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Pictor

Coordinates:Sky map05h00m00s,−50° 00′ 00″
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This article is about the constellation. For the Roman painter, seeGaius Fabius Pictor.For the Roman historian, seeQuintus Fabius Pictor.For the improved version ofPCPaint,seePictor Paint.

Pictor
Constellation
Pictor
List of stars in Pictor
AbbreviationPic
GenitivePictoris
Pronunciation/ˈpɪktər/,
genitive/pɪkˈtoʊrɪs/
SymbolismEasel
Right ascension4.53h-6.85h
Declination−43° - −64°
QuadrantSQ1
Area247 sq. deg. (59th)
Main stars3
Bayer/Flamsteed
stars		15
Stars withplanets6
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)1
Brightest starα Pic(3.30m)
Messier objects0
Meteor showers0
Bordering
constellations		Caelum
Carina
Columba
Dorado
Puppis
Volans
Visible at latitudes between +26° and −90°.
Best visible at 21:00 (9 p.m.) during the month ofJanuary.

Pictoris aconstellationin theSouthern Celestial Hemisphere,located between the starCanopusand theLarge Magellanic Cloud.Its name isLatinforpainter,and is an abbreviation of the older nameEquuleus Pictoris(the "painter'seasel"). Normally represented as an easel, Pictor was named by AbbéNicolas-Louis de Lacaillein the 18th century. The constellation's brightest star isAlpha Pictoris,awhite main-sequence stararound 97light-yearsaway from Earth. Pictor also hostsRR Pictoris,acataclysmic variable star systemthat flared up as anova,reachingapparent (visual) magnitude1.2 in 1925 before fading into obscurity.[a]

Pictor has attracted attention because of its second-brightest starBeta Pictoris,63.4 light-years distant from Earth, which is surrounded by an unusualdust diskrich incarbon,as well as twoexoplanets(extrasolar planets). Another five stars in the constellation have been observed to have planets. Among them isHD 40307,anorange dwarfthat has six planets orbiting it, one of which—HD 40307 g—is a potentialsuper-Earthin thecircumstellar habitable zone.Kapteyn's Star,the nearest star in Pictor to Earth, is ared dwarflocated 12.76 light-years away that was believed to have two super-Earths in orbit in 2014, but their existence of these planets was disproven in 2021.[4]Pictor Ais aradio galaxythat is shooting an 800,000 light-year longjet of plasmafrom asupermassive black holeat its centre. In 2006, agamma-ray burst—GRB 060729—was observed in Pictor, its extremely long X-rayafterglowdetectable for nearly two years.

History

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Early depiction c.1756, when known asle Chevalet et la Palette;CanopusofCarina(the keel, or the hull, of the ship) seen at upper right

The French astronomer AbbéNicolas-Louis de Lacaillefirst described Pictor asle Chevalet et la Palette(the easel and palette) in 1756,[5]after observing and cataloguing 10,000 southern stars during a two-year stay at theCape of Good Hope.[b]He devised 14 new constellations in uncharted regions of theSouthern Celestial Hemispherenot visible from Europe. All but one honored instruments that symbolised theAge of Enlightenment.[7]He gave these constellationsBayer designations,including ten stars in Pictor now named Alpha to Nu Pictoris.[c]He labelled the constellation Equuleus Pictorius on his 1763 chart,[8]the word "Equuleus" meaning small horse, or easel—perhaps from an old custom among artists of carrying a canvas on a donkey.[9]The German astronomerJohann Bodecalled it Pluteum Pictoris. The name was shortened to its current form in 1845 by the English astronomerFrancis Bailyon the suggestion of his countryman SirJohn Herschel.[5]

Characteristics

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Pictor is a small constellation bordered byColumbato the north,PuppisandCarinato the east,Caelumto the northwest,Doradoto the southwest andVolansto the south. The three-letter abbreviation for the constellation, as adopted by theInternational Astronomical Unionin 1922, is "Pic".[10]The official constellation boundaries, as set by Belgian astronomerEugène Delportein 1930, are defined by a polygon of 18 segments (illustrated in infobox). In theequatorial coordinate system,theright ascensioncoordinates of these borders lie between04h32.5mand06h52.0m,while thedeclinationcoordinates are between −42.79° and −64.15°.[11]Pictorculminateseach year at 9 p.m. on 17 March.[12]Its position in the far Southern Celestial Hemisphere means that the whole constellation is visible to observers south of latitude26°N,[13][d]and parts becomecircumpolarsouth of latitude 35°S.[14]

Features

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Stars

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See also:List of stars in Pictor
A photograph showing constellation Pictor as it can be seen by the naked eye (lines have been added that join up its three main stars). The bright star seen near Pictor is Canopus.

