Jump to content

2I/Borisov

From Wikipedia, the free encyclopedia

2I/Borisov
Borisov in October 2019[a]
Discovery
Discovered byGennadiy Borisov
Discovery siteMARGO observatory,Nauchnyy, Crimea
Discovery date30 August 2019
Earliestprecovery:
13 December 2018
Orbital characteristics
Epoch5 January 2020[3]
Observation arc389 days
Number of
observations		1191
Perihelion2.00662±0.00002AU
Semi-major axis−0.85132±0.00007AU[b]
Eccentricity3.3570±0.0002(JPL)
3.357(MPC)[4]
Inclination44.0535°±0.0001°
308.1500°±0.0003°
Argument of
periapsis		209.1244°±0.0004°
Last perihelion8 December 2019[3][4][5]
Next perihelioninterstellar object
EarthMOID1.09302AU
JupiterMOID2.388 AU
Physical characteristics
Dimensions≤ 0.5 km[6](for analbedoof 0.04)
≤ 0.4 km[7]

2I/Borisov,originally designatedC/2019 Q4 (Borisov),[8]is the first observedrogue cometand the second observed interstellar interloper afterʻOumuamua.[9][10]It was discovered by theCrimeanamateur astronomerand telescope makerGennadiy Borisovon 29 August 2019UTC(30 Augustlocal time).[11][12]

2I/Borisov has aheliocentricorbital eccentricityof 3.36 and is not bound to the Sun.[13]The comet passed through theeclipticof the Solar System at the end of October 2019, and made its closest approach to the Sun at just over2AUon 8 December 2019.[3][14]The comet passed closest to Earth on 28 December 2019.[15]In November 2019, astronomers fromYale Universitysaid that the comet's tail was 14 times the size of Earth, and stated, "It's humbling to realize how small Earth is next to this visitor from another solar system."[16]In the middle of March, 2020, the comet was observed to fragment;[17]and later, in April, even more evidence of fragmentation was reported.[18][19][20][dubious–discuss]

Nomenclature

[edit]

The comet is formally called "2I/Borisov" by theInternational Astronomical Union(IAU), with "2I" or "2I/2019 Q4" being its designation and "Borisov" being its name, but is sometimes referred to as "Comet Borisov", especially in the popular press.[c]As the second observed interstellar interloper after1I/ʻOumuamua,it was given the "2I"designation,where "I" stands for interstellar.[21][8]The name Borisov follows the tradition of naming comets after their discoverers. Before final designation as 2I/Borisov, the object was referred to by other names:

  • Early orbit solutions suggested that the comet could be anear-Earth objectand was thus listed onIAU'sMinor Planet Center's (MPC)Near-Earth Object Confirmation Page(NEOCP) as gb00234.[22]
  • Further refinements after thirteen days of observation made clear the object was a hyperbolic comet, and it was given the designation C/2019 Q4 (Borisov) by the Minor Planet Center on 11 September 2019.[23]A number of other astronomers includingDavide Farnocchia,Bill Gray (astronomer),andDavid Tholenconcluded that the comet was interstellar.[23]
  • On 24 September 2019 the IAU announced that the Working Group for Small Body Nomenclature kept the name Borisov giving the comet the interstellar designation of 2I/Borisov, formally announcing the comet was indeed interstellar.[21][8]

Characteristics

[edit]
In this observation, the NASA/ESA Hubble Space Telescope revisited the comet shortly after its closest approach to the Sun in December 2019.
External videos
video iconInterstellar comet 2I/Borisov at perihelion (8 December 2019).

Unlike ʻOumuamua, which had anasteroidalappearance, 2I/Borisov's nucleus is surrounded by acoma,a cloud of dust and gas.[24]

Comet 2I/Borisov and a distant galaxy (2MASX J10500165-0152029[25]) in November 2019.[26]

Size and shape

[edit]

Early estimates of nucleus 2I/Borisov diameter have ranged from1.4 to 16 km.[27][28]2I/Borisov has, unlike Solar System comets, noticeably shrunk during Solar System flyby, losing at least 0.4% of its mass beforeperihelion.[7]Also, the amplitude of non-gravitational acceleration place an upper limit of 0.4 km on nucleus size, consistent with a previousHubble Space Telescopeupper limit of 0.5 km.[6]The comet did not come much closer to Earth than 300 million km, which prevents using radar to directly determine its size and shape. This could be done using theoccultationof a star by 2I/Borisov but an occultation would be difficult to predict, requiring a precise determination of its orbit, and the detection would necessitate a network of small telescopes.[29]

Rotation

[edit]

A study using observations from Hubble could not find a variation in the light curve. According to this study the rotational period must be larger than 10 hours.[30]A study withCSA'sNEOSSatfound a period of 13.2 ± 0.2 days, which is unlikely to be the nuclear spin.[31]Monte Carlosimulations based on the available orbit determinations suggest that the equatorial obliquity of 2I/Borisov could be about 59 degrees or 90 degrees, the latter is favored for the latest orbit determination.[32]

