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Alpha Fornacis

October 21, 2023

Alpha Fornacis (α Fornacis, abbreviated Alpha For, α For) is a binary star[12] system in the southern constellation of Fornax. It is the brightest star in the constellation and the only one brighter than magnitude 4.0. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 46 light-years (14 parsecs) distant from the Sun.

Alpha Fornacis

Location of α Fornacis (upper left).
Observation data
Epoch J2000      Equinox J2000
Constellation Fornax
Right ascension 3h 12m 04.5277s[1]
Declination –28° 59′ 15.425″[1]
Apparent magnitude (V) 3.85[2] (3.98/7.19)[3]
Characteristics
Spectral type F8IV[4]
U−B color index +0.082[5]
B−V color index +0.581[5]
Astrometry
Radial velocity (Rv)–20.5[6] km/s
Proper motion (μ) RA: 371.49[1] mas/yr
Dec.: 612.28[1] mas/yr
Parallax (π)71.4337 ± 0.1320 mas[7]
Distance45.66 ± 0.08 ly
(14.00 ± 0.03 pc)
Absolute magnitude (MV)3.08[8]
Orbit[3]
Period (P)269 yr
Semi-major axis (a)4.0″
Eccentricity (e)0.73
Inclination (i)81°
Longitude of the node (Ω)117°
Periastron epoch (T)1947
Argument of periastron (ω)
(secondary)		43°
Details
α For A
Mass1.33 ± 0.01[9] M☉
Radius2.04 ± 0.06[10] R☉
Luminosity4.87 ± 0.16[10] L☉
Surface gravity (log g)4.27[9] cgs
Temperature6,240[9] K
Metallicity [Fe/H]–0.20[9] dex
Rotational velocity (v sin i)3.9[10] km/s
Age2.9[11] Gyr
Other designations
α For, 12 Eridani, CD−29° 1177, GJ 127, HD 20010, HIP 14879, HR 963, SAO 168373, LTT 1512, 2MASS J03120443-2859156[2]
Database references
SIMBADdata

Its two components are designated Alpha Fornacis A (officially named Dalim /ˈdeɪlɪm/)[13] and B.

Nomenclature Edit

α Fornacis (Latinised to Alpha Fornacis) is the system's Bayer designation. The designations of the two components as Alpha Fornacis A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[14] Formerly it was designated as the 12th of Eridanus (12 Eri) by Flamsteed.[15]

Indigenous Arabs had named both Alpha Eridani and Fomalhaut ظَلِيم al-ẓalīm, a local word for 'ostrich'. Later, Arabian astronomer would transfer the appellation to Theta Eridani, as they could not see those other stars from their location.[16] In recent times, Italian astronomer Giuseppe Piazzi applied it with the spelling Dalim to his "III 13" (= α For) in his Palermo Catalogue,[17][18][19] and Elijah Burritt labeled it Fornacis in his Atlas.[20]

In 2016, the IAU organized a Working Group on Star Names (WGSN)[21] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[22] It approved the name Dalim for the component Alpha Fornacis A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[13]

Properties Edit

Alpha Fornacis has a high proper motion[2] and the system displays an excess of infrared emission, which may indicate the presence of circumstellar material such as a debris disk.[23] The space velocity components of this star are (U, V, W) = (−35, +20, +30) km/s.[24] Approximately 350,000 years ago, Alpha Fornacis experienced a close encounter with the A-type main-sequence star Nu Horologii. The two came within an estimated 0.265 ly (0.081 pc) of each other, and both stars have debris disks.[25]

Alpha Fornacis A has a stellar classification of F8IV, where the luminosity class IV indicates this is a subgiant star that has just evolved off the main sequence.[26] It has 33% more mass than the Sun and is an estimated 2.9 billion years old.[9][11]

The secondary, Alpha Fornacis B, has been identified as a blue straggler, and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays and is 78% as massive as the Sun.[27]

