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Delphinus

Coordinates:Sky map20h42m00s,+13° 48′ 00″
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This article is about the constellation. For other uses, seeDelphinus (disambiguation).
Delphinus
Constellation
Delphinus
List of stars in Delphinus
AbbreviationDel
GenitiveDelphini
Pronunciation/dɛlˈfaɪnəs/Delfínus,genitive/dɛlˈfaɪnaɪ/
Symbolismdolphin
Right ascension20h14m14.1594sto21h08m59.6073s[1]
Declination+2.4021468° to +20.9399471°[1]
QuadrantNQ4
Area189 sq. deg. (69th)
Main stars5
Bayer/Flamsteed
stars		19
Stars withplanets6
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)2
Brightest starRotanev(β Del) (3.63m)
Messier objects0
Meteor showersNone
Bordering
constellations		Vulpecula
Sagitta
Aquila
Aquarius
Equuleus
Pegasus
Visible at latitudes between +90° and −69°.
Best visible at 21:00 (9 p.m.) during the month ofSeptember.

Delphinus(Pronounced/dɛlˈfaɪnəs/or/ˈdɛlfɪnəs/) is a smallconstellationin theNorthern Celestial Hemisphere,close to thecelestial equator.Its name is theLatinversion for theGreekword fordolphin(δελφίς). It is one of the 48 constellations listed by the 2nd century astronomerPtolemy,and remains one of the 88 modern constellations recognized by theInternational Astronomical Union.It is one of the smaller constellations, ranked 69th in size. Delphinus' five brightest stars form a distinctiveasterismsymbolizing a dolphin with four stars representing the body and one the tail. It is bordered (clockwise from north) byVulpecula,Sagitta,Aquila,Aquarius,EquuleusandPegasus.

Delphinus is a faint constellation with only two stars brighter than anapparent magnitudeof 4,Beta Delphini(Rotanev) at magnitude 3.6 andAlpha Delphini(Sualocin) at magnitude 3.8.

Mythology

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Delphinus is depicted on the left of this card fromUrania's Mirror(1825)

Delphinus is associated with two stories fromGreek mythology.

According to myth, the first Greek godPoseidonwanted to marryAmphitrite,a beautifulnereid.However, wanting to protect her virginity, she fled to the Atlas mountains. Her suitor then sent out several searchers, among them a certain Delphinus. Delphinus accidentally stumbled upon her and was able to persuade Amphitrite to accept Poseidon's wooing. Out of gratitude the god placed the image of a dolphin among the stars.[2]

The second story tells of the Greek poetArionofLesbos(7th century BC), who was saved by a dolphin.[3]He was a court musician at the palace of Periander, ruler of Corinth. Arion had amassed a fortune during his travels to Sicily and Italy. On his way home fromTarentumhis wealth caused the crew of his ship to conspire against him. Threatened with death, Arion asked to be granted a last wish which the crew granted: he wanted to sing a dirge.[4]This he did, and while doing so, flung himself into the sea. There, he was rescued by a dolphin which had been charmed by Arion's music. The dolphin carried Arion to the coast of Greece and left.[5]

In non-Western astronomy

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InChinese astronomy,the stars of Delphinus are located withinthe Black Tortoise of the North( phương bắc Huyền Vũ,Běi Fāng Xuán Wǔ).[6]

InPolynesia,two cultures recognized Delphinus as a constellation. InPukapuka,it was calledTe Toloaand in theTuamotus,it was calledTe Uru-o-tiki.[7]

InHindu astrology,the Delphinus corresponds to theNakshatra,or lunar mansion, ofDhanishta.

Characteristics

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Delphinus is bordered byVulpeculato the north,Sagittato the northwest,Aquilato the west and southwest,Aquariusto the southeast,Equuleusto the east andPegasusto the east.[1]Covering 188.5 square degrees, corresponding to 0.457% of the sky, it ranks 69th of the 88 constellations in size.[8]The three-letter abbreviation for the constellation, as adopted by the IAU in 1922, is "Del".[9]The official constellation boundaries, as set byEugène Delportein 1930, are defined by a polygon of 14 segments. In theequatorial coordinate system,theright ascensioncoordinates of these borders lie between20h14m14.1594sand21h08m59.6073s,while thedeclinationcoordinates are between +2.4021468° and +20.9399471°.[1]The whole constellation is visible to observers north of latitude69°S.[8][a]

