 1000K.While methane is detected in solar system objects, young directly imaged exoplanets and in free-floating brown dwarfs (T/Y-dwarfs), it is rarely detected in transiting exoplanets. This observation was dubbed theMissing Methane Problem.Some studies tried to explain this with a depletion of methane. The most solid detection of methane is in the atmosphere of the warm Jupiter (825 K)WASP-80b,which was detected withNIRCam.This detection is in agreement with models that do not require a strong methane depletion. This detection suggested that other instruments did not have the wavelength coverage or precision needed to detect methane.[88]Non-detection of methane inHD 209458bon the other hand showed that the missing methane problem cannot be resolved for all exoplanets with JWST and an explanation for the missing methane is required. Explanations often involve a highmetallicityand a lowcarbon-to-oxygenratio.[88][89]

A similar problem exists for the detection of ammonia.[90]Methane and ammonia is detected in free-floating Y-dwarfs (Teff<400 K), such asWISE 0359−5401.Transiting exoplanets on the other hand do rarely show ammonia. For example the ~300 K exoplanetsK2-18bshowed a depletion of methane and ammonia[91]and more recent observations withNIRISSandNIRSpecwas able to resolve the methane problem for K2-18b. The observations showed strong absorption due to methane, but was not able to detect any ammonia in K2-18b.[92]The research team explained this missing ammonia with an ocean that absorbs certain gases. Other researchers are more cautious about this ocean claim.[93]One problem is that ammonia and methane absorption overlap in the near-infrared. Ammonia absorption could be mistaken as methane and mid-infrared detections of ammonia are much clearer, such as in WISE 0359−5401 withMIRI.

Another problem exists forphosphine(PH3) which is a strong absorber in Jupiter, but does not appear in similar cold free-floating T- and Y-dwarfs, such asWISE 0855−0714,WISE 0359−5401,WISE 1828+2650and2MASS 0415−0935.One explanation is that the behaviour ofphosphorusin the atmosphere of brown dwarfs to giant exoplanets is not well understood.[94]

Atmospheric circulation

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See also:Exometeorology

Theatmospheric circulationof planets that rotate more slowly or have a thicker atmosphere allows more heat to flow to the poles which reduces the temperature differences between the poles and the equator.[95]

Winds

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Winds of over 2 km/s—which is seven times thespeed of soundor 20 times faster than the fastest ever winds known on Earth—have been discovered flowing around the planetHD 189733b.[96][97]

Clouds

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An artist's impression of a gas giant with patchy silicate clouds on top of an iron cloud deck.
HD 189733b,which is a hot Jupiter. This artist's impression shows its predicted blue color and its night- and dayside clouds.

The composition of clouds ingas giantsdepend on temperature. A cloud layer does "sink" with decreasing temperature. This way one exoplanet might have a cloud layer at a higher pressure (lower altitude) compared to a warmer exoplanet.[50][51]High altitude clouds often block light coming from deeper layers of the atmosphere, includingchemical absorption features.Weaker than normal absorption features is the main method to detect the presence of clouds viatransmission spectroscopy.[98]In some cases the absorption from the clouds can be directly observed, such as quartz-clouds onWASP-17bwithJWST.[99]One way to predict the appearance of a gas giant is theSudarsky's gas giant classification.But this classification scheme is over two decades old and more recent models[51]sometimes predict thin clouds for class III and class IV. This classification also does not consider ultra-hot Jupiters, which do have nightside clouds.[100]Relative cloud-free atmospheres also exist.[101]

Similar to brown dwarfs the composition at hotter temperature (class V or >900 K)[51]is a thick iron cloud deck withsilicateclouds (quartz,corundum,fosteriteand/orenstatite) on top. This top layer can be patchy and cover 70-90% of the planet.[50][102]At lower temperatures (class III-IV or 400-1,300 K) the iron and silicate clouds sink deep into the atmosphere and thin clouds made ofchromium,potassium chlorideand especiallysulfides(manganese sulfide,sodium sulfideandzink sulfide) become more important. At low temperatures (class II <400 K)water cloudsand possiblyammonium dihydrogen phosphateclouds might exist. But lower layers of clouds of sulfides and potassium chloride should exist at this temperature.[51]Jupiter and Saturn-like atmospheres (class I or <150 K) are dominated byammoniaclouds, but lower layers of water clouds might exist.[103]

A newer type of exoplanets, calledultra-hot Jupitershave a temperature above 2,000 K and have a cloud-free dayside[100]with molecules often dissociated into atoms or ions. A wide variety of atomic lines were detected in the transmission spectra of the ultra-hot Jupiters.[104][105][106]The nightside can be up to 2,500 K colder than the dayside and inWASP-18bthis temperature drop causes clouds to form at theterminator.At the equator of the terminator, which forms clouds on WASP-18b (in the west seen from the dayside) the cloud top is made of thin layers dominated bytitanium dioxide,corundum (aluminium oxide),perovskite(calcium titanate) andiron.The majority of the vertical portion of the cloud is made up of clouds of enstatite, fosterite,periclase(magnesium oxide), quartz, iron and inclusion of other material. The cloud bottom changes from quartz dominated, to iron, then corundum and then perovskite dominated. These bottom layers have large particle sizes of about 60 μm. At other positions of the terminator these clouds change their composition and particle size.[100]The cloud-free dayside and the cloudy terminator/nightside would make these ultra-hot Jupiters look similar to aneyeball planet.

In October 2013, the detection ofcloudsin the atmosphere ofKepler-7bwas announced,[60][61]and, in December 2013, also in the atmospheres ofGJ 436 bandGJ 1214 b.[62][63][64][65]

Precipitation

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Precipitationin the form of liquid (rain) or solid (snow) varies in composition depending on atmospheric temperature, pressure, composition, andaltitude.Hot atmospheres could have iron rain,[107]molten-glass rain,[108]and rain made from rocky minerals such as enstatite,corundum,spinel,andwollastonite.[109]Deep in the atmospheres of gas giants, it could rain diamonds[110]and helium containing dissolved neon.[111]

Abiotic oxygen

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There are geological and atmospheric processes that produce free oxygen, so the detection of oxygen is not necessarily an indication of life.[112]

The processes of life result in a mixture of chemicals that are not inchemical equilibriumbut there are also abiotic disequilibrium processes that need to be considered. The most robust atmosphericbiosignatureis often considered to be molecularoxygen(O
2) and itsphotochemicalbyproductozone(O
3). Thephotolysisof water (H
2O) byUV raysfollowed byhydrodynamic escapeof hydrogen can lead to a build-up of oxygen in planets close to their star undergoingrunaway greenhouse effect.For planets in thehabitable zone,it was thought that water photolysis would be strongly limited bycold-trappingof water vapour in the lower atmosphere. However, the extent of H2O cold-trapping depends strongly on the amount of non-condensiblegases in the atmosphere such asnitrogenN2andargon.In the absence of such gases, the likelihood of build-up of oxygen also depends in complex ways on the planet's accretion history, internal chemistry, atmospheric dynamics, and orbital state. Therefore, oxygen, on its own, cannot be considered a robust biosignature.[113]The ratio of nitrogen and argon to oxygen could be detected by studyingthermalphase curves[114]or bytransittransmission spectroscopy measurement of the spectralRayleigh scatteringslope in a clear-sky (i.e.aerosol-free) atmosphere.[115]

