Astronomy:Epsilon2 Arae

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Short description
Star in the constellation Ara
Epsilon2 Arae
Diagram showing star positions and boundaries of the Ara constellation and its surroundings
Cercle rouge 100%.svg
The location of ε2 Arae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ara
Right ascension  17h 03m 08.70964s[1]
Declination –53° 14′ 13.3020″[1]
Apparent magnitude (V) 5.29[2] (5.44/8.65)[3]
Characteristics
Spectral type F5 V Fe+0.5[4]
U−B color index +0.015[5]
B−V color index +0.48[2]
Astrometry
Radial velocity (Rv)+4.9[6] km/s
Proper motion (μ) RA: +0.15[1] mas/yr
Dec.: −165.20[1] mas/yr
Parallax (π)36.73 ± 0.63[1] mas
Distance89 ± 2 ly
(27.2 ± 0.5 pc)
Absolute magnitude (MV)3.27[7]
Details
Surface gravity (log g)4.29[7] cgs
Temperature6,577[7] K
Metallicity [Fe/H]+0.02[7] dex
Rotational velocity (v sin i)45.4[8] km/s
Age1.9[6] Gyr
Other designations
CPD−53° 8316, GJ 3985, HD 153580, HIP 83431, HR 6314, SAO 244388.[5]
Database references
SIMBADdata

Epsilon2 Arae2 Arae, ε2 Ara) is the Bayer designation for a double star in the southern constellation of Ara. It is approximately 89 light-years (27 parsecs) distant from Earth. With an apparent visual magnitude of 5.3,[2] it is faintly visible to the naked eye.

The brighter star is a magnitude 5.44 F-type main sequence star with a stellar classification of F5 V Fe+0.5.[4] The Fe+0.5 notation indicates that it has a somewhat higher than normal abundance of iron. It has a magnitude 8.65 companion at an angular separation of 0.590 arcseconds.[3] It has a common proper motion white dwarf companion, WDS J17031-5314, with a magnitude of 13.47.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa 27: 11, Bibcode1968MNSSA..27...11C. 
  3. 3.0 3.1 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  4. 4.0 4.1 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode2006AJ....132..161G. 
  5. 5.0 5.1 "* eps02 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+eps02+Ara. 
  6. 6.0 6.1 Holmberg, J.; Nordström, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics Supplement Series 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode2009A&A...501..941H. 
  7. 7.0 7.1 7.2 7.3 Balachandran, Suchitra (May 1, 1990), "Lithium depletion and rotation in main-sequence stars", Astrophysical Journal, Part 1 354: 310–332, doi:10.1086/168691, Bibcode1990ApJ...354..310B. 
  8. Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2. 
  9. "GJ 2125 -- White Dwarf", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=GJ+2125, retrieved 2010-07-28. 

External links