Features

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The constellation Delphinus as it can be seen by the naked eye
Contrast and color enhanced photograph of Delphinus

Stars

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See also:List of stars in Delphinus

Delphinus has two stars above fourth(apparent) magnitude;its brightest star is of magnitude 3.6. The mainasterismin Delphinus is Job's Coffin, nearly a 45°-apexlozengeor diamond of the four brightest stars: Alpha, Beta, Gamma, and Delta Delphini. Delphinus is in a rich Milky Way star field. Alpha and Beta Delphini have 19th century names Sualocin and Rotanev, read backwards: Nicolaus Venator, the Latinized name of aPalermo Observatorydirector,Niccolò Cacciatore(d. 1841).[3]

Alpha Delphiniis a blue-white huedmain sequencestar of magnitude 3.8,[10]241 light-years from Earth. It is a spectroscopic binary.[11]It is officially named Sualocin.[12][13]The star has an absolute magnitude of -0.4.[14]

Beta Delphiniis officially called Rotanev.[12]It was found to be a binary star in 1873.[15]The gap between its closebinarystars is visible from large amateur telescopes. To the unaided eye, it appears to be a white star of magnitude 3.6.[16][15]It has a period of 27 years and is 97 light-years from Earth.

Gamma Delphiniis a celebrated binary star among amateur astronomers. The primary is orange-gold of magnitude 4.3; the secondary is a light yellow star of magnitude 5.1. The pair form a true binary with an estimated orbital period of over 3,000 years. 125 light-years away, the two components are visible in a small amateur telescope.[3]The secondary, also described as green, is 10 arcseconds from the primary.Struve 2725,called the "Ghost Double", is a pair that appears similar but dimmer. Its components of magnitudes 7.6 and 8.4 are separated by 6 arcseconds and are 15 arcminutes from Gamma Delphini itself.[5]An unconfirmed exoplanet with a minimum mass of 0.7 Jupiter masses may orbit one of the stars.[17][18]

Delta Delphiniis a typeA-type star[19]of magnitude 4.43.[20]It is a spectroscopic binary, and both stars areDelta Scuti variables.[21]

Epsilon Delphini,Deneb Dulfim (lit."tail [of the] Dolphin" ), or Aldulfin, is a star ofstellar classB6 III.[22]Its magnitude is variable at around 4.03.[23][24]

Zeta Delphini,an A3Va[25]main-sequence star of magnitude 4.6, was in 2014 discovered to have abrown dwarforbiting around it. Zeta Delphini B has a mass of 50±15MJ.[25]

Animation fading-in ofAquila,Delphinus,Sagitta,and the summerMilky Wayas seen inDark-sky preserve Westhavelland

Rho Aquilaeat magnitude 4.94[26]is at about 150 light-years away.[26]Due to itsproper motionit has been in the (round-figure parameter) bounds of the constellation since 1992.[27]It is anA-type main sequence starwith a lower metallicity than the Sun.[28]

HR Delphiniwas anovathat brightened to magnitude 3.5 in December 1967.[29]It took an unusually long time for the nova to reach peak brightness which indicate that it barely satisfied the conditions for a thermonuclear runaway.[30]Another nova by the nameV339 Delphiniwas detected in 2013; it peaked at magnitude 4.3 and was the first nova observed to produce lithium.[31][32][33][34]

Musica,also known by its Flamsteed designation 18 Delphini, is one of the five stars with known planets located in Delphinus. It has a spectral type of G6 III.[35]Arion,the planet, is a very dense and massive planet with a mass at least 10.3 times greater than Jupiter.[36]Arion was part of the firstNameExoWorldscontest where the public got the opportunity to suggest names for exoplanets and their host stars.[37]

Exoplanets

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In 2024 the planet TOI-6883 b was discovered in the constellation Delphinus.[38]It has a 16.249 day orbital period around its host star,[39]a radius 1.08 times Jupiter's,[40]and a mass 4.34 times Jupiter's.[39]It was discovered from a single transit[40]in TESS data and it was confirmed by a network of citizen scientists.[39]