Chemical makeup and nucleus structure

[edit]

David JewittandJane Luuestimate from the size of its coma the comet is producing 2 kg/s of dust and is losing 60 kg/s of water. They extrapolate that it became active in June 2019 when it was between 4 and 5aufrom the Sun.[6]A search of image archives foundprecoveryobservations of 2I/Borisov as early as 13 December 2018, but not on 21 November 2018, indicating it became active between these dates.[33]

2I/Borisov's composition appears uncommon yet not unseen in Solar System comets, being relatively depleted in water anddiatomic carbon(C2), but enriched incarbon monoxideandamines(R-NH2).[34]The molar ratio of carbon monoxide to water in 2I/Borisov tail is 35–105%, resembling the unusual blue-tailed cometC/2016 R2 (PANSTARRS)in contrast to the average ratio of 4% for solar system comets.[35]

The 2I/Borisov has also produced a minor amount of neutral nickel emission attributed to an unknown volatile compound of nickel.[36]The nickel to iron abundance ratio is similar to Solar System comets.[37]

Trajectory

[edit]
Trajectory across sky in cylindrical coordinates, with 30 August 2019 discovery position along with precovery positions marked back to 13 December 2018 which help narrow down the incoming trajectory
Interstellar velocity inbound ()[d]
Object Velocity
1I/2017 U1 (ʻOumuamua) 26.33 km/s
5.55 AU/yr[38]
2I/2019 Q4 (Borisov) 32.2 km/s
6.79 AU/yr[39]

As seen from Earth, the comet was in the northern sky from September until mid-November. It crossed the ecliptic plane on 26 October near the starRegulus,[40]and thecelestial equatoron 13 November 2019, entering the southern sky. On 8 December 2019, the comet reachedperihelion(closest approach to the Sun)[3]and was near the inner edge of the asteroid belt. In late December, it made its closest approach to Earth,[11][14]1.9au,and had a solar elongation of about 80°.[5]Due to its 44°orbital inclination,2I/Borisov did not make any notable close approaches to the planets.[3]2I/Borisov entered the Solar System from the direction ofCassiopeianear the border withPerseus.This direction indicates that it originates from thegalactic plane,rather than from thegalactic halo.[39][41]It will leave the Solar System in the direction ofTelescopium.[39][41]In interstellar space, 2I/Borisov takes roughly9000years to travel alight-yearrelative to the Sun.[e]

2I/Borisov's trajectory is extremelyhyperbolic,having anorbital eccentricityof 3.36.[3][4]This is much higher than the 300+ known weaklyhyperbolic comets,with heliocentric eccentricities just over 1, and even ʻOumuamua with an eccentricity of 1.2.[42][f]2I/Borisov also has ahyperbolic excess velocity() of32 km/s,much higher than what could be explained by perturbations, which could produce velocities when approaching an infinite distance from the Sun of less than a few km/s.[43]These two parameters are important indicators of 2I/Borisov's interstellar origin.[39][44]For comparison, theVoyager 1spacecraft, which is leaving the Solar System, is traveling at 16.9 km/s (3.57 AU/a).[45]2I/Borisov has a much larger eccentricity than ʻOumuamua due to its higher excess velocity and its significantly higher perihelion distance. At this larger distance, the Sun's gravity is less able to alter its path as it passes through the Solar System.[39]

2I/Borisov — orbit diagrams
Trajectory of Borisov (yellow) crossing the ecliptic plane; 'Oumuamua (red) shown for comparison
Borisov approaches the ecliptic plane between the orbits of Jupiter (pink) and Mars (orange)
Borisov's trajectory and position (white) as of 13 October 2019 (top view)

Observation

[edit]

Discovery

[edit]

The comet was discovered on 30 August 2019 byamateur astronomerGennadiy Borisovat his personal observatoryMARGOin Nauchnyy,Crimea,using a 0.65 meter telescope he designed and built himself.[46]The discovery has been compared to the discovery ofPlutobyClyde Tombaugh.[47]Tombaugh was also an amateur astronomer who was building his own telescopes, although he discovered Pluto usingLowell Observatory'sastrograph.At discovery, it was inbound3 AUfrom the Sun,3.7 AUfrom Earth, and had asolar elongationof 38°.[48]Borisov described his discovery thus:[49]

JPL Scout eccentricity ranges[50]
# of
observations 		Observation
arc (hours) 		Eccentricity
range
81 225 0.9–1.6
99 272 2.0–4.2
127 289 2.8–4.7
142 298 2.8–4.5
151 302 2.9–4.5

I observed it on August 29, but it was August 30Greenwich Time.[g]I saw a moving object in the frame, it moved in a direction that was slightly different from that ofmain asteroids.[h]I measured its coordinates and consulted theMinor Planet Centerdatabase. Turned out, it was a new object. Then I measured the near-Earth object rating,[i]it is calculated from various parameters, and it turned out to be 100% – in other words,dangerous.In such cases I must immediately post the parameters to the world webpage for confirmation of dangerous asteroids.[j]I posted it and wrote that the object was diffuse and that it was not an asteroid, but a comet.