Life

[edit]
Main articles:Planetary habitabilityandBiosignature

Methane

[edit]

Detection of methane in astronomical bodies is of interest to science and technology, as it may be evidence of extraterrestrial life (biosignature),[116][117]it may help provide organic ingredientsfor life to form,[116][118][119]and also, methane could be used as a fuel or rocket propellant for future robotic and crewed missions in the Solar System.[120][121]

  • Mercury– the tenuous atmosphere contains trace amounts of methane.[122]
  • Venus– the atmosphere may contain a large amount of methane from 60 km (37 mi) to the surface according to data collected by thePioneer VenusLarge Probe NeutralMass Spectrometer[123]
  • Moon– traces are outgassed from the surface[124]
Methane(CH4) on Mars – potential sources and sinks.
  • Mars– theMartian atmospherecontains 10 nmol/molmethane.[125]The source of methane on Mars has not been determined. Research suggests that methane may come fromvolcanoes,fault lines,ormethanogens,[126]that it may be a byproduct of electrical discharges fromdust devilsanddust storms,[127]or that it may be the result ofUVradiation.[128]In January 2009, NASA scientists announced that they had discovered that the planet often vents methane into the atmosphere in specific areas, leading some to speculate this may be a sign of biological activity below the surface.[129]TheCuriosityrover,which landed on Mars in August 2012, can distinguish between differentisotopologuesof methane;[130]but even if the mission determines that microscopic Martian life is the source of the methane, it probably resides far below the surface, beyond the rover's reach.[131]The first measurements with theTunable Laser Spectrometer (TLS)indicated that there is less than 5 ppb of methane at the landing site.[132][133]On 16 December 2014, NASA reported theCuriosityrover detected a "tenfold spike", likely localized, in the amount of methane in the Martian atmosphere. Sample measurements taken "a dozen times over 20 months" showed increases in late 2013 and early 2014, averaging "7 parts of methane per billion in the atmosphere." Before and after that, readings averaged around one-tenth that level.[134][135]The spikes in concentration suggest that Mars is episodically producing or releasing methane from an unknown source.[136]TheExoMars Trace Gas Orbiterwill perform measurements of methane starting in April 2018, as well as its decomposition products such asformaldehydeandmethanol.
  • Jupiter– the atmosphere contains 3000 ± 1000 ppm methane[137]
  • Saturn– the atmosphere contains 4500 ± 2000 ppm methane[138]
    • Enceladus– the atmosphere contains 1.7% methane[139]
    • Iapetus[citation needed]
    • Titan– the atmosphere contains 1.6% methane and thousands of methane lakes have been detected on the surface.[140]In the upper atmosphere, methane is converted into more complex molecules includingacetylene,a process that also produces molecularhydrogen.There is evidence that acetylene and hydrogen are recycled into methane near the surface. This suggests the presence of either an exotic catalyst or an unknown form of methanogenic life.[141]Methane showers, probably prompted by changing seasons, have also been observed.[142]On October 24, 2014, methane was found in polar clouds on Titan.[143][144]
Polar clouds, made of methane, on Titan (left) compared withpolar cloudsonEarth(right).
  • Uranus– the atmosphere contains 2.3% methane[145]
    • Ariel– methane is believed to be a constituent of Ariel's surface ice
    • Miranda[citation needed]
    • Oberon– about 20% of Oberon's surface ice is composed of methane-related carbon/nitrogen compounds
    • Titania– about 20% of Titania's surface ice is composed of methane-related organic compounds[citation needed]
    • Umbriel– methane is a constituent of Umbriel's surface ice
  • Neptune– the atmosphere contains 1.5 ± 0.5% methane[146]
    • Triton– Triton has a tenuous nitrogen atmosphere with small amounts of methane near the surface.[147][148]
  • Pluto–spectroscopicanalysis of Pluto's surface reveals it to contain traces of methane[149][150]
    • Charon– methane is believed present on Charon, but it is not completely confirmed[151]
  • Eris– infrared light from the object revealed the presence of methane ice[152]
  • Halley's Comet
  • Comet Hyakutake– terrestrial observations foundethaneand methane in the comet[153]
  • Extrasolar planets– methane was detected on extrasolar planetHD 189733b;this is the first detection of an organic compound on a planet outside the solar system. Its origin is unknown, since the planet's high temperature (700 °C) would normally favor the formation ofcarbon monoxideinstead.[154]Research indicates thatmeteoroidsslamming againstexoplanetatmospheres could add hydrocarbon gases such as methane, making the exoplanets look as though they are inhabited by life, even if they are not.[155]
  • Interstellar clouds[156]
  • The atmospheres ofM-type stars.[157]

See also

[edit]