References Edit

  1. ^ a b c d Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
  2. ^ a b c "LHS 1515 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-05-10.
  3. ^ a b Hartkopf, W. I.; et al. (June 30, 2006), , United States Naval Observatory, archived from the original on 2017-08-01, retrieved 2017-06-02.
  4. ^ Favata, F.; Micela, G.; Sciortino, S. (July 1997). "The [Fe/H] distribution of a volume limited sample of solar-type stars and its implications for galactic chemical evolution". Astronomy and Astrophysics. 323: 809–818. Bibcode:1997A&A...323..809F.
  5. ^ a b Rakos, K. D.; et al. (February 1982). "Photometric and astrometric observations of close visual binaries". Astronomy and Astrophysics Supplement Series. 47: 221–235. Bibcode:1982A&AS...47..221R.
  6. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.
  7. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  8. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  9. ^ a b c d e Santos, N. C.; Israelian, G.; Mayor, M. (July 2001). "The metal-rich nature of stars with planets". Astronomy and Astrophysics. 373 (3): 1019–1031. arXiv:astro-ph/0105216. Bibcode:2001A&A...373.1019S. doi:10.1051/0004-6361:20010648. S2CID 119347084.
  10. ^ a b c Bruntt, H.; et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society, 405 (3): 1907–1923, arXiv:1002.4268, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x, S2CID 118495267
  11. ^ a b Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S.; Mowlavi, N. (May 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs". Astronomy and Astrophysics. 418 (3): 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. S2CID 11027621. See VizierR catalogue V/130.
  12. ^ Söderhjelm, Staffan (January 1999). "Visual binary orbits and masses POST HIPPARCOS". Astronomy and Astrophysics. 341: 121–140. Bibcode:1999A&A...341..121S.
  13. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  14. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  15. ^ Wagman, 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. Bibcode:2003lslm.book.....W. ISBN 978-0-939923-78-6.
  16. ^ Kunitzsch, 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. pp. 36–37. ISBN 978-1-931559-44-7.
  17. ^ Piazzi, G, ed. (1814). Praecipuarum Stellarum Inerrantium Positiones Mediae Ineunte Saeculo XIX: ex Observationibus Habitis in Specula Panormitana ab anno 1792 ad annum 1813. Palermo. p. 21.
  18. ^ Kunitzsch, P. (1959). Arabische Sternnamen in Europa. Wiesbaden: Otto Harrassowitz. p. 155.
  19. ^ Laffitte, R. (2005). Héritages arabes: Des noms arabes pour les étoiles (2éme revue et corrigée ed.). Paris: Librairie Orientaliste Paul Geunthner / Les Cahiers de l'Orient. p. 229.
  20. ^ Burritt, E. H. (1835). Atlas, Designed to Illustrate the Geography of the Heavens (new ed.). New York: F. J. Huntington. plate III.
  21. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  22. ^ "WG Triennial Report (2015–2018) – Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  23. ^ Oudmaijer, Rene D.; et al. (December 1992). "SAO stars with infrared excess in the IRAS Point Source Catalog". Astronomy and Astrophysics Supplement Series. 96 (3): 625–643. Bibcode:1992A&AS...96..625O.
  24. ^ Gliese, W. (1969). "Catalogue of Nearby Stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. 22: 1. Bibcode:1969VeARI..22....1G.
  25. ^ Deltorn, J.-M.; Kalas, P. (2001). "Search for Nemesis Encounters with Vega, ε Eridani, and Fomalhaut". In Ray Jayawardhana; Thomas Greene (eds.). Young Stars Near Earth: Progress and Prospects. ASP Conference Series. Vol. 244. San Francisco: Astronomical Society of the Pacific. p. 227. arXiv:astro-ph/0105284. Bibcode:2001ASPC..244..227D. ISBN 1-58381-082-X.
  26. ^ Lopez, Bruno; Schneider, Jean; Danchi, William C. (July 2005). "Can Life Develop in the Expanded Habitable Zones around Red Giant Stars?". The Astrophysical Journal. 627 (2): 974–985. arXiv:astro-ph/0503520. Bibcode:2005ApJ...627..974L. doi:10.1086/430416. S2CID 17075384.
  27. ^ Fuhrmann, K.; Chini, R. (August 2015), "Multiplicity among F-type Stars. II", The Astrophysical Journal, 809 (1): 19, Bibcode:2015ApJ...809..107F, doi:10.1088/0004-637X/809/1/107, 107.

