HD 117207

HD 117207 is a star in the southern constellation Centaurus. With an apparent visual magnitude of 7.24,[2] it is too dim to be visible to the naked eye but can be seen with a small telescope. Based upon parallax measurements, it is located at a distance of 105.6 light years from the Sun. The star is drifting closer with a radial velocity of −17.4 km/s.[4] It has an absolute magnitude of 4.67.[4]

HD 117207

Observation data Epoch J2000      Equinox J2000
Constellation	Centaurus
Right ascension	13^h 29^m 21.11298^s[1]
Declination	−35° 34′ 15.5863″[1]
Apparent magnitude (V)	7.240[2]
Characteristics
Spectral type	G7IV-V[3]
B−V color index	0.727±0.014[2]
Astrometry
Radial velocity (Rv)	−17.43±0.09[4] km/s
Proper motion (μ)	RA: −205.954±0.079[1] mas/yr Dec.: −71.515±0.079[1] mas/yr
Parallax (π)	30.8785 ± 0.0496[1] mas
Distance	105.6 ± 0.2 ly (32.38 ± 0.05 pc)
Absolute magnitude (MV)	4.67[4]
Details[2]
Mass	1.053±0.028 M☉
Radius	1.074±0.041 R☉
Luminosity	1.163+0.002 −0.003[1] L☉
Surface gravity (log g)	4.371±0.039 cgs
Temperature	5,732±53 K
Metallicity [Fe/H]	0.19±0.03 dex
Age	4.192±2.274[2] Gyr
Other designations
CPD−34°8913, HD 117207, HIP 65808, SAO 204517[5]
Database references
SIMBAD	data
Extrasolar Planets Encyclopaedia	data

This object has a stellar classification of G7IV-V,[3] showing blended spectral traits of a G-type main-sequence star and an older, evolving subgiant star. It is around four[2] billion years old with 5%[6] greate mass than the Sun and a 7% larger radius.[1] The star is radiating 1.16 times the luminosity of the Sun from its photosphere at an effective temperature of 5,644 K.[1]

In 2005, a planet was found orbiting the star using the radial velocity method, and was designated HD 117207 b.[7][8] The orbital elements of this planet were refined in 2018, showing an orbital period of 7.18 years, a semimajor axis of 3.79 AU, and an eccentricity of 0.16. The minimum mass of this object is nearly double that of Jupiter. If an inner planet is orbiting the star, it must have an orbital period no greater than 3.46 years to satisfy Hill's criteria for dynamic stability.[2]

The HD 117207 planetary system[2]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥1.926±0.034 MJ	3.787+0.034 −0.035	2,621.75+8.37 −8.53	0.157±0.013	—	—

See also

• HD 117618
• 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. Barbato, D.; et al. (August 2018). "Exploring the realm of scaled solar system analogues with HARPS". Astronomy & Astrophysics. 615: 21. arXiv:1804.08329. Bibcode:2018A&A...615A.175B. doi:10.1051/0004-6361/201832791. A175.
3. Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
4. 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.
5. "HD 117207". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-23.
6. Luck, R. Earle (March 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 31. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. 111.
7. Marcy, Geoffrey W.; et al. (2005). "Five New Extrasolar Planets". The Astrophysical Journal. 619 (1): 570–584. Bibcode:2005ApJ...619..570M. CiteSeerX 10.1.1.516.6667. doi:10.1086/426384.
8. Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701.