2I/Borisov's interstellar origin required a couple of weeks to confirm. Early orbital solutions based on initial observations included the possibility that the comet could be a near-Earth object 1.4 AU from the Sun in an elliptical orbit with an orbital period of less than 1 year.[22]Later using 151 observations over 12 days,NASAJet Propulsion Laboratory'sScoutgave an eccentricity range of 2.9–4.5.[55]But with anobservation arcof only 12 days, there was still some doubt that it was interstellar because the observations were at a low solar elongation, which could introduce biases in the data such asdifferential refraction.Using large non-gravitational forces on the highly eccentric orbit, a solution could be generated with an eccentricity of about 1, an Earthminimum orbit intersection distance(MOID) of 0.34 AU (51 million km), and a perihelion at 0.90 AU around 30 December 2019.[56]However, based on available observations, the orbit could only be parabolic if non-gravitational forces (thrust due to outgassing) affected its orbit more than any previous comets.[57]Eventually with more observations the orbit converged to the hyperbolic solution that indicated an interstellar origin and non-gravitational forces could not explain the motion.[23]

Observation

[edit]
Hubble started observations of 2I/Borisov in October 2019, two months prior to the comet's closest approach to the Sun

The last observations were in July 2020, seven months after perihelion.[3]Observation of 2I/Borisov was aided by the fact that the comet was detected while inbound towards the Solar System. ʻOumuamua had been discovered as it was leaving the system, and thus could only be observed for 80 days before it was out of range. Because of its closest approach occurring near traditional year-end holidays, and the capability to have extended observations, some astronomers have called 2I/Borisov a "Christmas comet".[13][58]Observations using theHubble Space Telescopebegan on 12 October, when the comet moved far enough from the Sun to be safely observed by the telescope.[59]Hubble is less affected by the confounding effects of the coma than ground-based telescopes, which will allow it to study the rotationallight curveof 2I/Borisov's nucleus. This should facilitate an estimate of its size and shape.[needs update]

Comet chemistry

[edit]

A preliminary (low-resolution) visible spectrum of 2I/Borisov was similar to typicalOort Cloudcomets.[60][61]Itscolor indexesalso resemble the Solar System's long period comets.[6]Emissions at388nmindicated the presence ofcyanide(formula CN), which is typically the first detected in Solar System comets includingcomet Halley.[62]This was the first detection of gas emissions from an interstellar object.[63]The non-detection of diatomic carbon had also been reported in October 2019, with the ratio C2to CN being less than either 0.095[64]or 0.3.[65]The diatomic carbon was positively detected in November 2019, with measured C2to CN ratio of0.2±0.1.[66]This resembles a carbon-chain depleted group of comets, which are either Jupiter family comets[64]or rare blue-colored carbon monoxide comets exemplified byC/2016 R2.[67]By the end of November 2019, C2production had dramatically increased, and C2to CN ratio reached 0.61, along with appearance of bright amine (NH2) bands.[68]Atomic oxygen has also been detected, from this observers estimated an outgassing of water at a rate similar to Solar System comets.[69][70]Initially, neither water nor OH lines were directly detected[71]in September 2019. First unambiguous detection of OH lines was done 1 November 2019, and OH production peaked in early December 2019.[72]

Suspected nucleus fragmentation

[edit]

The comet did come within about 2 AU of the Sun, a distance at which many small comets have been found to disintegrate. The probability that a comet disintegrates strongly depends on the size of its nucleus; Guzik et al. estimated a probability of 10% that this would happen to 2I/Borisov.[15]Jewitt and Luu compared 2I/Borisov to C/2019 J2 (Palomar), another comet of similar size that disintegrated in May 2019 at a distance of 1.9 AU from the Sun.[73][6]In the event that the nucleus disintegrates, as is sometimes seen with small comets, Hubble can be used to study the evolution of the disintegration process.[74][6]

The severe outburst in February–March 2020, led to suspected "ongoing nucleus fragmentation" from the comet by 12 March.[17]Indeed, images from the Hubble Space Telescope taken on 30 March 2020 show a non-stellar core indicating that Comet 2I/Borisov has ejected sunward a large fragment.[18][19][75]The ejection is estimated to have begun around 7 March,[76]and may have occurred during one of the outbursts that occurred near that time.[77]The ejected fragment appeared to have vanished by 6 April 2020.[78]