External links Edit

  • α For (Dalim) – SKY-MAP.ORG
  • LHL Digital Collections – Linda Hall library

October 21, 2023
alpha, fornacis, fornacis, abbreviated, alpha, binary, star, system, southern, constellation, fornax, brightest, star, constellation, only, brighter, than, magnitude, based, parallax, measurements, obtained, during, hipparcos, mission, approximately, light, ye. Alpha Fornacis a Fornacis abbreviated Alpha For a For is a binary star 12 system in the southern constellation of Fornax It is the brightest star in the constellation and the only one brighter than magnitude 4 0 Based on parallax measurements obtained during the Hipparcos mission it is approximately 46 light years 14 parsecs distant from the Sun Alpha FornacisLocation of a Fornacis upper left Observation dataEpoch J2000 Equinox J2000Constellation FornaxRight ascension 3h 12m 04 5277s 1 Declination 28 59 15 425 1 Apparent magnitude V 3 85 2 3 98 7 19 3 CharacteristicsSpectral type F8IV 4 U B color index 0 082 5 B V color index 0 581 5 AstrometryRadial velocity Rv 20 5 6 km sProper motion m RA 371 49 1 mas yr Dec 612 28 1 mas yrParallax p 71 4337 0 1320 mas 7 Distance45 66 0 08 ly 14 00 0 03 pc Absolute magnitude MV 3 08 8 Orbit 3 Period P 269 yrSemi major axis a 4 0 Eccentricity e 0 73Inclination i 81 Longitude of the node W 117 Periastron epoch T 1947Argument of periastron w secondary 43 Detailsa For AMass1 33 0 01 9 M Radius2 04 0 06 10 R Luminosity4 87 0 16 10 L Surface gravity log g 4 27 9 cgsTemperature6 240 9 KMetallicity Fe H 0 20 9 dexRotational velocity v sin i 3 9 10 km sAge2 9 11 GyrOther designationsa For 12 Eridani CD 29 1177 GJ 127 HD 20010 HIP 14879 HR 963 SAO 168373 LTT 1512 2MASS J03120443 2859156 2 Database referencesSIMBADdataIts two components are designated Alpha Fornacis A officially named Dalim ˈ d eɪ l ɪ m 13 and B Contents 1 Nomenclature 2 Properties 3 References 4 External linksNomenclature Edita Fornacis Latinised to Alpha Fornacis is the system s Bayer designation The designations of the two components as Alpha Fornacis A and B derive from the convention used by the Washington Multiplicity Catalog WMC for multiple star systems and adopted by the International Astronomical Union IAU 14 Formerly it was designated as the 12th of Eridanus 12 Eri by Flamsteed 15 Indigenous Arabs had named both Alpha Eridani and Fomalhaut ظ ل يم al ẓalim a local word for ostrich Later Arabian astronomer would transfer the appellation to Theta Eridani as they could not see those other stars from their location 16 In recent times Italian astronomer Giuseppe Piazzi applied it with the spelling Dalim to his III 13 a For in his Palermo Catalogue 17 18 19 and Elijah Burritt labeled it Fornacis in his Atlas 20 In 2016 the IAU organized a Working Group on Star Names WGSN 21 to catalog and standardize proper names for stars The WGSN decided to attribute proper names to individual stars rather than entire multiple systems 22 It approved the name Dalim for the component Alpha Fornacis A on 5 September 2017 and it is now so included in the List of IAU approved Star Names 13 Properties EditAlpha Fornacis has a high proper motion 2 and the system displays an excess of infrared emission which may indicate the presence of circumstellar material such as a debris disk 23 The space velocity components of this star are U V W 35 20 30 km s 24 Approximately 350 000 years ago Alpha Fornacis experienced a close encounter with the A type main sequence star Nu Horologii The two came within an estimated 0 265 ly 0 081 pc of each other and both stars have debris disks 25 Alpha Fornacis A has a stellar classification of F8IV where the luminosity class IV indicates this is a subgiant star that has just evolved off the main sequence 26 It has 33 more mass than the Sun and is an estimated 2 9 billion years old 9 11 The secondary Alpha Fornacis B has been identified as a blue straggler and has either accumulated material from or merged with a third star in the past It is a strong source of X rays and is 78 as massive as the Sun 27 References Edit a b c d Perryman M A C et al April 1997 The HIPPARCOS Catalogue Astronomy amp Astrophysics 323 L49 L52 Bibcode 1997A amp A 323L 49P a b c LHS 1515 High proper motion Star SIMBAD Centre de Donnees astronomiques de Strasbourg Retrieved 2010 05 10 a b Hartkopf W I et al June 30 2006 Sixth Catalog of Orbits of Visual Binary Stars United States Naval Observatory archived from the original on 2017 08 01 retrieved 2017 06 02 Favata F Micela G Sciortino S July 1997 The Fe H distribution of a volume limited sample of solar type stars and its implications for galactic chemical evolution Astronomy and