Deep-sky objects

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Its richMilky Waystar field means many modestly deep-sky objects.NGC 6891is aplanetary nebulaof magnitude 10.5; another isNGC 6905or the Blue Flash Nebula. The Blue Flash Nebula shows broad emission lines. The central star in NGC 6905 has a spectral of WO2, meaning it is rich in oxygen.[41]

NGC 6934is aglobular clusterof magnitude 9.75. It is about 52,000 light-years away from the Solar System.[42]It is in theShapley-Sawyer Concentration ClassVIII[43]and is thought to share a common origin with another globular cluster inBoötes.[44]It has an intermediate metallicity for a globular cluster,[45]but as of 2018 it has been poorly studied.[46]At a distance of about 137,000 light-years,[44]the globular clusterNGC 7006is at the outer reaches of the galaxy. It is also fairly dim at magnitude 11.5 and is in Class I.[43]

See also

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Notes

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  1. ^While parts of the constellation rise above the horizon to observers between 69°S and87°S,stars within a few degrees of the horizon are practically unobservable.[8]

Citations

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  1. ^abcd"Delphinus, Constellation Boundary".The Constellations.International Astronomical Union.Retrieved15 July2020.
  2. ^Pseudo-Hyginus."HYGINUS, ASTRONOMICA 2.1-17".Theoi Classical Texts Library.RetrievedJune 26,2017.
  3. ^abcRidpath & Tirion 2017,pp. 140–141.
  4. ^Herodotus,HistoriesI.23-24;
    alsoAulus Gellius,Noctes AtticaeXVI.19;Plutarch,Conv. sept. sap.160–62;Shakespeare,Twelfth Night(Act I, Sc 2, line 16)
  5. ^abSchaaf, Fred (September 2012). "The Celestial Dolphin".Sky and Telescope.124(3): 47.Bibcode:2012S&T...124c..47S.
  6. ^(in Chinese)AEEA (Activities of Exhibition and Education in Astronomy) thiên văn giáo dục tin tức võng 2006 năm 7 nguyệt 4 ngày
  7. ^Makemson 1941,p. 283.
  8. ^abcRidpath, Ian."Constellations: Andromeda–Indus".Star Tales.Self-published.Retrieved4 March2016.
  9. ^Russell, Henry Norris(1922). "The New International Symbols for the Constellations".Popular Astronomy.30:469.Bibcode:1922PA.....30..469R.
  10. ^Oja, T. (1991). "UBV photometry of stars whose positions are accurately known. VI".Astronomy and Astrophysics Supplement Series.89:415.Bibcode:1991A&AS...89..415O.
  11. ^Malkov, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012)."Dynamical masses of a selected sample of orbital binaries".Astronomy & Astrophysics.546:A69.Bibcode:2012A&A...546A..69M.doi:10.1051/0004-6361/201219774.
  12. ^abKunitzsch, Paul; Smart, Tim (2006).A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations(2nd rev. ed.). Cambridge, Massachusetts: Sky Pub.ISBN978-1-931559-44-7.
  13. ^"Naming Stars".IAU.org.Retrieved16 December2017.
  14. ^Jaschek, C.; Gomez, A. E. (1998). "The absolute magnitude of the early type MK standards from HIPPARCOS parallaxes".Astronomy and Astrophysics.330:619.Bibcode:1998A&A...330..619J.
  15. ^abBurnham, Robert (1978),Burnham's celestial handbook: an observer's guide to the universe beyond the Solar System,Dover Books on Astronomy, vol. 2 (2nd ed.),Courier Dover Publications,p. 820,ISBN0-486-23568-8
  16. ^Davidson, James W. Jr.; et al. (November 2009), "A Photometric Analysis of Seventeen Binary Stars Using Speckle Imaging",The Astronomical Journal,138(5): 1354–1364,Bibcode:2009AJ....138.1354D,doi:10.1088/0004-6256/138/5/1354,S2CID122194357