A followup study, reported on 6 April 2020, observed only a single object, and noted that the fragment component had now disappeared.[78][20]Later analysis of the event showed the ejected dust and fragments have a combined mass of about 0.1% of total mass of nucleus, making the event a large outburst rather than fragmentation.[79]

Exploration

[edit]

The high hyperbolic excess velocity of 2I/Borisov of32 km/smakes it hard for a spacecraft to reach the comet with existing technology: According to a team of theInitiative for Interstellar Studies,a 202 kg (445 lb) spacecraft could theoretically have been sent in July 2018 to intercept 2I/Borisov using aFalcon Heavy-class launcher, or 765 kg (1687 lb) on aSpace Launch System(SLS)-class booster, but only if the object had been discovered much earlier than it was to meet the optimal launch date. Launches after the actual discovery date would eliminate the possibility to use Falcon Heavy-class rockets, requiringOberth maneuvresnear Jupiter and near the Sun and a larger launch vehicle. Even an SLS-class launcher would only have been able to deliver a 3 kg (6.6 lb) payload (such as aCubeSat) into a trajectory that would intercept 2I/Borisov in 2045 at a relative speed of34 km/s.[80]According to congressional testimony, NASA may need at least five years of preparation to launch such anintercepting mission.[81]

See also

[edit]

Notes

[edit]
  1. ^A photograph of Borisov's dust trail taken on12 October 2019with the UVIS F350LP channel ofWide Field Camera 3aboard theHubble Space Telescope.[1][2]At the time of this photograph, Borisov was 418 million km (260 million mi) fromEarth,similar to the average distance of theasteroid Ceresfrom theSun,and traveling at a velocity of 177,000 kilometres per hour (110,000 mph).[2]
  2. ^Objects with eccentricities greater than 1 will have a negative semimajor axis, giving them a positive orbital energy – the smaller the perihelion distance, and the larger above 1 the eccentricity is, the closer to 0 the semimajor axis value will be.
  3. ^This is the eighth comet discovered byGennadiy Borisov,and thus the ambiguous term "Comet Borisov" is not formally used here.
  4. ^For objects gravitationally bound to the Sun, velocities when approaching the equivalent of an infinite distance from the Sun should be less than a few kilometres per second. At its furthest distance from the Sun, Halley's comet moves≈ 1 km/swith respect to the Sun.
  5. ^299792.458 km/s/ 32.2 km/s = 9310 times slower than light.
  6. ^A comet with a parabolic trajectory (with an eccentricity of 1) would leave the Solar System in the direction it entered, having had its path altered by 180°. 2I/Borisov, with its higher eccentricity, has a more open trajectory and will have its path altered by only 34° as it passes through the Solar System.
  7. ^This is obviously a mistake: Crimea is 3 hoursaheadof Greenwich, so it was August 30 in Crimea when Borisov first observed the comet.[51]
  8. ^Of the 850,000 objects known to orbit the Sun, 756,000 (89%) aremain-beltasteroids.[52]
  9. ^The NEO rating calculates the probability that a new object is a near-Earth candidate.[53]
  10. ^This refers to the NEO Confirmation Page for confirming near-Earth objects and potentially hazardous objects.[54]

