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Piscis Austrinus

Coordinates:Sky map22h00m00s,−30° 00′ 00″
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Piscis Austrinus
Constellation
Piscis Austrinus
List of stars in Piscis Austrinus
AbbreviationPsA
GenitivePiscis Austrini
Pronunciation/ˈpaɪsɪsɒsˈtraɪnəs/or/ɒsˈtreɪlɪs/,genitive/ˈpaɪsɪsɒˈstraɪnaɪ/
SymbolismtheSouthernFish
Right ascension21h27m13.8661s–23h06m54.6033s[1]
Declination−24.8250446°–−36.4592972°[1]
QuadrantSQ4
Area245 sq. deg. (60th)
Main stars7
Bayer/Flamsteed
stars		21
Stars withplanets6
Stars brighter than 3.00m1
Stars within 10.00 pc (32.62 ly)3
Brightest starFomalhaut(α PsA) (1.16m)
Messier objects0
Meteor showers?
Bordering
constellations		Capricornus
Microscopium
Grus
Sculptor
Aquarius
Visible at latitudes between +55° and −90°.
Best visible at 21:00 (9 p.m.) during the month ofOctober.

Piscis Austrinusis aconstellationin thesouthern celestial hemisphere.The name isLatinfor "the southern fish", in contrast with the larger constellationPisces,which represents a pair of fish. Before the 20th century, it was also known asPiscis Notius.Piscis Austrinus was one of the 48 constellations listed by the 2nd-century astronomerPtolemy,and it remains one of the 88 modern constellations. The stars of the modern constellationGrusonce formed the "tail" of Piscis Austrinus. In 1597 (or 1598),Petrus Planciuscarved out a separate constellation and named it after the crane.

It is a faint constellation, containing only onestarbrighter than 4thmagnitude:Fomalhaut,which is 1st magnitude and the18th-brightest starin thenight sky.Fomalhaut is surrounded by acircumstellar disk,and possibly hosts a planet. Other objects contained within the boundaries of the constellation includeLacaille 9352,one of the brightestred dwarfstars in the night sky (though still too faint to see with the naked eye); andPKS 2155-304,aBL Lacertae objectthat is one of the optically brightestblazarsin the sky.

Origins

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Piscis Austrinus can be seen cut off at the bottom ofUrania's Mirror's 1825 depiction ofAquarius.Next to it is the obsolete constellationBallon Aerostatique.

Pisces Austrinus originated with the Babylonian constellation simply known as the Fish (MUL.KU).[2][3]Professor of astronomyBradley Schaeferhas proposed that ancient observers must have been able to see as far south asMu Piscis Austrinito define a pattern that looked like a fish.[4]Like many of Schaefer's proposals this is nothing new: mu PsA is explicitly mentioned in the Almagest and the constellation is definitely a takeover from ancient Babylon.[5]Along with the eagleAquilathe crow Corvus and water snake Hydra, Piscis Austrinus was introduced to the Ancient Greeks around 500 BCE; the constellations marked thesummerandwinter solstices,respectively.[6]

InGreek mythology,this constellation is known as the Great Fish and it is portrayed as swallowing the water being poured out by Aquarius, the water-bearer constellation. The two fish of the constellation Pisces are said to be the offspring of the Great Fish. InEgyptian mythology,this fish saved the life of the Egyptian goddessIsis,so sheplacedthis fish and its descendants into the heavens as constellations of stars.[7]In the 5th century BC, Greek historianCtesiaswrote that the fish was said to have lived in a lake nearBambycein Syria and had savedDerceto,daughter ofAphrodite,and for this deed was placed in the heavens. For this reason, fish were sacred and not eaten by many Syrians.[8]