Astrophysics 323 809 818 Bibcode 1997A amp A 323 809F a b Rakos K D et al February 1982 Photometric and astrometric observations of close visual binaries Astronomy and Astrophysics Supplement Series 47 221 235 Bibcode 1982A amp AS 47 221R Evans D S June 20 24 1966 The Revision of the General Catalogue of Radial Velocities In Batten Alan Henry Heard John Frederick eds Determination of Radial Velocities and their Applications Proceedings from IAU Symposium no 30 University of Toronto International Astronomical Union Bibcode 1967IAUS 30 57E Brown A G A et al Gaia collaboration 2021 Gaia Early Data Release 3 Summary of the contents and survey properties Astronomy amp Astrophysics 649 A1 arXiv 2012 01533 Bibcode 2021A amp A 649A 1G doi 10 1051 0004 6361 202039657 S2CID 227254300 Erratum doi 10 1051 0004 6361 202039657e Gaia EDR3 record for this source at VizieR Holmberg J et al July 2009 The Geneva Copenhagen survey of the solar neighbourhood III Improved distances ages and kinematics Astronomy and Astrophysics 501 3 941 947 arXiv 0811 3982 Bibcode 2009A amp A 501 941H doi 10 1051 0004 6361 200811191 S2CID 118577511 a b c d e Santos N C Israelian G Mayor M July 2001 The metal rich nature of stars with planets Astronomy and Astrophysics 373 3 1019 1031 arXiv astro ph 0105216 Bibcode 2001A amp A 373 1019S doi 10 1051 0004 6361 20010648 S2CID 119347084 a b c Bruntt H et al July 2010 Accurate fundamental parameters for 23 bright solar type stars Monthly Notices of the Royal Astronomical Society 405 3 1907 1923 arXiv 1002 4268 Bibcode 2010MNRAS 405 1907B doi 10 1111 j 1365 2966 2010 16575 x S2CID 118495267 a b Nordstrom B Mayor M Andersen J Holmberg J Pont F Jorgensen B R Olsen E H Udry S Mowlavi N May 2004 The Geneva Copenhagen survey of the Solar neighbourhood Ages metallicities and kinematic properties of 14 000 F and G dwarfs Astronomy and Astrophysics 418 3 989 1019 arXiv astro ph 0405198 Bibcode 2004A amp A 418 989N doi 10 1051 0004 6361 20035959 S2CID 11027621 See VizierR catalogue V 130 Soderhjelm Staffan January 1999 Visual binary orbits and masses POST HIPPARCOS Astronomy and Astrophysics 341 121 140 Bibcode 1999A amp A 341 121S a b Naming Stars IAU org Retrieved 16 December 2017 Hessman F V Dhillon V S Winget D E Schreiber M R Horne K Marsh T R Guenther E Schwope A Heber U 2010 On the naming convention used for multiple star systems and extrasolar planets arXiv 1012 0707 astro ph SR Wagman 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 amp Woodward Publishing Company Bibcode 2003lslm book W ISBN 978 0 939923 78 6 Kunitzsch 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 pp 36 37 ISBN 978 1 931559 44 7 Piazzi G ed 1814 Praecipuarum Stellarum Inerrantium Positiones Mediae Ineunte Saeculo XIX ex Observationibus Habitis in Specula Panormitana ab anno 1792 ad annum 1813 Palermo p 21 Kunitzsch P 1959 Arabische Sternnamen in Europa Wiesbaden Otto Harrassowitz p 155 Laffitte R 2005 Heritages arabes Des noms arabes pour les etoiles 2eme revue et corrigee ed Paris Librairie Orientaliste Paul Geunthner Les Cahiers de l Orient p 229 Burritt E H 1835 Atlas Designed to Illustrate the Geography of the Heavens new ed New York F J Huntington plate III IAU Working Group on Star Names WGSN Retrieved 22 May 2016 WG Triennial Report 2015 2018 Star Names PDF p 5 Retrieved 2018 07 14 Oudmaijer Rene D et al December 1992 SAO stars with infrared excess in the IRAS Point Source Catalog Astronomy and Astrophysics Supplement Series 96 3 625 643 Bibcode 1992A amp AS 96 625O Gliese W 1969 Catalogue of Nearby Stars Veroffentlichungen des Astronomischen Rechen Instituts Heidelberg 22 1 Bibcode 1969VeARI 22 1G Deltorn J M Kalas P 2001 Search for Nemesis Encounters with Vega e Eridani and Fomalhaut In Ray Jayawardhana Thomas Greene eds Young Stars Near Earth Progress and Prospects ASP Conference Series Vol 244 San Francisco Astronomical Society of the Pacific p 227 arXiv astro ph 0105284 Bibcode 2001ASPC 244 227D ISBN 1 58381 082 X Lopez Bruno Schneider Jean Danchi William C July 2005 Can Life Develop in the Expanded Habitable Zones around Red Giant Stars The Astrophysical Journal 627 2 974 985 arXiv astro ph 0503520 Bibcode 2005ApJ 627 974L doi 10 1086 430416 S2CID 17075384 Fuhrmann K Chini R August 2015 Multiplicity among F type Stars II The Astrophysical Journal 809 1 19 Bibcode 2015ApJ 809 107F doi 10 1088 0004 637X 809 1 107 107 External links Edita For Dalim SKY MAP ORG LHL Digital Collections Linda Hall library Retrieved from https en wikipedia org w index php title Alpha Fornacis amp oldid 1171238675, wikipedia, wiki, book, books, library,

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