Astronomy:Eta Canis Minoris

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Short description: Binary star system in the constellation Canis Minor

Template:Starbox observe 1s Template:Starbox observe 1s

η Canis Minoris
Location of η Canis Minoris (circled)
Characteristics
Spectral type F0 III[1]
U−B color index +0.17[2]
B−V color index +0.22[2]
Astrometry
A
Radial velocity (Rv)+17.2[3] km/s
Proper motion (μ) RA: −3.109[4] mas/yr
Dec.: −43.633[4] mas/yr
Parallax (π)10.2172 ± 0.1069[4] mas
Distance319 ± 3 ly
(98 ± 1 pc)
Absolute magnitude (MV)0.1[5]
B
Proper motion (μ) RA: −1.915 mas/yr
Dec.: −44.581 mas/yr
Parallax (π)10.2562 ± 0.0271[6] mas
Distance318.0 ± 0.8 ly
(97.5 ± 0.3 pc)
Details
η CMi A
Mass2.16[3] M☉
Radius3.6[lower-alpha 1] R☉
Luminosity57.5[3] L☉
Surface gravity (log g)3.66[7] cgs
Temperature7,505±66[3] K
Rotational velocity (v sin i)54[8] km/s
Age818[7] Myr
Other designations
η CMi, 5 CMi, BD+07°1729, GC 9970, HD 58923, HIP 36265, HR 2851, SAO 115477, ADS 6101, CCDM 07280+0657, WDS J07280+0657A[9]
Database references
SIMBADdata
B

Eta Canis Minoris is a binary star[1] system in the equatorial constellation of Canis Minor. Its name is a Bayer designation that is Latinized from η Canis Minoris, and abbreviated Eta CMi or η CMi. The brighter component has an apparent visual magnitude of 5.25,[2] which indicates it is faintly visible to the naked eye. Based on parallax measurements,[4] the distance to this system is approximately 318 light-years (97 pc) from the Sun. It is drifting further away with a line of sight velocity of +17 km/s.[3]

The primary component, η Canis Minoris A, is a yellow-white F-type giant with a stellar classification of F0 III.[1] At the estimated age of 818 million years,[7] it shows a high rate of spin with a projected rotational velocity of 54 km/s.[8] The star has 2.2 times the mass of the Sun mass and is radiating 57.5[3] times the Sun's luminosity from its photosphere at an effective temperature of 7,505 K.[3]

The companion star was first reported by S. W. Burnham in 1872.[10] Designated η Canis Minoris B, it is an eleventh-magnitude star located at an angular separation of 4 arcseconds from the primary. At the distance of this system, this is equivalent to a physical separation of around 440 astronomical unit|AU from the main star, taking around 5,000 years to orbit it.[11]

Notes

  1. ↑ derived from known mass and surface gravity of star

References

  1. ↑ 1.0 1.1 1.2 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. 
  2. ↑ 2.0 2.1 2.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal 150 (3): 23, doi:10.1088/0004-6256/150/3/88, 88, Bibcode: 2015AJ....150...88L. 
  4. ↑ 4.0 4.1 4.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940.  Gaia DR3 record for this source at VizieR.
  5. ↑ Jaschek, C.; Gomez, A. E. (1998), "The absolute magnitude of the early type MK standards from HIPPARCOS parallaxes", Astronomy and Astrophysics 330 (619–625): 619, Bibcode: 1998A&A...330..619J. 
  6. ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940.  Gaia DR3 record for this source at VizieR.
  7. ↑ 7.0 7.1 7.2 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal 804 (2): 146, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D. 
  8. ↑ 8.0 8.1 Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, doi:10.1051/0004-6361:20020943, Bibcode: 2002A&A...393..897R. 
  9. ↑ "eta CMi". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eta+CMi. 
  10. ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M. 
  11. ↑ Kaler, Jim, "Eta and Delta-1 CMi", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/etacmi.html, retrieved 2017-09-01. 



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