Characteristics

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Piscis Austrinus is a constellation bordered byCapricornusto the northwest,Microscopiumto the southwest, Grus to the south,Sculptorto the east, and Aquarius to the north. Its recommended three-letter abbreviation, as adopted by theInternational Astronomical Unionin 1922, is "PsA".[9]Ptolemycalled the constellationIchthus Notios"Southern Fish" in hisAlmagest;this was Latinised to Piscis Notius and used by German celestial cartographersJohann BayerandJohann Elert Bode.[10]Bayer also called it Piscis Meridanus and Piscis Austrinus, while French astronomerNicolas-Louis de Lacaillecalled it Piscis Australis. EnglishAstronomer RoyalJohn Flamsteedwent with Piscis Austrinus, which was followed by most subsequently.[11]The official constellation boundaries, as set by Belgian astronomerEugène Delportein 1930, are defined by a polygon of four segments (illustrated in infobox). In theequatorial coordinate system,theright ascensioncoordinates of these borders lie between21h27.3mand23h06.5m,while thedeclinationcoordinates are between −24.83° and −36.46°.[12]The whole constellation is visible to observers south of latitude53°N.[13][a]

Features

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The constellation Piscis Austrinus as it can be seen by the naked eye

Stars

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See also:List of stars in Piscis Austrinus

Ancient astronomers counted twelve stars as belonging to Piscis Austrinus, though one was later incorporated into nearby Grus asGamma Gruis.[8]Other stars became part of Microscopium.[10]Bayer used theGreek lettersalphathroughmuto label the most prominent stars in the constellation. Ptolemy had catalogued Fomalhaut (Alpha Piscis Austrini) as belonging to both this constellation and Aquarius. Lacaille redrew the constellation as it was poorly visible from Europe, addingpi,and relabellinggamma,deltaandepsilonas epsilon,etaand gamma, respectively. However, Baily and Gould did not uphold these changes as Bayer's original chart was fairly accurate. Bode addedtauandupsilon.Flamsteed gave 24 starsFlamsteed designations,though the first four numbered became part of Microscopium.[11]Within the constellation's borders, there are 47 stars brighter than or equal toapparent magnitude6.5.[b][13]

Traditionally representing the mouth of the fish, Fomalhaut is the brightest star in the constellation and the19th-brightest starin the night sky, with an apparent magnitude of 1.16. Located 25.13 ± 0.09light-yearsaway, it is a whitemain-sequence starthat is 1.92 ± 0.02 times as massive and 16.63 ± 0.48 as luminous as the Sun.[15]Its companionFomalhaut bwas thought to be the firstextrasolar planetever detected by a visible light image, thanks to theHubble Space Telescope,but infrared observations have since retracted this claim: it is instead a spherical cloud of dust.TW Piscis Austrinican be seen close by and is possibly associated with Fomalhaut as it lies within a light-year of it. Of magnitude 6.5, it is a BY Draconis variable.[16]

The second-brightest star in the constellation,[17]Epsilon Piscis Austriniis a blue-white star of magnitude +4.17. Located 400 ± 20 light-years distant,[18]it is a blue-white main-sequence star 4.10 ± 0.19 times as massive as the Sun, and around 661 times as luminous.[19]

Beta,DeltaandZetaconstitute theTien Kang( "heavenly rope" ) inChina.[20]Beta is a white main-sequence star of apparent magnitude 4.29 that is of similar size and luminosity to Fomalhaut but five times as remote,[17]at around 143 ± 1 light-years distant from Earth.[21]Delta Piscis Austrini is a double star with components of magnitude 4.2 and 9.2.[16]The brighter is a yellow giant of spectral type G8 III.[22]It is ared clumpstar that is burning helium in its core.[23]It is 172 ± 2 light-years distant from Earth.[24]Zeta Piscis Austrini is an orange giant star of spectral type K1III that is located 413 ± 2 light-years distant from Earth.[25]It is a suspected variable star.[26]

S Piscis Austriniis a long-period Mira-type variable red giant which ranges between magnitude 8.0 and 14.5 over a period of 271.7 days, andV Piscis Austriniis a semi-regular variable ranging between magnitudes 8.0 and 9.0 over 148 days.[16]

Lacaille 9352 is a faintred dwarfstar of spectral type M0.5V that is just under half the Sun's diameter and mass.[27]A mere 10.74 light-years away, it is too dim to be seen with the naked eye at magnitude 7.34. In June 2020 twosuper-Earthplanets were discovered viaradial velocity method.