References

[edit]
  1. ^"Department of Atmospheric Science, University of Washington".Retrieved2007-05-24.
  2. ^"NASA GISS: Research in Planetary Atmospheres".Archived fromthe originalon 2007-05-16.Retrieved2007-05-24.
  3. ^Gertner, Jon (15 September 2022)."The Search for Intelligent Life Is About to Get a Lot More Interesting - There are an estimated 100 billion galaxies in the universe, home to an unimaginable abundance of planets. And now there are new ways to spot signs of life on them".The New York Times.Retrieved15 September2022.
  4. ^"Thin Atmosphere of Mercury, Formation and Composition - Windows to the Universe".www.windows.ucar.edu.Archived fromthe originalon 2010-03-27.Retrieved2007-05-25.
  5. ^"ESA Science & Technology: Mercury Atmosphere".esa.int.21 July 2012. Archived fromthe originalon 21 July 2012.
  6. ^Picone, J.;Lean, J.(2005). "Global Change in the Thermosphere: Compelling Evidence of a Secular Decrease in Density".2005 NRL Review:225–227.
  7. ^Lewis, H.; et al. (April 2005). "Response of the Space Debris Environment to Greenhouse Cooling".Proceedings of the 4th European Conference on Space Debris.587:243.Bibcode:2005ESASP.587..243L.
  8. ^Clancy, R. (April 25, 2000)."An intercomparison of ground-based millimeter, MGS TES, and Viking atmospheric temperature measurements: Seasonal and interannual variability of temperatures and dust loading in the global Mars atmosphere".Journal of Geophysical Research.105(4): 9553–9571.Bibcode:2000JGR...105.9553C.doi:10.1029/1999JE001089.
  9. ^Bell, J; et al. (August 28, 2009)."Mars Reconnaissance Orbiter Mars Color Imager (MARCI): Instrument Description, Calibration, and Performance".Journal of Geophysical Research.114(8): E08S92.Bibcode:2009JGRE..114.8S92B.doi:10.1029/2008je003315.S2CID140643009.
  10. ^Bandfield, J. L.; et al. (2013). "Radiometric Comparison of Mars Climate Sounder and Thermal Emission Spectrometer Measurements".Icarus.225(1): 28–39.Bibcode:2013Icar..225...28B.doi:10.1016/j.icarus.2013.03.007.
  11. ^Reddy, Francis (2005-09-23)."MGS sees changing face of Mars".Astronomy.Retrieved2007-02-22.
  12. ^"Orbiter's Long Life Helps Scientists Track Changes on Mars".NASA.2005-09-20. Archived fromthe originalon April 30, 2007.Retrieved2007-05-09.
  13. ^Liu, J.; Richardson, M. (August 2003)."An assessment of the global, seasonal, and interannual spacecraft record of Martian climate in the thermal infrared".Journal of Geophysical Research.108(8): 5089.Bibcode:2003JGRE..108.5089L.doi:10.1029/2002je001921.S2CID7433260.
  14. ^Ravilious, Kate (2007-03-28)."Mars Melt Hints at Solar, Not Human, Cause for Warming, Scientist Says".National Geographic Society.Archived fromthe originalon March 2, 2007.Retrieved2007-05-09.
  15. ^"Mars Emerging from Ice Age, Data Suggest".Space.com.2003-12-08.Retrieved2007-05-10.
  16. ^Fenton, Lori K.; et al. (2007-04-05)."Global warming and climate forcing by recent of albedo changes on Mars"(PDF).Nature.446(7136): 646–649.Bibcode:2007Natur.446..646F.doi:10.1038/nature05718.PMID17410170.S2CID4411643.Archived fromthe original(PDF)on 2007-07-08.Retrieved2007-05-09.
  17. ^abRavilious, Kate (2007-04-04)."Mars Warming Due to Dust Storms, Study Finds".National Geographic Society.Archived fromthe originalon April 9, 2007.Retrieved2007-05-19.
  18. ^Brown, Dwayne; Wendel, JoAnna; Steigerwald, Bill; Jones, Nancy; Good, Andrew (June 7, 2018)."Release 18-050 - NASA Finds Ancient Organic Material, Mysterious Methane on Mars".NASA.RetrievedJune 7,2018.
  19. ^NASA (June 7, 2018)."Ancient Organics Discovered on Mars - video (03:17)".NASA.Archivedfrom the original on 2021-12-21.RetrievedJune 7,2018.
  20. ^Wall, Mike (June 7, 2018)."Curiosity Rover Finds Ancient 'Building Blocks for Life' on Mars".Space.com.RetrievedJune 7,2018.
  21. ^Chang, Kenneth (June 7, 2018)."Life on Mars? Rover's Latest Discovery Puts It 'On the Table' - The identification of organic molecules in rocks on the red planet does not necessarily point to life there, past or present, but does indicate that some of the building blocks were present".The New York Times.RetrievedJune 8,2018.
  22. ^Voosen, Paul (June 7, 2018)."NASA rover hits organic pay dirt on Mars".Science.doi:10.1126/science.aau3992.S2CID115442477.RetrievedJune 7,2018.
  23. ^ten Kate, Inge Loes (June 8, 2018)."Organic molecules on Mars".Science.360(6393): 1068–1069.Bibcode:2018Sci...360.1068T.doi:10.1126/science.aat2662.PMID29880670.S2CID195666358.
  24. ^Webster, Christopher R.; et al. (June 8, 2018)."Background levels of methane in Mars' atmosphere show strong seasonal variations".Science.360(6393): 1093–1096.Bibcode:2018Sci...360.1093W.doi:10.1126/science.aaq0131.PMID29880682.
  25. ^Eigenbrode, Jennifer L.; et al. (June 8, 2018)."Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars".Science.360(6393): 1096–1101.Bibcode:2018Sci...360.1096E.doi:10.1126/science.aas9185.hdl:10044/1/60810.PMID29880683.
  26. ^Marcus, Philip S.; et al. (November 2006). "Velocities and Temperatures of Jupiter's Great Red Spot and the New Red Oval and Implications for Global Climate Change".APS Division of Fluid Dynamics Meeting Abstracts.59:FG.005.Bibcode:2006APS..DFD.FG005M.
  27. ^Goudarzi, Sara (2006-05-04)."New Storm on Jupiter Hints at Climate Change".Space.com.Retrieved2007-05-09.
  28. ^Marcus, Philip S. (2004-04-22)."Prediction of a global climate change on Jupiter"(PDF).Nature.428(6985): 828–831.Bibcode:2004Natur.428..828M.doi:10.1038/nature02470.PMID15103369.S2CID4412876.Archived fromthe original(PDF)on 2007-04-16.Retrieved2007-05-09.
