Alpha Fornacis

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Alpha Fornacis
Fornax constellation map.png
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]
Characteristics
Spectral type F8IV[3]
U−B color index +0.082[4]
B−V color index +0.581[4]
Astrometry
Radial velocity (Rv) –20.5[5] km/s
Proper motion (μ) RA: 371.49[1] mas/yr
Dec.: 612.28[1] mas/yr
Parallax (π) 70.24 ± 0.45[1] mas
Distance 46.4 ± 0.3 ly
(14.24 ± 0.09 pc)
Absolute magnitude (MV) 3.08[6]
Details
Mass 1.33 ± 0.01[7] M
Radius 2.04 ± 0.06[8] R
Luminosity 4.87 ± 0.16[8] L
Surface gravity (log g) 4.27[7] cgs
Temperature 6,240[7] K
Metallicity [Fe/H] –0.20[7] dex
Rotational velocity (v sin i) 3.9[8] km/s
Age 2.9[9] Gyr
Other designations
12 Eridani, CD-29 1177, Gl 127, HD 20010, HIP 14879, HR 963, LTT 1512, SAO 168373.[2]
Database references
SIMBAD data

Alpha Fornacis (α Fornacis, α For) is the brightest star in the constellation Fornax. It is the only star brighter than magnitude 4.0 in the constellation. It has the proper names Dalim (in Piazzi's Palermo Catalogue)[10][11][12] and Fornacis (in Burritt's Atlas).[13] This star was originally designated 12 Eridani.

The stellar classification of Alpha Fornacis is F8IV, where the luminosity class IV indicates this is a subgiant star that has just evolved off the main sequence.[14] It has 33% more mass than the Sun and is an estimated 2.9 billion years old.[7][9] Alpha Fornacis is a binary star[15] and has a high proper motion.[2] This system displays an excess of infrared emission, which may indicate the presence of circumstellar material such as a debris disk.[16]

The secondary 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.[17]

The space velocity components of this star are (U, V, W) = (–35, +20, +30) km/s.[18] 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.[19]

References[edit]

  1. ^ a b c d e 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. ^ 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. 
  4. ^ 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. 
  5. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E. Retrieved 2009-09-10. 
  6. ^ 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, Bibcode:2009A&A...501..941H, arXiv:0811.3982Freely accessible, doi:10.1051/0004-6361/200811191. 
  7. ^ 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. Bibcode:2001A&A...373.1019S. arXiv:astro-ph/0105216Freely accessible. doi:10.1051/0004-6361:20010648. 
  8. ^ 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, Bibcode:2010MNRAS.405.1907B, arXiv:1002.4268Freely accessible, doi:10.1111/j.1365-2966.2010.16575.x 
  9. ^ 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. Bibcode:2004A&A...418..989N. arXiv:astro-ph/0405198Freely accessible. doi:10.1051/0004-6361:20035959.  See VizierR catalogue V/130.
  10. ^ 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. 
  11. ^ Kunitzsch, P. (1959). Arabische Sternnamen in Europa. Wiesbaden: Otto Harrassowitz. p. 155. 
  12. ^ 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. 
  13. ^ Burritt, E. H. (1835). Atlas, Designed to Illustrate the Geography of the Heavens (new ed.). New York: F. J. Huntington.  plate III.
  14. ^ 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. Bibcode:2005ApJ...627..974L. arXiv:astro-ph/0503520Freely accessible. doi:10.1086/430416. 
  15. ^ Söderhjelm, Staffan (January 1999). "Visual binary orbits and masses POST HIPPARCOS". Astronomy and Astrophysics. 341: 121–140. Bibcode:1999A&A...341..121S. 
  16. ^ 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. 
  17. ^ 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. 
  18. ^ Gliese, W. (1969). "Catalogue of Nearby Stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. Bibcode:1969VeARI..22....1G. 
  19. ^ Deltorn, J.-M.; Kalas, P. (2001). "Search for Nemesis Encounters with Vega, ε Eridani, and Fomalhaut". In Ray Jayawardhana; Thomas Greene. Young Stars Near Earth: Progress and Prospects. ASP Conference Series. 244. San Francisco: Astronomical Society of the Pacific. p. 227. Bibcode:2001ASPC..244..227D. ISBN 1-58381-082-X. 

External links[edit]