Pictor is a faint constellation; its three brightest stars can be seen near the prominentCanopus.[15]Within the constellation's borders, there are 49 stars brighter than or equal toapparent magnitude6.5.[e][13]Located about 97light-yearsaway from Earth,Alpha Pictorisis the brightest star in the constellation; it is awhite main-sequence starwith an apparent magnitude of 3.3,[17]andspectral typeA8VnkA6.[f][19]A rapidly spinning star with aprojected rotational velocityestimated at 206 km/s,[18]it has a shell of circumstellar gas.[20]Beta Pictorisis another white main sequence star of spectral type A6V and apparent magnitude 3.86. Located around 63.4 light-years distant from Earth,[21]it is a member of theBeta Pictoris moving group—a group of 17 star systems around 12 million years old moving through space together.[22]In 1984 Beta Pictoris was the first star discovered to have adebris disk.[23]Since then, anexoplanetabout eight times the mass of Jupiter has been discovered orbiting approximately 8astronomical units(AU) away from the star—a similar distance as that between the Sun and Saturn. TheEuropean Southern Observatory(ESO) confirmed its presence through the use ofdirect imagerywith theVery Large Telescopein late 2009.[24]

Gamma Pictorisis anorange giantof spectral type K1III that has swollen to 1.4 times the diameter of the Sun.[25]Shining with an apparent magnitude of 4.5, it lies 174 light-years distant from Earth.[26]HD 42540,called 47 Pictoris by American astronomerBenjamin Apthorp Gould,is a slightly cooler orange giant, with a spectral type of K2.5III and average magnitude 5.04.[27]It has also been suspected of being avariable star.[28]Lacaille mistakenly named this star Mu Doradus, but had recorded its Right Ascension one hour too low.[29]Lacaille named two neighbouring stars Eta Pictoris.[8][g]Eta2Pictoris,also known as HR 1663, is an orange giant of spectral type K5III and apparent magnitude 5.05. 474 light-years distant,[31]it has a diameter 5.6 times that of the Sun.[25]Eta1Pictoris,also known as HR 1649, is 85 light-years distant and is a main sequence star of spectral type F5V and visual magnitude 5.38.[32]A double star, it has a companion of magnitude 13; the two are separated by 11 arcseconds.[33]

Beta Pictoris Comparison[34]

Located about 1298 light-years from Earth,Delta Pictorisis aneclipsing binaryof theBeta Lyraetype.[35]Composed of two blue stars of spectral types B3III and O9V, the system has a period of 1.67 days, and is observed to dip from apparent magnitude 4.65 to 4.9.[36]The stars are oval-shaped as they are gravitationally distorted by each other.[37]TV Pictorisis aspectroscopic binarysystem composed of an A-type star and an F-type star which rotate around each other in a very close orbit. The latter star is elliptical in shape and itself varies in brightness.[38]The visual magnitude ranges between 7.37 and 7.53 every 20 hours.[39]