References

[edit]
  1. ^ National Aeronautics and Space Administration;European Space Agency;Jewitt, David(16 October 2019)."Comet 2I/Borisov Compass image".Hubblesite.Archivedfrom the original on 17 October 2019.Retrieved17 October2019.C/2019 Q4 (Borisov); HST WFC3/UVIS F350LP; Oct. 12, 2019
  2. ^ab National Aeronautics and Space Administration;European Space Agency;Jewitt, David(16 October 2019)."Hubble observes cirst confirmed interstellar comet".Hubblesite.Archivedfrom the original on 17 October 2019.Retrieved17 October2019.Hubble took a series of snapshots as the comet streaked along at 110,000 miles per hour. [...] The comet was 260 million miles from Earth when Hubble took the photo. [...] This Hubble image, taken on 12 October 2019 [...] reveals a central concentration of dust around the nucleus (which is too small to be seen by Hubble).
  3. ^abcdefg "C/2019 Q4 (Borisov)".JPL Small-Body Database Browser.Jet Propulsion Laboratory.Archivedfrom the original on 26 November 2019.Retrieved26 January2020.
  4. ^abc "2I/Borisov = C/2019 Q4 (Borisov)".Minor Planet Center.1 October 2019.Retrieved5 October2019.
  5. ^ab Gray, Bill (20 September 2019)."Pseudo-MPEC for gb00234".Project Pluto.Archivedfrom the original on 11 September 2019.Retrieved20 September2019.
  6. ^abcdef Jewitt, David; Luu, Jane (6 October 2019)."Initial Characterization of interstellar comet 2I/2019 Q4 (Borisov)".The Astrophysical Journal.886(2): L29.arXiv:1910.02547.Bibcode:2019ApJ...886L..29J.doi:10.3847/2041-8213/ab530b.S2CID203837079.
  7. ^abHui, Man-To; Ye, Quan-Zhi; Föhring, Dora; Hung, Denise; Tholen, David J. (2020). "Physical characterisation of interstellar comet 2I/2019 Q4 (Borisov)".arXiv:2003.14064[astro-ph.EP].
  8. ^abc "MPEC 2019-S72: 2I/Borisov = C/2019 Q4 (Borisov)".Minor Planet Center.Retrieved24 September2019.
  9. ^ "Interstellar comet with a familiar look".EurekAlert!(Press release). Astronomical Observatory,Jagiellonian University.14 October 2019.Retrieved14 October2014.
  10. ^ Grossman, Lisa (12 September 2019)."Astronomers have spotted a second interstellar object".Science News.Retrieved16 September2019.
  11. ^abOverbye, Dennis(7 December 2019)."The Interstellar Comet Has Arrived in Time for the Holidays".The New York Times.Retrieved7 December2019.This weekend an ice cube from beyond our solar system will makes its closest approach to the sun, trailing mystery and dust.
  12. ^ "Krymskiy astronom zayavil, chto otkrytaya im kometa izmenit nazvaniye"Крымский астроном заявил, что открытая им комета изменит название[Crimean astronomer says that the comet discovered by him will be renamed].RIA NovostiРИА Новости(in Russian). 16 September 2019. para. 5.Retrieved16 September2019.
  13. ^abSt. Fleur, Nicholas (24 December 2019)."Watching an interstellar comet and hoping for a bang".The New York Times.Retrieved28 December2019.Seeing comet Borisov won't be easy for the typical sky gazer, but astronomers still have a lot to learn from this extrasolar tourist.
  14. ^abCorum, Jonathan (7 December 2019)."Tracking comet Borisov".The New York Times.Retrieved7 December2019.
  15. ^ab Guzik, Piotr; Drahus, Michał; Rusek, Krzysztof; Waniak, Wacław; Cannizzaro, Giacomo; Pastor-Marazuela, Inés (2020). "Initial characterization of interstellar comet 2I/Borisov".Nature Astronomy.136:53–57.arXiv:1909.05851v3.Bibcode:2020NatAs...4...53G.doi:10.1038/s41550-019-0931-8.ISSN2397-3366.S2CID204509394.
  16. ^Shelton, Jim (26 November 2019)."New image offers close-up view of interstellar comet".Yale University.Retrieved7 December2019.
  17. ^abDrahus, Michal; et al. (12 March 2020)."ATel#1349: Multiple Outbursts of Interstellar Comet 2I/Borisov".The Astronomer's Telegram.Retrieved13 March2020.
  18. ^abJewitt, David; et al. (2 April 2020)."ATel #13611: Interstellar Object 2I/Borisov Double".The Astronomer's Telegram.Retrieved3 April2020.
  19. ^abBolin, Bryce T.; et al. (3 April 2020)."ATel #13613: Possible fragmentation of interstellar comet 2I/Borisov".The Astronomer's Telegram.Retrieved3 April2020.
  20. ^abSokol, Joshua (7 April 2020)."It came from outside our Solar system and now it's breaking up".The New York Times.Retrieved8 April2020.Comet Borisov, only the second interstellar object spotted by astronomers, shed at least one big chunk as it rounded our sun.
