Omicron Capricorni - Misplaced Pages

Star in the constellation Capricornus

Omicron Capricorni
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Location of ο Capricorni (circled)
Constellation	Capricornus
ο Cap A
Right ascension	20 29 53.91117
Declination	−18° 34′ 59.4803″
Apparent magnitude (V)	+5.94
ο Cap B
Right ascension	20 29 52.59487
Declination	−18° 35′ 10.7447″
Apparent magnitude (V)	+6.74
Characteristics
ο Cap A
Spectral type	A1 V
U−B color index	+0.30
B−V color index	+0.08
ο Cap B
Spectral type	A7/8 V
U−B color index	+0.04
B−V color index	+0.22
Astrometry
ο Cap A
Radial velocity (R_v)	−12.4±1.3 km/s
Proper motion (μ)	RA: +31.70 mas/yr Dec.: −83.18 mas/yr
Parallax (π)	15.07 ± 4.14 mas
Distance	approx. 220 ly (approx. 70 pc)
ο Cap B
Radial velocity (R_v)	−9.1±0.6 km/s
Proper motion (μ)	RA: +33.31 mas/yr Dec.: −66.16 mas/yr
Details
ο Cap A
Mass	2.05±0.20 `M`_☉
Luminosity	18.6 `L`_☉
Surface gravity (log g)	4.23 cgs
Temperature	10,492±357 K
Rotational velocity (v sin i)	276 km/s
Age	118 Myr
ο Cap B
Mass	1.34±0.24 `M`_☉
Temperature	7,762 K
Rotational velocity (v sin i)	136 km/s
Other designations
ο Cap, 12 Cap, ADS 13902, CCDM J20299-1835
ο Cap A: BD−19° 5831, GC 28503, HD 195094, HIP 101123, HR 7830, SAO 163626
ο Cap B: BD−19° 5830, GC 28502, HD 195093, HIP 101120, HR 7829, SAO 163625
Database references
SIMBAD	A
	B

Omicron Capricorni (ο Capricorni) is a wide binary star system in the constellation Capricornus. The brighter component has an apparent visual magnitude of +5.94, which is near the lower limit on stellar brightness that still can be seen with the naked eye. Based upon an annual parallax shift of 15.07 mas as seen from Earth, this system is located roughly 220 light-years from the Sun. Large but uncertain discrepancies in the parallax measurements from Hipparcos may indicate, weakly, that there is a third, unseen companion in the system.

Both visible components are white-hued A-type main-sequence stars. The primary, component A, sometimes called ο Capricorni, has an apparent magnitude of +5.94, while the companion, component B or ο Capricorni, has an apparent magnitude of +6.74. The two stars are currently separated by 21.91 arcseconds, corresponding to a projected separation of around 2,100 AU. At the estimated age of around 118 million years old, both components are spinning rapidly: component A has a projected rotational velocity of 276 km/s, while component B is 136 km/s.

References

^ 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, S2CID 18759600.
^ 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.
^ Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
^ Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
^ 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, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
"omi Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-31.
"omi Cap A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-31.
"omi Cap B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-31.
^ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
Harvard College Observatory (1941). Sky and Telescope. Stanford University.
Abt, Helmut A. (August 1988), "Maximum Separations among Cataloged Binaries", Astrophysical Journal, 331: 922, Bibcode:1988ApJ...331..922A, doi:10.1086/166609.

Constellation of Capricornus

Stars

Bayer	α (Prima Giedi) α (Algedi) β (Dabih) β γ (Nashira) δ (Deneb Algedi) ε ζ η θ ι κ λ μ ν (Alshat) ξ ξ ο ο π ρ σ τ τ υ φ χ ψ ω
Flamsteed	3 4 17 19 20 21 24 (A) 27 29 30 31 33 35 36 (b) 37 41 42 44 45 46 (c) 47 (c) 50
Variable	R
HR	7722 7845 7898
HD	197027 202206 204313
Other	HATS-3 LP 816-60

Exoplanets	HD 192310 b c HD 202206 c HD 204313 b HD 202772 Ab PSO J318.5−22

Star clusters	Messier 30 Palomar 12

Galaxies

NGC	6907 7016 7019 7030 7035 7035A 7073
Other	IC 1337 PKS 2126-158

Galaxy clusters	HCG 87