Exoplanets have been discovered in five other star systems in the constellation.HD 205739is a yellow-white main-sequence star of spectral type F7 V that has a planet around 1.37 times as massive as Jupiter orbiting it with a period of 279 days, and a suggestion of a second planet.[28]HD 216770is an orange dwarf accompanied by a Jupiter-like planet every 118 days.[29]HD 207832is a star of spectral type G5V with a diameter and mass about 90% of that of the Sun, and around 77% of its luminosity. Two gas giant planets with masses around 56% and 73% that of Jupiter were discovered in 2012 via the radial velocity method. With orbits of 162 and 1156 days, they average around 0.57 and 2.11 astronomical units away from their star.[30]

WASP-112andWASP-124are two sun-like stars that have planets discovered by transit.

Deep sky objects

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NGC 7172,NGC 7174andNGC 7314are three galaxies of magnitudes 11.9, 12.5 and 10.9, respectively.[16]NGC 7259is anotherspiral galaxy,which hosted asupernova—SN 2009ip—in 2009.

Atredshiftz = 0.116, theBL Lacertae objectPKS 2155-304is one of the brightestblazarsin the sky.[31]

See also

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Notes

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  1. ^While parts of the constellation technically rise above the horizon to observers between 53°N and65°N,stars within a few degrees of the horizon are to all intents and purposes unobservable.[13]
  2. ^Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.[14]