Aside from Beta, five other stars in Pictor are known to host planetary systems.AB Pictorisis aBY Draconis variablestar with a substellar companion that is either a large planet or abrown dwarf,which was discovered by direct imaging in 2005.[40]HD 40307is an orange main sequence star of spectral type K2.5V and apparent magnitude 7.17 located about 42 light-years away.Doppler spectroscopywith theHigh Accuracy Radial Velocity Planet Searcher(HARPS) indicates that HD 40307 is host to sixsuper-Earthplanets, one of which,HD 40307 g,lies in thecircumstellar habitable zoneof the star, and is not close enough to betidally locked(i.e. with the same face always facing the star), unlike the other planets in the same system, and many other planets which orbit close to their parent stars.[41]HD 41004is a complex binary system about 139 light-years distant. The primary is an orange dwarf of spectral type K1V orbited by a planet roughly 2.65 times the mass of Jupiter every 963 days, while the secondary is a red dwarf of spectral type M2V and orbited by a brown dwarf that is at least 19 times as massive as Jupiter. Both substellar components were discovered by doppler spectroscopy using theCORALIE spectrographin 2004 and 2002 respectively.[42]Kapteyn's Star,a nearbyred dwarfat the distance of 12.78 light-years, has a magnitude of 8.8. It has the largestproper motionof any star in the sky afterBarnard's Star.[43]Moving around the Milky Way in the opposite direction to most other stars, it may have originated in a dwarf galaxy that was merged into theMilky Way,with the main remnant being theOmega Centauriglobular cluster.[44]In 2014 analysis of the doppler variations of Kapteyn's Star with the HARPS spectrograph showed that it hosts two super-Earths—Kapteyn band Kapteyn c, but the existence of these exoplanet was disproven in 2021.[4]It is believed that these planets were actually just artifacts of the Kapteyn' star's rotation and activity.[4]

Located 1.5 degrees west southwest of Alpha,RR Pictorisis acataclysmic variablethat flared up as anova,reaching magnitude 1.2 on 9 June 1925.[43]Six months after its peak brightness, it had faded to be invisible to the unaided eye, and was magnitude 12.5 by 1975.[45]RR Pictorisis a close binary system composed of awhite dwarfand secondary star that orbit each other every 3.48 hours—so close that the secondary is filling up itsRoche lobewith stellar material, which is then transferred onto the first star'saccretion disk.Once this material reaches a critical mass, it ignites and the system brightens tremendously. Calculations from the orbital speed suggest the secondary star is not dense enough for its size to still be on themain sequence,so it also must have begun expanding and cooling already after its core ran out of hydrogen fuel.[46]The RR Pictoris system is estimated to lie around 1300 light-years distant from Earth.[47]

Deep-sky objects

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Composite image in X-rays byChandra X-ray Observatory(blue) and radiowaves byAustralia Telescope Compact Array(red) showing two lobes and ajet of plasmaemanating fromPictor A

NGC 1705is an irregular dwarf galaxy 17 million light-years from Earth. It is one of the most activestar forminggalaxies in the nearby universe, despite the fact that its rate of star formation peaked around 30 million years ago.[48]Pictor A,around 485 million light-years away, is a double-lobedradio galaxy[49]and a powerful source ofradio wavesin the Southern Celestial Hemisphere.[50]From asupermassive black holeat its centre, arelativistic jetshoots out to an X-ray hot spot 800,000 light years away.[51]SPT-CL J0546-5345is a massivegalaxy clusterlocated around 7 billion light-years away with a mass equivalent to approximately 800 trillion suns.[52]

GRB 060729was agamma-ray burstthat was first observed on 29 July 2006. It is likely the signal of atype Ic supernova—the core collapse of a massive star.[53]It was also notable for its extraordinarily long X-rayafterglow,detectable 642 days (nearly two years) after the original event.[54]The event was remote, with aredshiftof 0.54.[53]

See also

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Notes

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  1. ^Deneb,the19th-brightest starin the night sky, has a magnitude of 1.25.[1][2][3]
  2. ^His observatory was in a private house on the shores ofTable Bayin Cape Town.[6]
  3. ^He erred in naming the wrong star with the Greek letter epsilon, which is now not used.[8]
  4. ^While parts of the constellation technically rise above the horizon to observers between 26°N and47°N,stars within a few degrees of the horizon are to all intents and purposes unobservable.[13]
  5. ^Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies[16]
  6. ^The kA6 notation indicates a weaker than normalcalcium K-linein thespectrum.The 'n' following themain sequenceluminosity classof V indicates theabsorption linesin the spectrum are broad and nebulous, because of the rapid spin of the star.[18]
  7. ^Like Bayer, Lacaille would simply give two stars very close to each other the same designation with no modifier. It was left to later astronomers such as Gould to designate Eta1,Eta2etc.[30]