  21. ^ab Christensen, Lars Lindberg."Naming of new interstellar visitor: 2I/Borisov".International Astronomical Union(Press release).Retrieved24 September2019.
  22. ^ab Gray, Bill."Pseudo-MPEC for gb00234 (AutoNEOCP)".Project Pluto.Archived fromthe originalon 10 September 2019.Retrieved13 September2019.
  23. ^abc "Comet C/2019 Q4 (Borisov)".Minor Planet Center.Retrieved11 September2019.
  24. ^ Greskno, Michael (12 September 2019)."Bizarre comet from another star system just spotted".National Geographic.Archived fromthe originalon 12 September 2019.Retrieved25 September2019.
  25. ^Gohd, Chelsea (14 December 2019)."Interstellar comet Borisov shines in incredible new Hubble photos".Space.com.Retrieved21 January2020.
  26. ^"Hubble Watches Interstellar Comet Borisov Speed Past the Sun".www.spacetelescope.org.Retrieved16 December2019.
  27. ^ "Newly discovered comet is likely interstellar visitor".JPL / NASA.12 September 2019.
  28. ^Lee, Chien-Hsiu (11 December 2019)."FLAMINGOS-2 infrared photometry of 2I/Borisov".Research Notes of the AAS.3(12): 184.arXiv:1912.05628.Bibcode:2019RNAAS...3..184L.doi:10.3847/2515-5172/ab5f69.S2CID209324025.
  29. ^ Bamberger, Daniel; Wells, Guy (22 October 2019)."The difficulty of predicting stellar occultations by interstellar comet 2I/Borisov".Research Notes of the AAS.3(10): 159.Bibcode:2019RNAAS...3..159B.doi:10.3847/2515-5172/ab4efb.ISSN2515-5172.S2CID209959146.
  30. ^Bolin, Bryce T. (13 December 2019)."Constraints on the spin-pole orientation, jet morphology, and rotation of interstellar comet 2I/Borisov with deep HST imaging".Monthly Notices of the Royal Astronomical Society.497(4): 4031–4041.arXiv:1912.07386.doi:10.1093/mnras/staa2192.S2CID218595761.
  31. ^Gladman, Brett; Boley, Aaron; Balam, Dave (12 December 2019)."The inbound light curve of 2I/Borisov".Research Notes of the AAS.3(12): 187.Bibcode:2019RNAAS...3..187G.doi:10.3847/2515-5172/ab6085.ISSN2515-5172.S2CID216391537.
  32. ^de la Fuente Marcos, C.; de la Fuente Marcos, R. (1 November 2020)."Constraining the orientation of the spin axes of extrasolar minor bodies 1I/2017 U1 ('Oumuamua) and 2I/Borisov".Astronomy and Astrophysics.643:A18.arXiv:2009.08423.Bibcode:2020A&A...643A..18D.doi:10.1051/0004-6361/202037447.S2CID221761422.
  33. ^Ye, Quanzi; et al. (2020)."Pre-discovery activity of new interstellar comet 2I/Borisov beyond 5 AU".The Astronomical Journal.159(2): 77.arXiv:1911.05902.Bibcode:2020AJ....159...77Y.doi:10.3847/1538-3881/ab659b.S2CID208006384.
  34. ^Bodewits, D.; Noonan, J.W.; Feldman, P.D.; Bannister, M.T.; Farnocchia, D.; Harris, W.M.; et al. (2020). "The carbon monoxide-rich interstellar comet 2I/Borisov".Nature Astronomy.4(9): 867–871.arXiv:2004.08972.Bibcode:2020NatAs...4..867B.doi:10.1038/s41550-020-1095-2.S2CID215827703.
  35. ^Cordiner, M.A.; Milam, S.N.; Biver, N.;Bockelée-Morvan, D.;Roth, N.X.; Bergin, E.A.; et al. (2020). "Unusually high CO abundance of the first active interstellar comet".Nature Astronomy.4(9): 861–866.arXiv:2004.09586.Bibcode:2020NatAs...4..861C.doi:10.1038/s41550-020-1087-2.S2CID216036159.
  36. ^Guzik, Piotr; Drahus, Michał (2021), "Gaseous atomic nickel in the coma of interstellar comet 2I/Borisov",Nature,593(7859): 375–378,arXiv:2105.09305,Bibcode:2021Natur.593..375G,doi:10.1038/s41586-021-03485-4,PMID34012084,S2CID234777842
  37. ^Optim et al. 2021, Manfroid et al 2021
  38. ^ Gray, Bill (26 October 2017)."Pseudo-MPEC for A/2017 U1 (FAQ File)".Project Pluto.Retrieved26 October2017.
  39. ^abcde Gray, Bill."FAQ for C/2019 Q4 (Borisov)".Project Pluto.Retrieved25 September2019.
  40. ^"Comet 2I Borisov".spaceweathergallery.com.
  41. ^ab de León, J.; Licandro, J.; de la Fuente Marcos, C.; de la Fuente Marcos, R.; Lara, L. M.; Moreno, F.; et al. (30 April 2020)."Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4 m GTC and the 3.6 m TNG telescopes".Monthly Notices of the Royal Astronomical Society.495(2): 2053–2062.arXiv:2005.00786v1.Bibcode:2020MNRAS.495.2053D.doi:10.1093/mnras/staa1190.S2CID218486809.
  42. ^ "Search Engine: e > 1".JPL Small-Body Database.Jet Propulsion Laboratory.Archivedfrom the original on 25 September 2019.Retrieved25 September2019.