  29. ^Yang, Sarah (2004-04-21)."Researcher predicts global climate change on Jupiter as giant planet's spots disappear".University of California, Berkeley.Retrieved2007-05-09.
  30. ^"Uranus' Atmosphere".Retrieved2007-05-23.
  31. ^"Speed of sound calculation".
  32. ^"AGU - American Geophysical Union".AGU.Archived fromthe originalon 2012-11-02.Retrieved2007-05-10.
  33. ^Catling, David C.; Kasting, James F. (10 May 2017). Atmospheric Evolution on Inhabited and Lifeless Worlds (1 ed.). Cambridge University Press.ISBN978-0521844123.
  34. ^ab"MIT researcher finds evidence of global warming on Neptune's largest moon".Massachusetts Institute of Technology.1998-06-24.Retrieved2007-05-10.
  35. ^Elliot, James L.;et al. (1998-06-25)."Global warming on Triton".Nature.393(6687): 765–767.Bibcode:1998Natur.393..765E.doi:10.1038/31651.S2CID40865426.Archived fromthe originalon 2011-05-20.Retrieved2007-05-10.
  36. ^"Global Warming Detected on Triton".Scienceagogo.com. 1998-05-28.Retrieved2007-05-10.
  37. ^Buratti, Bonnie J.; et al. (1999-01-21)."Does global warming make Triton blush?".Nature.397(6716): 219–20.Bibcode:1999Natur.397..219B.doi:10.1038/16615.PMID9930696.
  38. ^Ken Croswell (1992)."Nitrogen in Pluto's Atmosphere".Retrieved2007-04-27.
  39. ^Hansen, C; Paige, D (Apr 1996). "Seasonal Nitrogen Cycles on Pluto".Icarus.120(2): 247–265.Bibcode:1996Icar..120..247H.CiteSeerX10.1.1.26.4515.doi:10.1006/icar.1996.0049.
  40. ^Olkin, C; Young, L; et al. (March 2014)."Evidence That Pluto's Atmosphere Does Not Collapse From Occultations Including The 2013 May 04 Event".Icarus.246:220–225.Bibcode:2015Icar..246..220O.doi:10.1016/j.icarus.2014.03.026.hdl:10261/167246.
  41. ^abBritt, Roy (2002-10-09)."Global Warming on Pluto Puzzles Scientists".Space.com.Retrieved2007-05-09.
  42. ^Elliot, James L.;et al. (2003-07-10)."The recent expansion of Pluto's atmosphere"(PDF).Nature.424(6945): 165–168.Bibcode:2003Natur.424..165E.doi:10.1038/nature01762.PMID12853949.S2CID10512970.Archived fromthe original(PDF)on 2007-04-17.Retrieved2007-05-10.
  43. ^Staff (April 2014)."Postcards from Pluto".Tumblr.RetrievedMarch 1,2015.
  44. ^"Pluto is undergoing global warming, researchers find".Massachusetts Institute of Technology.2002-10-09.Retrieved2007-05-09.
  45. ^Lakdawalla, E. (April 17, 2013)."Pluto's atmosphere does not collapse".RetrievedNovember 11,2014.
  46. ^Hansen, Candice J.; Paige, David A. (April 1996). "Seasonal Nitrogen Cycles on Pluto".Icarus.120(2): 247–265.Bibcode:1996Icar..120..247H.CiteSeerX10.1.1.26.4515.doi:10.1006/icar.1996.0049.
  47. ^"Brown Dwarf - an overview | ScienceDirect Topics".www.sciencedirect.com.Retrieved2023-10-16.The brown dwarfs are distinguished from white dwarfs first by their very cool surface temperatures and second by the fact that their internal composition is practically unchanged from the time of formation; that is, it is about 71% hydrogen by mass.
  48. ^Marley, Mark S.; Saumon, Didier; Visscher, Channon; Lupu, Roxana; Freedman, Richard; Morley, Caroline; Fortney, Jonathan J.; Seay, Christopher; Smith, Adam J. R. W.; Teal, D. J.; Wang, Ruoyan (2021-10-01)."The Sonora Brown Dwarf Atmosphere and Evolution Models. I. Model Description and Application to Cloudless Atmospheres in Rainout Chemical Equilibrium".The Astrophysical Journal.920(2): 85.arXiv:2107.07434.Bibcode:2021ApJ...920...85M.doi:10.3847/1538-4357/ac141d.ISSN0004-637X.See Figure 3 to 7
  49. ^Zahnle, Kevin J.; Marley, Mark S. (2014-12-01)."Methane, Carbon Monoxide, and Ammonia in Brown Dwarfs and Self-Luminous Giant Planets".The Astrophysical Journal.797(1): 41.arXiv:1408.6283.Bibcode:2014ApJ...797...41Z.doi:10.1088/0004-637X/797/1/41.ISSN0004-637X.
  50. ^abcVos, Johanna M.; Burningham, Ben; Faherty, Jacqueline K.; Alejandro, Sherelyn; Gonzales, Eileen; Calamari, Emily; Bardalez Gagliuffi, Daniella; Visscher, Channon; Tan, Xianyu; Morley, Caroline V.; Marley, Mark; Gemma, Marina E.; Whiteford, Niall; Gaarn, Josefine; Park, Grace (2023-02-01)."Patchy Forsterite Clouds in the Atmospheres of Two Highly Variable Exoplanet Analogs".The Astrophysical Journal.944(2): 138.arXiv:2212.07399.Bibcode:2023ApJ...944..138V.doi:10.3847/1538-4357/acab58.ISSN0004-637X.
  51. ^abcdeMorley, Caroline V.; Fortney, Jonathan J.; Marley, Mark S.; Visscher, Channon; Saumon, Didier; Leggett, S. K. (2012-09-01)."Neglected Clouds in T and Y Dwarf Atmospheres".The Astrophysical Journal.756(2): 172.arXiv:1206.4313.Bibcode:2012ApJ...756..172M.doi:10.1088/0004-637X/756/2/172.ISSN0004-637X.S2CID118398946.
  52. ^Allers, Katelyn. N.; Vos, Johanna M.; Biller, Beth A.; Williams, Peter. K. G. (2020-04-01)."A measurement of the wind speed on a brown dwarf".Science.368(6487): 169–172.Bibcode:2020Sci...368..169A.doi:10.1126/science.aaz2856.hdl:20.500.11820/06e2e379-467a-456f-956c-b37912b8d95a.ISSN0036-8075.PMID32273464.S2CID264645727.
  53. ^abCharbonneau, David; et al. (2002). "Detection of an Extrasolar Planet Atmosphere".The Astrophysical Journal.568(1): 377–384.arXiv:astro-ph/0111544.Bibcode:2002ApJ...568..377C.doi:10.1086/338770.S2CID14487268.
  54. ^Hébrard, G.; Lecavelier des Étangs, A.; Vidal-Madjar, A.; Désert, J. -M.; Ferlet, R. (2003). "Evaporation rate of hot Jupiters and formation of Chthonian planets".arXiv:astro-ph/0312384.
  55. ^Water Found in Extrasolar Planet's Atmosphere- Space.com
  56. ^Signs of water seen on planet outside solar system,by Will Dunham, Reuters, Tue April 10, 2007 8:44PM EDT
