Astronomy:Epsilon Canis Minoris

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Short description: Suspected binary star system in the constellation Canis Minor
ε Canis Minoris
Canis Minor constellation map.svg
Red circle.svg
Location of ε Canis Minoris (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Canis Minor
Right ascension  07h 25m 38.89613s[1]
Declination +09° 16′ 33.9541″[1]
Apparent magnitude (V) +5.002[2]
Characteristics
Spectral type G6.5 IIb[3]
U−B color index +0.774[2]
B−V color index +1.004[2]
Astrometry
Radial velocity (Rv)−7.8±1.3[4] km/s
Proper motion (μ) RA: −3.338 ± 0.385[5] mas/yr
Dec.: −8.497 ± 0.310[5] mas/yr
Parallax (π)4.2624 ± 0.2288[5] mas
Distance770 ± 40 ly
(230 ± 10 pc)
Absolute magnitude (MV)−2.62[6]
Details[7]
Mass4.63±0.17 M☉
Radius45.51±4.34 R☉
Luminosity1,086.5±197.8 L☉
Surface gravity (log g)1.81±0.06 cgs
Temperature4,916±70 K
Metallicity [Fe/H]−0.12±0.10 dex
Rotational velocity (v sin i)8[8] km/s
Age140±10 Myr
Other designations
ε CMi, 2 CMi, BD+09°1643, GC 9908, HD 58367, HIP 36041, HR 2828, SAO 115425[9]
Database references
SIMBADdata

Epsilon Canis Minoris (ε Canis Minoris) is a suspected binary star[10] system in the equatorial constellation of Canis Minor. It is a fifth magnitude star, which means it is bright enough to be faintly visible to the naked eye.[2] Based upon an annual parallax shift of just 3.13 mas as seen from Earth,[1] this star is located roughly 770 light years from the Sun, give or take a 40 light year margin of error.[5]

This is an evolved G-type bright giant star with a stellar classification of G6.5 IIb.[3] It is most likely (99% chance) on the horizontal branch,[7] and is a barium star that shows an abnormal overabundance of barium in its spectrum.[11] This s-process element may have been accreted from a now white dwarf companion during a previous stage of its evolution.[10] The bright giant component has an estimated 4.63 times the mass of the Sun and has expanded to 45.5 times the Sun's radius. The star is radiating 1,087 times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 4,916 K.[7]

References

  1. ↑ 1.0 1.1 1.2 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society 172 (3): 667–679, doi:10.1093/mnras/172.3.667, Bibcode: 1975MNRAS.172..667J. 
  3. ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K. 
  4. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D. 
  5. ↑ 5.0 5.1 5.2 5.3 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  6. ↑ Takeda, Yoichi et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan 60 (4): 781–802, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T. 
  7. ↑ 7.0 7.1 7.2 Reffert, Sabine et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics 574A (2): 116–129, doi:10.1051/0004-6361/201322360, Bibcode: 2015A&A...574A.116R.  Values are based on 99% probability it is on the horizontal branch.
  8. ↑ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago 239 (1): 1, Bibcode: 1970CoAsi.239....1B. 
  9. ↑ "eps CMi". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eps+CMi. 
  10. ↑ 10.0 10.1 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, Bibcode: 2008MNRAS.389..869E. 
  11. ↑ Williams, P. M. (February 1975), "Stellar compositions from narrow-band photometry - V. Barium abundances for 200 evolved stars", Monthly Notices of the Royal Astronomical Society 170 (2): 343–362, doi:10.1093/mnras/170.2.343, Bibcode: 1975MNRAS.170..343W. 



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