  43. ^ Siegel, Ethan (16 December 2017)."Why don't comets orbit the same way planets do?".Ask Ethan.Archivedfrom the original on 1 October 2019.Retrieved1 October2019.
  44. ^ "Interstellar Comet gb00234".Astronomer's Telegram.Archivedfrom the original on 12 September 2019.Retrieved12 September2019.
  45. ^ "Fast Facts".Jet Propulsion Laboratory.Voyager.Retrieved27 September2019.
  46. ^ King, Bob (11 September 2019)."Is another interstellar visitor headed our way?".Sky & Telescope.Retrieved12 September2019.
  47. ^ Нелюбин, Николай (13 September 2019).«Готовы открывать кометы бесплатно, лишь бы имя осталось». Российский астроном Геннадий Борисов о первой в истории человечества межзвёздной комете[ "We'll discover comets without pay, what matters is that the name lives on" — Russian astronomer Gennadiy Borisov on the first interstellar comet in the history of humankind.].Fontanka.ruФонтанка.ру(in Russian).Retrieved16 September2019.
  48. ^ Gray, Bill."Pseudo-MPEC for gb00234 (precovery-eph)".Project Pluto.Archivedfrom the original on 12 September 2019.Retrieved11 September2019.
  49. ^ Крымский астроном заявил, что открытая им комета изменит название[Crimean astronomer says that the comet discovered by him will be renamed.].RIA NovostiРИА Новости(in Russian). 16 September 2019. para. 5.Retrieved16 September2019.
  50. ^ "81 obs / 225 hours".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 8 September 2019.
    "99 obs / 272 hours".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 10 September 2019.
    "127 obs / 289 hours".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 11 September 2019.
    "142 obs / 298 hours".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 11 September 2019.
    "151 obs / 302 hours".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 11 September 2019.
  51. ^"Current local time in Crimea, Republic of, Russia".WorldTimeServer.com.23 May 2016.Retrieved15 August2023.
  52. ^"IAU Minor Planet Center".minorplanetcenter.net.Retrieved15 August2023.
  53. ^"Neo Rating".minorplanetcenter.net.Retrieved15 August2023.
  54. ^"The NEO Confirmation Page".www.minorplanetcenter.net.Retrieved15 August2023.
  55. ^ "with 151 obs".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 10 September 2019.Retrieved10 September2019– via archive.org.
    "alternate CENOS archival source".JPL CNEOS.Scout: gb00234. Archived fromthe originalon 11 September 2019 – via archive.today.
  56. ^ Gray, Bill (10 September 2019)."Is gb00234 an interstellar comet or asteroid?".Minor Planet Mailing List. Archived fromthe originalon 19 September 2019.Retrieved10 September2019.
  57. ^ Gray, Bill."Pseudo-MPEC for gb00234 (non-grav A1+A2)".Project Pluto.Archivedfrom the original on 11 September 2019.Retrieved11 September2019.
  58. ^ Overbye, Dennis(1 October 2019)."An interstellar comet, in time for the holidays".The New York Times.Retrieved2 October2019.On Dec. 7, the extrasolar comet now known as 2I/Borisov will make its closest approach to the sun.
  59. ^HST Weekly Observing Timeline(Report). Space Telescope Science Institute. 7 October 2019. Archived fromthe originalon 5 November 2019.Retrieved8 October2019.
  60. ^ "The Gran Telescopio Canarias (GTC) obtains the visible spectrum of C/2019 Q4 (Borisov), the first confirmed interstellar comet".Instituto de Astrofísica de Canarias.14 September 2019.Retrieved14 September2019.
  61. ^ de León, Julia; Licandro, Javier; Serra-Ricart, Miquel; Cabrera-Lavers, Antonio; Font Serra, Joan; Scarpa, Riccardo; de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (19 September 2019)."Interstellar Visitors: A physical characterization of comet C/2019 Q4 (Borisov) with OSIRIS at the 10.4 m GTC".Research Notes of the AAS.3(9): 131.Bibcode:2019RNAAS...3..131D.doi:10.3847/2515-5172/ab449c.ISSN2515-5172.S2CID204193392.
  62. ^ Fitzsimmons, Alan; Hainaut, Olivier; Meech, Karen; Jehin, Emmanuel; Moulane, Youssef; Opitom, Cyrielle; et al. (2 October 2019)."Detection of CN gas in interstellar object 2I/Borisov".The Astrophysical Journal.885(1): L9.arXiv:1909.12144v2.Bibcode:2019ApJ...885L...9F.doi:10.3847/2041-8213/ab49fc.S2CID202888942.