  57. ^Water Identified in Extrasolar Planet AtmosphereArchived2007-05-16 at theWayback Machine,Lowell Observatorypress release, April 10, 2007
  58. ^Khalafinejad, S.; Essen, C. von; Hoeijmakers, H. J.; Zhou, G.; Klocová, T.; Schmitt, J. H. M. M.; Dreizler, S.; Lopez-Morales, M.; Husser, T.-O. (2017-02-01). "Exoplanetary atmospheric sodium revealed by orbital motion".Astronomy & Astrophysics.598:A131.arXiv:1610.01610.Bibcode:2017A&A...598A.131K.doi:10.1051/0004-6361/201629473.ISSN0004-6361.S2CID55263138.
  59. ^"Press Release: NASA's Spitzer Finds Water Vapor on Hot, Alien Planet".caltech.edu.Archived fromthe originalon 2007-07-15.Retrieved2007-07-22.
  60. ^abChu, Jennifer (October 2, 2013)."Scientists generate first map of clouds on an exoplanet".MIT.RetrievedJanuary 2,2014.
  61. ^abDemory, Brice-Olivier; et al. (September 30, 2013). "Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere".The Astrophysical Journal.776(2): L25.arXiv:1309.7894.Bibcode:2013ApJ...776L..25D.doi:10.1088/2041-8205/776/2/L25.S2CID701011.
  62. ^abHarrington, J.D.; Weaver, Donna; Villard, Ray (December 31, 2013)."Release 13-383 - NASA's Hubble Sees Cloudy Super-Worlds With Chance for More Clouds".NASA.RetrievedJanuary 1,2014.
  63. ^abMoses, Julianne (January 1, 2014). "Extrasolar planets: Cloudy with a chance of dustballs".Nature.505(7481): 31–32.Bibcode:2014Natur.505...31M.doi:10.1038/505031a.PMID24380949.S2CID4408861.
  64. ^abKnutson, Heather; et al. (January 1, 2014). "A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b".Nature.505(7481): 66–68.arXiv:1401.3350.Bibcode:2014Natur.505...66K.doi:10.1038/nature12887.PMID24380953.S2CID4454617.
  65. ^abKreidberg, Laura; et al. (January 1, 2014). "Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b".Nature.505(7481): 69–72.arXiv:1401.0022.Bibcode:2014Natur.505...69K.doi:10.1038/nature12888.PMID24380954.S2CID4447642.
  66. ^St. Fleur, Nicholas (19 May 2017)."Spotting Mysterious Twinkles on Earth From a Million Miles Away".The New York Times.Retrieved20 May2017.
  67. ^Marshak, Alexander; Várnai, Tamás; Kostinski, Alexander (15 May 2017)."Terrestrial glint seen from deep space: oriented ice crystals detected from the Lagrangian point".Geophysical Research Letters.44(10): 5197.Bibcode:2017GeoRL..44.5197M.doi:10.1002/2017GL073248.hdl:11603/13118.S2CID109930589.
  68. ^Swain, M. R.; Vasisht, G.; Tinetti, G.; Bouwman, J.; Chen, P.; Yung, Y.; Deming, D.; Deroo, P. (2009). "Molecular Signatures in the Near Infrared Dayside Spectrum of HD 189733b".The Astrophysical Journal.690(2): L114.arXiv:0812.1844.Bibcode:2009ApJ...690L.114S.doi:10.1088/0004-637X/690/2/L114.S2CID10720307.
  69. ^NASA – Hubble Finds First Organic Molecule on an Exoplanet.NASA. 19 March 2008
  70. ^"Hubble Traces Subtle Signals of Water on Hazy Worlds".NASA.3 December 2013.Retrieved4 December2013.
  71. ^Deming, D.; Wilkins, A.; McCullough, P.; Burrows, A.; Fortney, J. J.; Agol, E.; Dobbs-Dixon, I.; Madhusudhan, N.; Crouzet, N.; Desert, J. M.; Gilliland, R. L.; Haynes, K.; Knutson, H. A.; Line, M.; Magic, Z.; Mandell, A. M.; Ranjan, S.; Charbonneau, D.; Clampin, M.; Seager, S.; Showman, A. P. (2013). "Infrared Transmission Spectroscopy of the Exoplanets HD 209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope".The Astrophysical Journal.774(2): 95.arXiv:1302.1141.Bibcode:2013ApJ...774...95D.doi:10.1088/0004-637X/774/2/95.S2CID10960488.
  72. ^Mandell, A. M.; Haynes, K.; Sinukoff, E.; Madhusudhan, N.; Burrows, A.; Deming, D. (2013). "Exoplanet Transit Spectroscopy Using WFC3: WASP-12 b, WASP-17 b, and WASP-19 b".The Astrophysical Journal.779(2): 128.arXiv:1310.2949.Bibcode:2013ApJ...779..128M.doi:10.1088/0004-637X/779/2/128.S2CID52997396.
  73. ^Harrington, J.D.; Villard, Ray (24 July 2014)."RELEASE 14–197 – Hubble Finds Three Surprisingly Dry Exoplanets".NASA.Retrieved25 July2014.
  74. ^Clavin, Whitney; Chou, Felicia; Weaver, Donna; Villard; Johnson, Michele (24 September 2014)."NASA Telescopes Find Clear Skies and Water Vapor on Exoplanet".NASA.Retrieved24 September2014.
  75. ^Kawahara, H.; Matsuo, T.; Takami, M.; Fujii, Y.; Kotani, T.; Murakami, N.; Tamura, M.; Guyon, O. (2012). "Can Ground-based Telescopes Detect the Oxygen 1.27 μm Absorption Feature as a Biomarker in Exoplanets?".The Astrophysical Journal.758(1): 13.arXiv:1206.0558.Bibcode:2012ApJ...758...13K.doi:10.1088/0004-637X/758/1/13.S2CID119261987.
  76. ^Narita, Norio (2015)."Titania may produce abiotic oxygen atmospheres on habitable exoplanets".Scientific Reports.5:13977.arXiv:1509.03123.Bibcode:2015NatSR...513977N.doi:10.1038/srep13977.PMC4564821.PMID26354078.
  77. ^Léger, Alain (2004). "A New Family of Planets?" Ocean Planets "".Icarus.169(2): 499–504.arXiv:astro-ph/0308324.Bibcode:2004Icar..169..499L.doi:10.1016/j.icarus.2004.01.001.S2CID119101078.
  78. ^abcLuger, R; Barnes, R (2015)."Extreme water loss and abiotic O2 buildup on planets throughout the habitable zones of M dwarfs".Astrobiology.15(2): 119–43.arXiv:1411.7412.Bibcode:2015AsBio..15..119L.doi:10.1089/ast.2014.1231.PMC4323125.PMID25629240.
  79. ^"Hottest planet is hotter than some stars".Retrieved2015-06-12.
  80. ^"NASA's Hubble Telescope Detects 'Sunscreen' Layer on Distant Planet".2015-06-11.Retrieved2015-06-11.
  81. ^Haynes, Korey; Mandell, Avi M.; Madhusudhan, Nikku; Deming, Drake; Knutson, Heather (2015-05-06). "Spectroscopic Evidence for a Temperature Inversion in the Dayside Atmosphere of the Hot Jupiter WASP-33b".The Astrophysical Journal.806(2): 146.arXiv:1505.01490.Bibcode:2015ApJ...806..146H.doi:10.1088/0004-637X/806/2/146.S2CID35485407.
