Gamma Canis Minoris

Gamma Canis Minoris (γ Canis Minoris) is a binary star system in the equatorial constellation Canis Minor. Its orange colour is obvious when seen through binoculars.[7] The system is visible to the naked eye with a combined apparent visual magnitude of +4.33.[2] Based upon an annual parallax shift of 10.25 mas as seen from Earth,[1] this system is located about 320 light years from the Sun.

γ Canis Minoris

Location of γ Canis Minoris (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Canis Minor
Right ascension	07^h 28^m 09.79333^s[1]
Declination	+08° 55′ 31.9068″[1]
Apparent magnitude (V)	+4.33[2] (4.46 + 6.66)[2]
Characteristics
Spectral type	K3 III Fe-0.5[3] (K4 III + K1: III)[2]
U−B color index	+1.53[4]
B−V color index	+1.43[4]
Astrometry
Radial velocity (Rv)	46.8±0.3[5] km/s
Proper motion (μ)	RA: −61.09[1] mas/yr Dec.: −10.70[1] mas/yr
Parallax (π)	10.25 ± 0.47[1] mas
Distance	320 ± 10 ly (98 ± 4 pc)
Absolute magnitude (MV)	−0.5±0.1[2]
Absolute magnitude (MV)	1.7±0.2[2]
Orbit[2]
Period (P)	389.310 ± 0.012d
Semi-major axis (a)	17 mas
Eccentricity (e)	0.25856 ± 0.00039
Inclination (i)	66°
Periastron epoch (T)	2449849.172 ± 0.089 HJD
Argument of periastron (ω) (secondary)	142.079 ± 0.090°
Semi-amplitude (K1) (primary)	21.243 ± 0.010 km/s
Semi-amplitude (K2) (secondary)	21.526 ± 0.017 km/s
Details[2]
γ CMi A
Mass	1.88 M☉
Radius	36.8±2.6 R☉
Luminosity	321±33 L☉
Temperature	4,036±100 K
Rotational velocity (v sin i)	5±2 km/s
Age	1.3 Gyr
γ CMi B
Mass	1.85 M☉
Radius	7.8±1.0 R☉
Luminosity	25.4±5.2 L☉
Temperature	4,658±200 K
Rotational velocity (v sin i)	2.0±2.0 km/s
Other designations
γ CMi, 4 CMi, BD+09°1660, GC 9974, HD 58972, HIP 36284, HR 2854, SAO 115478, ADS 6100, CCDM 07281+0856, WDS J07282+0856A[6]
Database references
SIMBAD	data

This spectroscopic binary star system has an orbital period of 389.31 days, a semimajor axis of 1.48 AU, and an eccentricity of 0.2586.[2] Their variable radial velocity was discovered by H. M. Reese in 1902 at Lick Observatory.[8] Both components are evolved, K-type giant stars, most likely on their first ascent along the red giant branch. The primary, component A, has a stellar classification of K4 III while the secondary, component B, may be K1: III.[2]

References

1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
2. Fekel, F. C.; et al. (March 2013), "The spectroscopic orbit of the K-giant binary γ Canis Minoris", Astronomische Nachrichten, 334 (3): 223, Bibcode:2013AN....334..223F, CiteSeerX 10.1.1.300.8819, doi:10.1002/asna.201211842.
3. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
4. Johnson, H. L. (1966), "UBVRIJKL Photometry of the Bright Stars", Communications of the Lunar and Planetary Laboratory, 4: 99, Bibcode:1966CoLPL...4...99J.
5. 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
6. "gam CMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-03.
7. Kambič, Bojan (2009). Viewing the Constellations with Binoculars: 250+ Wonderful Sky Objects to See and Explore. Springer. p. 32. ISBN 978-0387853543.
8. Campbell, W. W. (September 1902), "Six stars whose velocities in the line of sight are variable", Astrophysical Journal, 16: 114–117, Bibcode:1902ApJ....16..114C, doi:10.1086/140954.