References

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Citations

  1. ^Chesneau, O.; Dessart, L.; Mourard, D.; Bério, Ph.; Buil, Ch.; Bonneau, D.; Borges Fernandes, M.; Clausse, J. M.; Delaa, O.; Marcotto, A.; Meilland, A.; Millour, F.; Nardetto, N.; Perraut, K.; Roussel, A.; Spang, A.; Stee, P.; Tallon-Bosc, I.; McAlister, H.; Ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J. (2010)."Time, spatial, and spectral resolution of the Hα line-formation region of Deneb and Rigel with the VEGA/CHARA interferometer".Astronomy and Astrophysics.521:A5.arXiv:1007.2095.Bibcode:2010A&A...521A...5C.doi:10.1051/0004-6361/201014509.S2CID10340205.
  2. ^ van de Kamp, P. (1953)."The Twenty Brightest Stars".Publications of the Astronomical Society of the Pacific.65(382): 30.Bibcode:1953PASP...65...30V.doi:10.1086/126523.
  3. ^Lamers, H. J. G. L. M.; Stalio, R.; Kondo, Y. (1978). "A study of mass loss from the mid-ultraviolet spectrum of α Cygni (A2 Ia), β Orionis (B8 Ia), and η Leonis (A0 Ib)".The Astrophysical Journal.223:207.Bibcode:1978ApJ...223..207L.doi:10.1086/156252.
  4. ^abcBortle, Anna; Fausey, Hallie; Ji, Jinbiao; Dodson-Robinson, Sarah; Delgado, Victor Ramirez; Gizis, John (2021-05-01)."A Gaussian Process Regression Reveals No Evidence for Planets Orbiting Kapteyn's Star".The Astronomical Journal.161(5): 230.arXiv:2103.02709.Bibcode:2021AJ....161..230B.doi:10.3847/1538-3881/abec89.ISSN0004-6256.
  5. ^abRidpath,Star TalesPictor.
  6. ^Warner 2002.
  7. ^Wagman 2003,pp. 6–7.
  8. ^abcWagman 2003,p. 246.
  9. ^Chartrand 1982,p. 176.
  10. ^Russell 1922,p. 469.
  11. ^IAU,The Constellations,Pictor.
  12. ^The Constellations: Part 2 Culmination Times.
  13. ^abcRidpath, Constellations: Lacerta–Vulpecula.
  14. ^Heifetz & Tirion 2007,p. 106.
  15. ^Moore,Stargazing2000,p. 118.
  16. ^The Bortle Dark-Sky Scale.
  17. ^SIMBAD Alpha Pictoris.
  18. ^abRoyer 2007.
  19. ^Gray 2006.
  20. ^Hempel 2003.
  21. ^SIMBAD Beta Pictoris.
  22. ^Zuckerman 2001.
  23. ^Smith & Terrile 1984.
  24. ^Lagrange 2010;ESO 2010.
  25. ^abPasinetti-Fracassini et al. 2001.
  26. ^SIMBAD Gamma Pictoris.
  27. ^SIMBAD HR 2196.
  28. ^AAVSO HR 2196.
  29. ^Harvard College Observatory 1883.
  30. ^Wagman 2003,p. 7.
  31. ^SIMBAD HR 1663.
  32. ^SIMBAD HR 1649.
  33. ^SIMBAD CD-49 1541B.
  34. ^"Beta Pictoris – Comparison".ESA/Hubble.Retrieved26 February2015.
  35. ^SIMBAD Delta Pictoris.
  36. ^Malkov & Oblak 2006.
  37. ^Cousins 1966.
  38. ^Pavlovski et al. 1998.
  39. ^AAVSO TV Pictoris.
  40. ^Chauvin 2005.
  41. ^Tuomi 2013.
  42. ^Zucker 2004.
  43. ^abMotz & Nathanson 1988,pp. 374–75.
  44. ^Kotoneva et al. 2005.
  45. ^Burham 2013,pp. 1460–62.
  46. ^Ribeiro 2006.
  47. ^Duerbeck 1981.
  48. ^Wilkins & Dunn 2006.
  49. ^NED Pictor A.
  50. ^Perley et al. 1997.
  51. ^ChandraPR.
  52. ^Ghosts of the Future.
  53. ^abCano et al. 2011.
  54. ^Grupe et al. 2010.

Sources

Online sources

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