  82. ^Staff (16 February 2016)."First detection of super-earth atmosphere".Phys.org.Retrieved17 February2016.
  83. ^Ghosh, Pallab (11 September 2019)."Water found on 'habitable' planet".BBC News.Retrieved12 September2019.
  84. ^Greshko, Michael (11 September 2019)."Water found on a potentially life-friendly alien planet".National Geographic.Archived fromthe originalon September 11, 2019.Retrieved12 September2019.
  85. ^Tsiaras, Angelo; et al. (11 September 2019). "Water vapour in the atmosphere of the habitable-zone eight-Earth-mass planet K2-18 b".Nature Astronomy.3(12): 1086–1091.arXiv:1909.05218.Bibcode:2019NatAs...3.1086T.doi:10.1038/s41550-019-0878-9.S2CID202558393.
  86. ^"The James Webb telescope spotted CO2 in an exoplanet's atmosphere".Science News.2022-08-26.Retrieved2022-08-28.
  87. ^The JWST Transiting Exoplanet Community Early Release Science Team; Ahrer, Eva-Maria; Alderson, Lili; Batalha, Natalie M.; Batalha, Natasha E.; Bean, Jacob L.; Beatty, Thomas G.; Bell, Taylor J.; Benneke, Björn; Berta-Thompson, Zachory K.; Carter, Aarynn L.; Crossfield, Ian J. M.; Espinoza, Néstor; Feinstein, Adina D.; Fortney, Jonathan J. (2023)."Identification of carbon dioxide in an exoplanet atmosphere".Nature.614(7949): 649–652.arXiv:2208.11692.Bibcode:2023Natur.614..649J.doi:10.1038/s41586-022-05269-w.PMC9946830.PMID36055338.
  88. ^abBell, Taylor J.; Welbanks, Luis; Schlawin, Everett; Line, Michael R.; Fortney, Jonathan J.; Greene, Thomas P.; Ohno, Kazumasa; Parmentier, Vivien; Rauscher, Emily; Beatty, Thomas G.; Mukherjee, Sagnick; Wiser, Lindsey S.; Boyer, Martha L.; Rieke, Marcia J.; Stansberry, John A. (7 Sep 2023). "Methane Throughout the Atmosphere of the Warm Exoplanet WASP-80b".Nature.623(7988): 709–712.arXiv:2309.04042.Bibcode:2023Natur.623..709B.doi:10.1038/s41586-023-06687-0.PMID37993572.S2CID261660354.
  89. ^Xue, Qiao; Bean, Jacob L.; Zhang, Michael; Welbanks, Luis; Lunine, Jonathan; August, Prune (2024)."JWST Transmission Spectroscopy of HD 209458b: A Supersolar Metallicity, a Very Low C/O, and No Evidence of CH4,HCN, or C2H2".The Astrophysical Journal Letters.963(1): L5.arXiv:2310.03245.Bibcode:2024ApJ...963L...5X.doi:10.3847/2041-8213/ad2682.
  90. ^Constantinou, Savvas; Madhusudhan, Nikku (2022-08-01)."Characterizing atmospheres of cloudy temperate mini-neptunes with JWST".Monthly Notices of the Royal Astronomical Society.514(2): 2073–2091.arXiv:2205.01690.Bibcode:2022MNRAS.514.2073C.doi:10.1093/mnras/stac1277.ISSN0035-8711.
  91. ^Madhusudhan, Nikku; Nixon, Matthew C.; Welbanks, Luis; Piette, Anjali A. A.; Booth, Richard A. (2020-03-01)."The Interior and Atmosphere of the Habitable-zone Exoplanet K2-18b".The Astrophysical Journal.891(1): L7.arXiv:2002.11115.Bibcode:2020ApJ...891L...7M.doi:10.3847/2041-8213/ab7229.ISSN0004-637X.
  92. ^Madhusudhan, Nikku; Sarkar, Subhajit; Constantinou, Savvas; Holmberg, Måns; Piette, Anjali A. A.; Moses, Julianne I. (2023-10-01)."Carbon-bearing Molecules in a Possible Hycean Atmosphere".The Astrophysical Journal.956(1): L13.arXiv:2309.05566.Bibcode:2023ApJ...956L..13M.doi:10.3847/2041-8213/acf577.ISSN0004-637X.
  93. ^Wright, Katherine (2023-10-13)."The Skinny on Detecting Life with the JWST".Physics.16:178.Bibcode:2023PhyOJ..16..178W.doi:10.1103/Physics.16.178.S2CID264332900.
  94. ^Miles, Brittany E.; Skemer, Andrew J. I.; Morley, Caroline V.; Marley, Mark S.; Fortney, Jonathan J.; Allers, Katelyn N.; Faherty, Jacqueline K.; Geballe, Thomas R.; Visscher, Channon; Schneider, Adam C.; Lupu, Roxana; Freedman, Richard S.; Bjoraker, Gordon L. (2020-08-01)."Observations of Disequilibrium CO Chemistry in the Coldest Brown Dwarfs".The Astronomical Journal.160(2): 63.arXiv:2004.10770.Bibcode:2020AJ....160...63M.doi:10.3847/1538-3881/ab9114.ISSN0004-6256.
  95. ^Showman, A. P.; Wordsworth, R. D.; Merlis, T. M.; Kaspi, Y. (2013). "Atmospheric Circulation of Terrestrial Exoplanets".Comparative Climatology of Terrestrial Planets.p. 277.arXiv:1306.2418.Bibcode:2013cctp.book..277S.doi:10.2458/azu_uapress_9780816530595-ch12.ISBN978-0-8165-3059-5.S2CID52494412.
  96. ^5400mph winds discovered hurtling around planet outside solar system,Science Daily, November 13, 2015
  97. ^Louden, Tom; Wheatley, Peter J. (2015). "SPATIALLY RESOLVED EASTWARD WINDS AND ROTATION OF HD 189733b".The Astrophysical Journal.814(2): L24.arXiv:1511.03689.Bibcode:2015ApJ...814L..24L.doi:10.1088/2041-8205/814/2/L24.
  98. ^Kreidberg, Laura; Line, Michael R.; Thorngren, Daniel; Morley, Caroline V.; Stevenson, Kevin B. (2018-05-01)."Water, High-altitude Condensates, and Possible Methane Depletion in the Atmosphere of the Warm Super-Neptune WASP-107b".The Astrophysical Journal.858(1): L6.arXiv:1709.08635.Bibcode:2018ApJ...858L...6K.doi:10.3847/2041-8213/aabfce.ISSN0004-637X.
  99. ^Grant, David; Lewis, Nikole K.; Wakeford, Hannah R.; Batalha, Natasha E.; Glidden, Ana; Goyal, Jayesh; Mullens, Elijah; MacDonald, Ryan J.; May, Erin M.; Seager, Sara; Stevenson, Kevin B.; Valenti, Jeff A.; Visscher, Channon; Alderson, Lili; Allen, Natalie H. (2023-10-01)."JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b".The Astrophysical Journal.956(2): L29.arXiv:2310.08637.Bibcode:2023ApJ...956L..32G.doi:10.3847/2041-8213/acfc3b.ISSN0004-637X.
  100. ^abcHelling, Ch.; Gourbin, P.; Woitke, P.; Parmentier, V. (2019-06-01)."Sparkling nights and very hot days on WASP-18b: the formation of clouds and the emergence of an ionosphere".Astronomy and Astrophysics.626:A133.arXiv:1901.08640.Bibcode:2019A&A...626A.133H.doi:10.1051/0004-6361/201834085.ISSN0004-6361.