  63. ^"IAU Electronic Telegram No. 4670".Central Bureau for Astronomical Telegrams. Archived fromthe originalon 25 September 2019.Retrieved25 September2019.
  64. ^ab Kareta, Theodore; Andrews, Jennifer; Noonan, John W.; Harris, Walter M.; Smith, Nathan; O'Brien, Patrick; et al. (2020)."Carbon chain depletion of 2I/Borisov".The Astrophysical Journal.889(2): L38.arXiv:1910.03222.Bibcode:2020ApJ...889L..38K.doi:10.3847/2041-8213/ab6a08.S2CID203902806.
  65. ^ Opitom, C.; Fitzsimmons, A.; Jehin, E.; Moulane, Y.; Hainaut, O.; Meech, K. J.; et al. (20 October 2019). "2I/Borisov: A C2depleted interstellar comet ".Astronomy & Astrophysics.631:L8.arXiv:1910.09078.Bibcode:2019A&A...631L...8O.doi:10.1051/0004-6361/201936959.S2CID204801044.
  66. ^Lin, Hsing Wen; Lee, Chien-Hsiu; Gerdes, David W.; Adams, Fred C.; Becker, Juliette; Napier, Kevin; Markwardt, Larissa (2019)."Detection of diatomic carbon in 2I/Borisov".The Astrophysical Journal.889(2): L30.arXiv:1912.06161.doi:10.3847/2041-8213/ab6bd9.S2CID210472954.
  67. ^Venkataramani, Kumar; Ganesh, Shashikiran; Baliyan, Kiran S. (2020)."Ionic emissions in comet C/2016 R2 (Pan-STARRS)".Monthly Notices of the Royal Astronomical Society.495(4): 3559–3570.arXiv:2004.10266.Bibcode:2020MNRAS.495.3559V.doi:10.1093/mnras/staa1141.S2CID216056627.
  68. ^Bannister, Michele T.; Opitom, Cyrielle; Fitzsimmons, Alan; Moulane, Youssef; Jehin, Emmanuel; Seligman, Darryl; et al. (2020). "Interstellar comet 2I/Borisov as seen by MUSE: C2,NH2and red CN detections ".arXiv:2001.11605[astro-ph.EP].
  69. ^Starr, Michelle (30 October 2019)."That interstellar comet is carrying water from beyond our Solar System".ScienceAlert.com.Retrieved30 October2019.
  70. ^McKay, Adam J.; et al. (2020)."Detection of a Water Tracer in Interstellar Comet 2I/Borisov".The Astrophysical Journal.889(1): L10.arXiv:1910.12785.Bibcode:2020ApJ...889L..10M.doi:10.3847/2041-8213/ab64ed.S2CID204907108.
  71. ^Eubanks, T. M. (2019). "Is Interstellar Object 2I/Borisov a Stardust Comet? Predictions for the Post Perihelion Period".arXiv:1912.12730[astro-ph.EP].
  72. ^Xing, Zexi; Bodewits, Dennis; Noonan, John; Bannister, Michele T. (2020)."Water production rates and activity of interstellar comet 2I/Borisov".The Astrophysical Journal.893(2): L48.arXiv:2001.04865.Bibcode:2020ApJ...893L..48X.doi:10.3847/2041-8213/ab86be.S2CID210473691.
  73. ^ Jewitt, David; Luu, Jane (24 September 2019)."Disintegrating Inbound Long-period Comet C/2019 J2".The Astrophysical Journal Letters.883(2): L28.arXiv:1909.01964.Bibcode:2019ApJ...883L..28J.doi:10.3847/2041-8213/ab4135.ISSN2041-8205.S2CID202538864.
  74. ^ Jewitt, D.; Weaver, H. A.; Mutchler, M.; Agarwal, J.; Kim, Y.; Hui, M.-T. (25 September 2019)."Proposal 16009 - Interstellar Object C/2019 Q4"(PDF).Space Telescope Science Institute.Retrieved27 September2019.
  75. ^Starr, Michelle (3 April 2020)."Interstellar Comet 2I/Borisov really is breaking apart, according to new data".ScienceAlert.com.Retrieved3 April2020.
  76. ^"Possible fragmentation of interstellar comet 2I/Borisov".The Astronomer's Telegram.Retrieved3 April2020.
  77. ^"Multiple Outbursts of Interstellar Comet 2I/Borisov".The Astronomer's Telegram.Retrieved3 April2020.
  78. ^abZhang, Qicheng; et al. (6 April 2020)."ATel #16318: interstellar comet 2I/Borisov is single again".The Astronomer's Telegram.Retrieved6 April2020.
  79. ^Jewitt, David; Kim, Yoonyoung; Mutchler, Max; Weaver, Harold; Agarwal, Jessica; Hui, Man-To (2020)."Outburst and splitting of interstellar comet 2I/Borisov".The Astrophysical Journal.896(2): L39.arXiv:2006.01242.Bibcode:2020ApJ...896L..39J.doi:10.3847/2041-8213/ab99cb.S2CID219179411.
  80. ^ Hibberd, Adam; Perakis, Nikolaos; Hein, Andreas M. (13 September 2019). "Sending a spacecraft to interstellar comet C/2019 Q4 (Borisov)".arXiv:1909.06348[astro-ph.EP].
  81. ^ Threats from Space: A review of U.S. Government efforts to track and mitigate asteroids and meteors(PDF).Committee on Science, Space, and Technology (Report). Vol. (Part I and Part II). House of Representatives, One Hundred Thirteenth Congress, First Session. 19 March 2013. p. 147.Retrieved14 September2019.
[edit]
Wikimedia Commons has media related to2I/Borisov.
Retrieved from "https://en.wikipedia.org/w/index.php?title=2I/Borisov&oldid=1242262018"