Kappa Capricorni

Kappa Capricorni (κ Cap, κ Capricorni) is a solitary[9] star in the constellation Capricornus. It is visible to the naked eye with an apparent visual magnitude of +4.73.[2] Based upon an annual parallax shift of 11.09 mas as seen from the Earth,[1] the star is located about 294 light years from the Sun.

κ Capricorni

Location of κ Capricorni (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Capricornus
Right ascension	21^h 42^m 39.50710^s[1]
Declination	−18° 51′ 58.7669″[1]
Apparent magnitude (V)	+4.73[2]
Characteristics
Spectral type	G8 III[3]
U−B color index	+0.51[2]
B−V color index	+0.88[2]
Astrometry
Radial velocity (Rv)	−2.87±0.18[4] km/s
Proper motion (μ)	RA: +145.85[1] mas/yr Dec.: −9.50[1] mas/yr
Parallax (π)	11.09 ± 0.28[1] mas
Distance	294 ± 7 ly (90 ± 2 pc)
Absolute magnitude (MV)	−0.023[5]
Details[6]
Mass	2.43±0.21 M☉
Radius	13.28±0.47 R☉
Luminosity	106.8±5.9 L☉
Surface gravity (log g)	2.59±0.06 cgs
Temperature	5,096±57 K
Metallicity [Fe/H]	−0.39±0.10 dex
Rotational velocity (v sin i)	0.0[4] km/s
Age	1.19[7] Gyr
Other designations
κ Cap, 43 Cap, BD−19° 6152, HD 206453, HIP 107188, HR 8288, SAO 164593[8]
Database references
SIMBAD	data

This is a yellow-hued, evolved, G-type giant star with a stellar classification of G8 III.[3] There is a 91% probability that it is currently on the horizontal branch, rather than the red giant branch.[6] As such, it is a red clump[10] giant with an estimated 2.43 times the mass of the Sun and has expanded to 13.28 times the radius of the Sun.[6] The star is about 1.2[7] billion years old and has a projected rotational velocity that is too small to be measured.[4] It radiates 107 times the solar luminosity from its photosphere at an effective temperature of 5,096 K.[6]

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. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
3. Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars, 4, Bibcode:1988mcts.book.....H.
4. Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
5. Soubiran, C.; et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics, 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788.
6. 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, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360, hdl:10722/215277. Values are based on 91% probability it is on the horizontal branch.
7. Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88.
8. "kap Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-05-13.
9. 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.
10. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278.