HD 12139

HD 12139

Observation data Epoch J2000      Equinox J2000
Constellation	Aries
Right ascension	01^h 59^m 35.68295^s[1]
Declination	21° 03′ 30.8402″[1]
Apparent magnitude (V)	5.89[2]
Characteristics
Spectral type	K0III-IV[2]
B−V color index	1.03[2]
Astrometry
Radial velocity (Rv)	-1.97[2] km/s
Proper motion (μ)	RA: 140.10[1] mas/yr Dec.: -15.68[1] mas/yr
Parallax (π)	8.34 ± 0.84[1] mas
Distance	approx. 390 ly (approx. 120 pc)
Absolute magnitude (MV)	0.50
Other designations
BD+20° 322, HIP 9307, HR 577, SAO 75077.
Database references
SIMBAD	data
Data sources:
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.)
Database references
SIMBAD	data

HD 12139 is a double star in the constellation Aries. With an apparent magnitude of 5.89, the stars can be seen by the naked eye under good conditions in rural areas. The system is located approximately 120 parsecs (390 ly) distant, and the brighter star is a red giant, meaning that it has used up its core hydrogen and is expanding.^[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.Vizier catalog entry
2. "HR 378". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 22 June 2014.