References

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  1. ^ab"The Constellations".International Astronomical Union.
  2. ^"Verities 4: Meta-Genetics".Ancestral Memories.Archived fromthe originalon 2017-12-12.Retrieved2017-12-12.
  3. ^Christoforou, Peter (24 April 2017)."Star Constellation Facts: Piscis Austrinus".Astronomy Trek.Retrieved5 April2018.
  4. ^Schaefer, Bradley E. (2002). "The latitude and epoch for the formation of the southern Greek constellations".Journal for the History of Astronomy.33, part 4 (113): 313–50.Bibcode:2002JHA....33..313S.doi:10.1177/002182860203300401.ISSN0021-8286.S2CID122459258.
  5. ^Hoffmann, Susanne M.; Elzner, Kay (2021).Wie der Löwe an den Himmel kam: auf den Spuren der Sternbilder.Mit Kosmos mehr entdecken. Stuttgart: Kosmos.ISBN978-3-440-17251-3.
  6. ^Frank, Roslyn M. (2015)."10: Origins of the" Western "Constellations".Handbook of Archaeoastronomy and Ethnoastronomy.New York City:Springer.pp. 147–163.Bibcode:2015hae..book.....R.
  7. ^Eratosthenes;Hyginus, C. Julius (1997).Star myths of the Greeks and Romans: a sourcebook containing the Constellations of Pseudo-Eratosthenes and the Poetic astronomy of Hyginus.Translated by Condos, Theony. Red Wheel/Weiser. pp.163–164.ISBN1-890482-93-5.
  8. ^abCondos, Theony (1997).Star Myths of the Greeks and Romans: A Sourcebook.Grand Rapids, Michigan: Phanes Press. pp. 163–65.ISBN9781609256784.
  9. ^Russell, Henry Norris(1922). "The new international symbols for the constellations".Popular Astronomy.30:469.Bibcode:1922PA.....30..469R.
  10. ^abRidpath, Ian."Piscis Austrinus - The Southern Fish".Star Tales.self-published.Retrieved23 March2019.
  11. ^abWagman, Morton (2003).Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others.Blacksburg, Virginia: The McDonald & Woodward Publishing Company. pp. 251–54, 457–58.ISBN978-0-939923-78-6.
  12. ^"Piscis Austrinus, constellation boundary".The Constellations.International Astronomical Union.Retrieved20 August2012.
  13. ^abcIan Ridpath."Constellations: Lacerta–Vulpecula".Star Tales.Self-published.Retrieved25 November2018.
  14. ^Bortle, John E. (February 2001)."The Bortle Dark-Sky Scale".Sky & Telescope.Sky Publishing Corporation.Retrieved25 November2018.
  15. ^Mamajek, Eric E. (August 2012). "On the Age and Binarity of Fomalhaut".Astrophysical Journal Letters.754(2): L20.arXiv:1206.6353.Bibcode:2012ApJ...754L..20M.doi:10.1088/2041-8205/754/2/L20.S2CID119191190.
  16. ^abcdMoore, Patrick (2011).Patrick Moore's Data Book of Astronomy.Cambridge University Press.p. 472.ISBN978-0521899352.
  17. ^abKaler, Jim (12 November 2009)."Beta PsA".Retrieved17 March2018.
  18. ^Brown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
  19. ^Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities".Astronomy & Astrophysics.537:A120.arXiv:1201.2052.Bibcode:2012A&A...537A.120Z.doi:10.1051/0004-6361/201117691.S2CID55586789.
  20. ^"Richard Hinckley Allen: Star Names — Their Lore and Meaning: Piscis Australis, the Southern Fish".
  21. ^van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction".Astronomy and Astrophysics.474(2): 653–64.arXiv:0708.1752.Bibcode:2007A&A...474..653V.doi:10.1051/0004-6361:20078357.S2CID18759600.
  22. ^Houk, Nancy (1979).Michigan catalogue of two-dimensional spectral types for the HD stars.Vol. 3. Ann Arbor, Michigan: Department of Astronomy, University of Michigan.Bibcode:1982mcts.book.....H.
  23. ^Liu, Y. J.; Zhao, G.; Shi, J. R.; Pietrzyński, G.; Gieren, W. (2007)."The abundances of nearby red clump giants".Monthly Notices of the Royal Astronomical Society.382(2): 553–66.Bibcode:2007MNRAS.382..553L.doi:10.1111/j.1365-2966.2007.11852.x.
  24. ^Brown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
  25. ^Brown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
  26. ^Demartino, Robert; Kocyla, Dennis; Predom, Christopher; Wetherbee, Edward (1996). "Accurate Positions Of Suspected Variable Stars Near The South Galactic Pole".Information Bulletin on Variable Stars.4322:1.Bibcode:1996IBVS.4322....1D.
  27. ^Rabus, Markus; Lachaume, Régis; Jordán, Andrés; Brahm, Rafael; Boyajian, Tabetha; Von Braun, Kaspar; Espinoza, Néstor; Berger, Jean-Philippe; Le Bouquin, Jean-Baptiste; Absil, Olivier (2019)."A discontinuity in the Teff–radius relation of M-dwarfs".Monthly Notices of the Royal Astronomical Society.484(2): 2674–2683.arXiv:1901.08077.Bibcode:2019MNRAS.484.2674R.doi:10.1093/mnras/sty3430.S2CID119189542.
  28. ^López-Morales, Mercedes; Butler, R. Paul; Fischer, Debra A.; Minniti, Dante; Shectman, Stephen A.; Takeda, Genya; Adams, Fred C.; Wright, Jason T.; Arriagada, Pamela (2008). "Two Jupiter-Mass Planets Orbiting HD 154672 and HD 205739".The Astronomical Journal.136(5): 1901–1905.arXiv:0809.1037.Bibcode:2008AJ....136.1901L.doi:10.1088/0004-6256/136/5/1901.S2CID119242543.
  29. ^Mayor, M.; Udry, S.; Naef, D.; Pepe, F.; Queloz, D.; Santos, N. C.; Burnet, M. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE".Astronomy and Astrophysics.415(1): 391–402.arXiv:astro-ph/0310316.Bibcode:2004A&A...415..391M.doi:10.1051/0004-6361:20034250.S2CID5233877.
  30. ^Haghighipour, Nader; Butler, R. Paul; Rivera, Eugenio J.; Henry, Gregory W.; Vogt, Steven S. (2012). "The Lick-Carnegie Survey: A new two-planet system around the star HD 207832".The Astrophysical Journal.756(1): 91.arXiv:1207.2806.Bibcode:2012ApJ...756...91H.doi:10.1088/0004-637X/756/1/91.S2CID1137984.
  31. ^Aharonian, F.; et al. (2007). "An Exceptional VHE Gamma-Ray Flare of PKS 2155-304".The Astrophysical Journal.664(2): L71–L78.arXiv:0706.0797.Bibcode:2007ApJ...664L..71A.doi:10.1086/520635.S2CID119319369.
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