  17. ^Irwin, A. W.; et al. (1999), Hearnshaw, J. B.; Scarfe, C. D. (eds.), "A Program for the Analysis of Long-Period Binaries: The Case of γ Delphini",Precise Stellar Radial Velocities. IAU Colloquium 170,ASP Conference Series #185, vol. 185, p. 297,Bibcode:1999ASPC..185..297I,ISBN1-58381-011-0
  18. ^Wittemeyer; et al. (2006). "Detection Limits from the McDonald Observatory Planet Search Program".The Astronomical Journal.132(1): 177–188.arXiv:astro-ph/0604171.Bibcode:2006AJ....132..177W.doi:10.1086/504942.S2CID16755455.
  19. ^Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars",The Astronomical Journal,121(4): 2148–2158,Bibcode:2001AJ....121.2148G,doi:10.1086/319956.
  20. ^Chang, S.-W.; et al. (2013), "Statistical Properties of Galactic δ Scuti Stars: Revisited",The Astronomical Journal,145(5): 132,arXiv:1303.1031,Bibcode:2013AJ....145..132C,doi:10.1088/0004-6256/145/5/132,S2CID118900730.
  21. ^Liakos, Alexios; Niarchos, Panagiotis (February 2017), "Catalogue and properties of δ Scuti stars in binaries",Monthly Notices of the Royal Astronomical Society,465(1): 1181–1200,arXiv:1611.00200,Bibcode:2017MNRAS.465.1181L,doi:10.1093/mnras/stw2756.
  22. ^Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?",Astrophysical Journal Supplement,17:371,Bibcode:1968ApJS...17..371L,doi:10.1086/190179.
  23. ^Samus, N. N.; et al. (January 2017), "General Catalogue of Variable Stars",Astronomy Reports,GCVS 5.1,61(1): 80–88,Bibcode:2017ARep...61...80S,doi:10.1134/S1063772917010085,S2CID125853869.
  24. ^Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere",The Astronomical Journal,76:1058,Bibcode:1971AJ.....76.1058C,doi:10.1086/111220.
  25. ^abDe Rosa, R. J.; Patience, J.; Ward-Duong, K.; Vigan, A.; Marois, C.; Song, I.; Macintosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; Lai, O.; McCarthy, D. W.; Kulesa, C. (December 2014)."The VAST Survey - IV. A wide brown dwarf companion to the A3V star ζ Delphini".Monthly Notices of the Royal Astronomical Society.445(4): 3694.arXiv:1410.0005.Bibcode:2014MNRAS.445.3694D.doi:10.1093/mnras/stu2018.ISSN0035-8711.
  26. ^abWielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions",Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg,35(35), Astronomisches Rechen-Institut Heidelberg: 1,Bibcode:1999VeARI..35....1W.
  27. ^Patrick Moore (29 June 2013).The Observer's Year: 366 Nights of the Universe.Springer Science & Business Media. pp. 132–.ISBN978-1-4471-3613-2.
  28. ^Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevic, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; de Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (1 August 2019), "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18",Astronomy and Astrophysics,628:A94,arXiv:1904.11302,Bibcode:2019A&A...628A..94A,doi:10.1051/0004-6361/201935765,ISSN0004-6361,S2CID131780028.
  29. ^Isles, J. E. (1974). "HR Delphini (Nova 1967) in 1967 - 71".Journal of the British Astronomical Association.85:54–58.Bibcode:1974JBAA...85...54I.
  30. ^Friedjung, M (17 March 1992)."The unusual nature of nova HR Delphini 1967".Astronomy & Astrophysics.262(262): 487.Bibcode:1992A&A...262..487F.Retrieved19 July2020.
  31. ^Tajitsu, Akito; Sadakane, Kozo; Naito, Hiroyuki; Arai, Akira; Aoki, Wako (18 February 2015). "Explosive lithium production in the classical nova V339 Del (Nova Delphini 2013)".Nature.518(7539): 381–384.arXiv:1502.05598.Bibcode:2015Natur.518..381T.doi:10.1038/nature14161.PMID25693569.S2CID205242345.