  101. ^Kuzuhara, M.; Tamura, M.; Kudo, T.; Janson, M.; Kandori, R.; Brandt, T. D.; Thalmann, C.; Spiegel, D.; Biller, B.; Carson, J.; Hori, Y.; Suzuki, R.; Burrows, A.; Henning, T.; Turner, E. L. (2013-09-01)."Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504".The Astrophysical Journal.774(1): 11.arXiv:1307.2886.Bibcode:2013ApJ...774...11K.doi:10.1088/0004-637X/774/1/11.ISSN0004-637X.
  102. ^Manjavacas, Elena; Karalidi, Theodora; Vos, Johanna M.; Biller, Beth A.; Lew, Ben W. P. (2021-11-01)."Revealing the Vertical Cloud Structure of a Young Low-mass Brown Dwarf, an Analog to the β-Pictoris b Directly Imaged Exoplanet, through Keck I/MOSFIRE Spectrophotometric Variability".The Astronomical Journal.162(5): 179.arXiv:2107.12368.Bibcode:2021AJ....162..179M.doi:10.3847/1538-3881/ac174c.ISSN0004-6256.
  103. ^Aglyamov, Yury S.; Lunine, Jonathan; Becker, Heidi N.; Guillot, Tristan; Gibbard, Seran G.; Atreya, Sushil; Bolton, Scott J.; Levin, Steven; Brown, Shannon T.; Wong, Michael H. (2021-02-01)."Lightning Generation in Moist Convective Clouds and Constraints on the Water Abundance in Jupiter".Journal of Geophysical Research: Planets.126(2): e06504.arXiv:2101.12361.Bibcode:2021JGRE..12606504A.doi:10.1029/2020JE006504.hdl:2027.42/166445.ISSN0148-0227.S2CID231728590.
  104. ^Ben-Yami, Maya; Madhusudhan, Nikku; Cabot, Samuel H. C.; Constantinou, Savvas; Piette, Anjali; Gandhi, Siddharth; Welbanks, Luis (2020-07-01)."Neutral Cr and V in the Atmosphere of Ultra-hot Jupiter WASP-121 b".The Astrophysical Journal.897(1): L5.arXiv:2006.05995.Bibcode:2020ApJ...897L...5B.doi:10.3847/2041-8213/ab94aa.ISSN0004-637X.
  105. ^Jiang, Zewen; Wang, Wei; Zhao, Gang; Zhai, Meng; Shi, Yaqing; Liu, Yujuan; Zhao, Jingkun; Chen, Yuqin (2023-06-01)."Detection of Rubidium and Samarium in the Atmosphere of the Ultrahot Jupiter MASCARA-4b".The Astronomical Journal.165(6): 230.arXiv:2304.04948.Bibcode:2023AJ....165..230J.doi:10.3847/1538-3881/accb54.ISSN0004-6256.
  106. ^Borsato, N. W.; Hoeijmakers, H. J.; Prinoth, B.; Thorsbro, B.; Forsberg, R.; Kitzmann, D.; Jones, K.; Heng, K. (2023-05-01)."The Mantis Network. III. Expanding the limits of chemical searches within ultra-hot Jupiters: New detections of Ca I, V I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b".Astronomy and Astrophysics.673:A158.arXiv:2304.04285.Bibcode:2023A&A...673A.158B.doi:10.1051/0004-6361/202245121.ISSN0004-6361.
  107. ^"New World of Iron Rain".Astrobiology Magazine.8 January 2003. Archived from the original on 2013-06-04.{{cite web}}:CS1 maint: unfit URL (link)
  108. ^Howell, Elizabeth (30 August 2013)On Giant Blue Alien Planet, It Rains Molten Glass.SPACE.com
  109. ^Raining Pebbles: Rocky Exoplanet Has Bizarre Atmosphere, Simulation Suggests.Science Daily. 1 October 2009
  110. ^Morgan, James (14 October 2013)'Diamond rain' falls on Saturn and Jupiter.BBC.
  111. ^Sanders, Robert (22 March 2010)Helium rain on Jupiter explains lack of neon in atmosphere.newscenter.berkeley.edu
  112. ^"Oxygen Is Not Definitive Evidence of Life on Extrasolar Planets".NAOJ.Astrobiology Web. 10 September 2015.Retrieved2015-09-11.
  113. ^Wordsworth, R.; Pierrehumbert, R. (2014). "Abiotic Oxygen-Dominated Atmospheres on Terrestrial Habitable Zone Planets".The Astrophysical Journal.785(2): L20.arXiv:1403.2713.Bibcode:2014ApJ...785L..20W.doi:10.1088/2041-8205/785/2/L20.S2CID17414970.
  114. ^Selsis, F.; Wordsworth, R. D.; Forget, F. (2011). "Thermal phase curves of nontransiting terrestrial exoplanets".Astronomy & Astrophysics.532:A1.arXiv:1104.4763.Bibcode:2011A&A...532A...1S.doi:10.1051/0004-6361/201116654.S2CID16696541.
  115. ^Benneke, B.; Seager, S. (2012). "Atmospheric Retrieval for Super-Earths: Uniquely Constraining the Atmospheric Composition with Transmission Spectroscopy".The Astrophysical Journal.753(2): 100.arXiv:1203.4018.Bibcode:2012ApJ...753..100B.doi:10.1088/0004-637X/753/2/100.S2CID15328948.
  116. ^abThe Mystery of Methane on Mars and Titan.Sushil K. Atreya,Scientific American.January 15, 2009.
  117. ^Exoplanet Biosignature Gases.Sarah Seager.
  118. ^Is There a Methane Habitable Zone?Paul Scott Anderson,Universe Today.15 November 2011
  119. ^Could Alien Life Exist in the Methane Habitable Zone?.Keith Cooper,Astrobiology Magazine.November 16, 2011.
  120. ^Recovery and Utilization of Extraterrestrial ResourcesArchived2016-12-10 at theWayback Machine(PDF). NASA Scientific and Technical Information Program. January 2004.
  121. ^NASA Tests Methane-Powered Engine Components for Next Generation Landers.NASA News. October 28, 2015.
  122. ^Cain, Fraser (March 12, 2013)."Atmosphere of Mercury".Universe Today.Archivedfrom the original on April 19, 2012.RetrievedApril 7,2013.
  123. ^Donahue, T.M.; Hodges, R.R. (1993). "Venus methane and water".Geophysical Research Letters.20(7): 591–594.Bibcode:1993GeoRL..20..591D.doi:10.1029/93GL00513.hdl:2027.42/94590.
  124. ^Stern, S.A. (1999). "The Lunar atmosphere: History, status, current problems, and context".Rev. Geophys.37(4): 453–491.Bibcode:1999RvGeo..37..453S.CiteSeerX10.1.1.21.9994.doi:10.1029/1999RG900005.S2CID10406165.
  125. ^"Mars Express confirms methane in the Martian atmosphere".European Space Agency.Archivedfrom the original on February 24, 2006.RetrievedMarch 17,2006.
  126. ^Schirber, Michael (January 15, 2009)."Methane-spewing Martians?".NASA's Astrobiology Magazine. Archived from the original on 2012-04-09.{{cite web}}:CS1 maint: unfit URL (link)
