HD 122430

HD 122430

Observation data Epoch J2000      Equinox J2000
Constellation	Hydra
Right ascension	14^h 02^m 22.78173^s[1]
Declination	−27° 25′ 47.1992″[1]
Apparent magnitude (V)	5.47[2]
Characteristics
Spectral type	K2–3III[3]
B−V color index	1.331±0.003[2]
Astrometry
Radial velocity (Rv)	−0.61±0.24[1] km/s
Proper motion (μ)	RA: −31.861±0.259[1] mas/yr Dec.: −4.195±0.215[1] mas/yr
Parallax (π)	7.3651 ± 0.1407 mas[1]
Distance	443 ± 8 ly (136 ± 3 pc)
Absolute magnitude (MV)	−0.17[2]
Details[4]
Mass	1.62±0.19 M☉
Radius	21.20±2.06 R☉
Luminosity	189.6±4.2[1] L☉
Surface gravity (log g)	1.96±0.07 cgs
Temperature	4,383±19 K
Metallicity [Fe/H]	−0.08±0.04 dex
Rotational velocity (v sin i)	2.59±0.45 km/s
Age	1.98±0.67 Gyr
Other designations
CD−26° 10060, GC 18954, HD 122430, HIP 68581, HR 5265, SAO 182182, GCRV 8247[5]
Database references
SIMBAD	data

HD 122430 is single star^[6] in the equatorial constellation of Hydra. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude of 5.47.^[2] The star is located at a distance of 105.6 light years from the Sun based on parallax.

This is an aging giant star with a stellar classification of K2–3III.^[3] It has completely run out of the hydrogen fuel that keeps it stable, although it is only two billion years old,^[4] younger than the Sun's 4.6 billion years. HD 122430 has a mass of 1.6 times and radius of 22.9 times that of the Sun.^[4] Despite its younger age, it has slightly lower metallicity, approximately 90%. It is radiating 190^[1] times the luminosity of the Sun from its photosphere at an effective temperature of 4300 K.^[4]

A candidate exoplanet was reported orbiting the star via the radial velocity method at a conference in 2003, and designated HD 122430 b. It has an orbital period of 0.94 years and an eccentricity of 0.68.^[7] However, a follow-up study by Soto et al. (2015) failed to detect a signal, so it remains unconfirmed.^[8]

The HD 122430 planetary system^[7]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b (unconfirmed)	>3.71 MJ	1.02	344.95±1.08	0.68±0.09	—	—

See also

• HD 47536
• List of extrasolar planets

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
3. Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 3. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
4. Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
5. "HD 117207". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-23.
6. 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.
7. Setiawan, J. (October 2003). Planets around evolved stars. Proceedings of the Conference on Towards Other Earths: DARWIN/TPF and the Search for Extrasolar Terrestrial Planets, 22–25 April 2003, Heidelberg, Germany. Vol. 539. Noordwijk, Netherlands: ESA Publications Division. pp. 595–598. Bibcode:2003ESASP.539..595S. ISBN 92-9092-849-2.
8. Soto, M. G.; et al. (August 2015). "RAFT - I. Discovery of new planetary candidates and updated orbits from archival FEROS spectra". Monthly Notices of the Royal Astronomical Society. 451 (3): 3131–3144. arXiv:1505.04796. Bibcode:2015MNRAS.451.3131S. doi:10.1093/mnras/stv1144.