  32. ^King, Bob (August 14, 2013)."Bright New Nova In Delphinus — You can See it Tonight With Binoculars".Universe Today (initial designation PNV J20233073+2046041).RetrievedAugust 15,2013.
  33. ^Guido, Ernesto; Ruocco, Nello; Howes, Nick (August 15, 2013)."Possible Bright Nova in Delphinus".Associazione Friulana di Astronomia e Meteorologia.RetrievedAugust 15,2013.
  34. ^Masi, Gianluca (August 15, 2013)."Nova Delphini 2013 (formerly PNV J20233073+2046041): images, spectra and maps".Gianluca Masi-Virtual Telescope Project.RetrievedAugust 15,2013.
  35. ^Opolski, A. (1957). "The spectrophotometric parallaxes of 42 visual binaries".Arkiv för Astronomi.2:55.Bibcode:1957ArA.....2...55O.
  36. ^Sato, Bun’ei; Izumiura, Hideyuki; Toyota, Eri; Kambe, Eiji; Ikoma, Masahiro; Omiya, Masashi; Masuda, Seiji; Takeda, Yoichi; Murata, Daisuke; Itoh, Yoichi; Ando, Hiroyasu; Yoshida, Michitoshi; Kokubo, Eiichiro; Ida, Shigeru (25 June 2008)."Planetary Companions around Three Intermediate-Mass G and K Giants: 18 Delphini, ξ Aquilae, and HD 81688".Publications of the Astronomical Society of Japan.60(3): 539–550.arXiv:0802.2590.Bibcode:2008PASJ...60..539S.doi:10.1093/pasj/60.3.539.ISSN0004-6264.
  37. ^"International Astronomical Union | IAU".iau.org.Retrieved19 July2020.
  38. ^Martin, Pierre-Yves (2024)."Planet TOI-6883 b".exoplanet.eu.Retrieved2024-05-30.
  39. ^abcSgro, Lauren A.; Dalba, Paul A.; Esposito, Thomas M.; Marchis, Franck; Dragomir, Diana; Villanueva Jr., Steven; Fulton, Benjamin; Billiani, Mario; Loose, Margaret (2024-05-23)."Confirmation and Characterization of the Eccentric, Warm Jupiter TIC 393818343 b with a Network of Citizen Scientists".The Astronomical Journal.168(1): 26.arXiv:2405.15021.Bibcode:2024AJ....168...26S.doi:10.3847/1538-3881/ad5096.
  40. ^abConzo, G.; Moriconi, M. (2024-02-26)."TOI-6883.01: A Single-transit Planet Candidate Detected from TESS".Research Notes of the AAS.8(2): 53.Bibcode:2024RNAAS...8...53C.doi:10.3847/2515-5172/ad2c85.ISSN2515-5172.
  41. ^Gómez-González, V M A.; Rubio, G.; Toalá, J. A.; Guerrero, M. A.; Sabin, L.; Todt, H.; Gómez-Llanos, V.; Ramos-Larios, G.; Mayya, Y. D. (2022)."Planetary nebulae with Wolf–Rayet-type central stars – III. A detailed view of NGC 6905 and its central star".Monthly Notices of the Royal Astronomical Society.509:974–989.arXiv:2110.09551.doi:10.1093/mnras/stab3042.
  42. ^Dinescu, Dana I.; et al. (October 2001). "Orbits of Globular Clusters in the Outer Galaxy: NGC 7006".The Astronomical Journal.122(4): 1916–1927.arXiv:astro-ph/0106259.Bibcode:2001AJ....122.1916D.doi:10.1086/323094.S2CID1232455.
  43. ^abShapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters",Harvard College Observatory Bulletin,849(849): 11–14,Bibcode:1927BHarO.849...11S.
  44. ^abHessels, J. W. T.; et al. (November 2007), "A 1.4 GHz Arecibo Survey for Pulsars in Globular Clusters",The Astrophysical Journal,670(1): 363–378,arXiv:0707.1602,Bibcode:2007ApJ...670..363H,doi:10.1086/521780,S2CID16914232.
  45. ^Kaluzny, J.; et al. (March 2001). "Image-Subtraction Photometry of Variable Stars in the Field of the Globular Cluster NGC 6934".The Astronomical Journal.121(3): 1533–1550.arXiv:astro-ph/0010303.Bibcode:2001AJ....121.1533K.doi:10.1086/319411.S2CID14431121.
  46. ^Marino, A. F.; et al. (June 2018)."Metallicity Variations in the Type II Globular Cluster NGC 6934".The Astrophysical Journal.859(2): 20.arXiv:1804.04158.Bibcode:2018ApJ...859...81M.doi:10.3847/1538-4357/aabdea.S2CID119461759.81.

References

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