  127. ^Atkinson, Nancy (September 11, 2012)."Methane on Mars may be result of electrification of dust devils".Universe Today.
  128. ^"Methane on Mars is not an indication of life: UV radiation releases methane from organic materials from meteorites".Max-Planck-Gesellschaft. May 31, 2012.
  129. ^Mars Vents Methane in What Could Be Sign of Life,Washington Post, January 16, 2009
  130. ^Tenenbaum, David (June 9, 2008)."Making Sense of Mars Methane".Astrobiology Magazine.Archived from the original on September 23, 2008.RetrievedOctober 8,2008.{{cite web}}:CS1 maint: unfit URL (link)
  131. ^Steigerwald, Bill (January 15, 2009)."Martian Methane Reveals the Red Planet is not a Dead Planet".NASA's Goddard Space Flight Center.NASA.Archivedfrom the original on January 17, 2009.
  132. ^"Mars Curiosity Rover News Telecon -November 2, 2012".
  133. ^Kerr, Richard A. (November 2, 2012)."Curiosity Finds Methane on Mars, or Not".Science.RetrievedNovember 3,2012.
  134. ^Webster, Guy; Neal-Jones, Nancy; Brown, Dwayne (16 December 2014)."NASA Rover Finds Active and Ancient Organic Chemistry on Mars".NASA.Retrieved16 December2014.
  135. ^Chang, Kenneth (16 December 2014)."'A Great Moment': Rover Finds Clue That Mars May Harbor Life ".The New York Times.Retrieved16 December2014.
  136. ^Webster, Christopher R. (23 January 2015)."Mars methane detection and variability at Gale crater"(PDF).Science.347(6220): 415–417.Bibcode:2015Sci...347..415W.doi:10.1126/science.1261713.PMID25515120.S2CID20304810.
  137. ^"Jupiter Fact Sheet".NASA.
  138. ^"Saturn Fact Sheet".NASA.
  139. ^Waite, Jack Hunter Jr.; Combi, M. R.; Ip, W. H.; Cravens, T. E.; McNutt Jr., R. L.; Kasprzak, W.; et al. (March 2006). "Cassini ion and neutral mass spectrometer: Enceladus plume composition and structure".Science.311(5766): 1419–22.Bibcode:2006Sci...311.1419W.doi:10.1126/science.1121290.PMID16527970.S2CID3032849.
  140. ^ Niemann, HB; Atreya, SK; Bauer, SJ; Carignan, GR; Demick, JE; Frost, RL; et al. (2005). "The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe".Nature.438(7069): 779–784.Bibcode:2005Natur.438..779N.doi:10.1038/nature04122.hdl:2027.42/62703.PMID16319830.S2CID4344046.
  141. ^McKay, Chris (June 8, 2010)."Have We Discovered Evidence For Life On Titan".SpaceDaily.RetrievedJune 10,2010.
  142. ^Grossman, Lisa (March 17, 2011)."Seasonal methane rain discovered on Titan".Wired.
  143. ^Dyches, Preston; Zubritsky, Elizabeth (October 24, 2014)."NASA Finds Methane Ice Cloud in Titan's Stratosphere".NASA.RetrievedOctober 31,2014.
  144. ^Zubritsky, Elizabeth; Dyches, Preston (October 24, 2014)."NASA Identifies Ice Cloud Above Cruising Altitude on Titan".NASA.RetrievedOctober 31,2014.
  145. ^"Uranus Fact Sheet".NASA.
  146. ^"Neptune Fact Sheet".NASA.
  147. ^Shemansky, D. F.; Yelle, R. V.; Linick, J. L.; Lunine, J. E.; Dessler, A. J.; Donahue, T. M.; et al. (December 15, 1989). "Ultraviolet Spectrometer Observations of Neptune and Triton".Science.246(4936): 1459–1466.Bibcode:1989Sci...246.1459B.doi:10.1126/science.246.4936.1459.PMID17756000.S2CID21809358.
  148. ^Miller, Ron;Hartmann, William K. (2005).The Grand Tour: A Traveler's Guide to the Solar System(3rd ed.). Thailand: Workman Publishing. pp. 172–73.ISBN978-0-7611-3547-0.
  149. ^Owen, T. C.; Roush, T. L.; Cruikshank, D. P.; Elliot, J. L.; Young, L. A.; De Bergh, C.; et al. (1993)."Surface Ices and the Atmospheric Composition of Pluto".Science.261(5122): 745–748.Bibcode:1993Sci...261..745O.doi:10.1126/science.261.5122.745.PMID17757212.S2CID6039266.
  150. ^"Pluto".SolStation.2006.RetrievedMarch 28,2007.
  151. ^Sicardy, B; Bellucci, A; Gendron, E; Lacombe, F; Lacour, S; Lecacheux, J; et al. (2006). "Charon's size and an upper limit on its atmosphere from a stellar occultation".Nature.439(7072): 52–4.Bibcode:2006Natur.439...52S.doi:10.1038/nature04351.hdl:11336/39754.PMID16397493.S2CID4411478.
  152. ^"Gemini Observatory Shows That" 10th Planet "Has a Pluto-Like Surface".Gemini Observatory.2005.RetrievedMay 3,2007.
  153. ^Mumma, M.J.; Disanti, M.A.; Dello Russo, N.; Fomenkova, M.; Magee-Sauer, K.; Kaminski, C.D.; Xie, D.X. (1996). "Detection of Abundant Ethane and Methane, Along with Carbon Monoxide and Water, in Comet C/1996 B2 Hyakutake: Evidence for Interstellar Origin".Science.272(5266): 1310–1314.Bibcode:1996Sci...272.1310M.doi:10.1126/science.272.5266.1310.PMID8650540.S2CID27362518.
  154. ^Battersby, Stephen (February 11, 2008)."Organic molecules found on alien world for first time".
  155. ^Choi, Charles M. (September 17, 2012)."Meteors might add methane to exoplanet atmospheres".NASA's Astrobiology Magazine. Archived from the original on June 2, 2013.RetrievedMarch 25,2018.{{cite web}}:CS1 maint: unfit URL (link)
  156. ^Lacy, J. H.; Carr, J. S.; Evans, N. J., I.; Baas, F.; Achtermann, J. M.; Arens, J. F. (1991). "Discovery of interstellar methane – Observations of gaseous and solid CH4absorption toward young stars in molecular clouds ".The Astrophysical Journal.376:556.Bibcode:1991ApJ...376..556L.doi:10.1086/170304.{{cite journal}}:CS1 maint: multiple names: authors list (link)
  157. ^Jørgensen, Uffe G. (1997),"Cool Star Models",in van Dishoeck, Ewine F. (ed.),Molecules in Astrophysics: Probes and Processes,International Astronomical Union Symposia. Molecules in Astrophysics: Probes and Processes, vol. 178, Springer Science & Business Media, p. 446,ISBN978-0792345381.

Further reading

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