HD 190647

HD 190647

Observation data Epoch J2000      Equinox J2000
Constellation	Sagittarius
Right ascension	20^h 07^m 19.6698^s[1]
Declination	−35° 32′ 19.0786″[1]
Apparent magnitude (V)	7.78[2]
Characteristics
Spectral type	G5V[3]
B−V color index	0.743±0.002[2]
Variable type	Constant[4]
Astrometry
Radial velocity (Rv)	−40.33±0.12[1] km/s
Proper motion (μ)	RA: −26.622±0.079[1] mas/yr Dec.: −206.859±0.053[1] mas/yr
Parallax (π)	18.3287 ± 0.0495 mas[1]
Distance	177.9 ± 0.5 ly (54.6 ± 0.1 pc)
Absolute magnitude (MV)	4.00[2]
Details
Mass	1.07±0.01[5] M☉
Radius	1.56±0.03[5] R☉
Luminosity	2.19±0.01[5] L☉
Surface gravity (log g)	4.07±0.02[5] cgs
Temperature	5,630+48 −40[5] K
Metallicity [Fe/H]	0.23[6] dex
Rotational velocity (v sin i)	1.576[6] km/s
Age	8.7±0.4[5] Gyr
Other designations
CD–35°13924, HD 190647, HIP 99115, SAO 211821, LTT 7948, NLTT 48727, TYC 7449-1245-1, 2MASS J20071966-3532189[7]
Database references
SIMBAD	data

HD 190647 is a yellow-hued star with an exoplanetary companion, located in the southern constellation of Sagittarius. It has an apparent visual magnitude of 7.78,[2] making this an 8th magnitude star that is much too faint to be readily visible to the naked eye. The star is located at a distance of 178 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −40 km/s.[1] It is also called HIP 99115.

The stellar classification of this star is G5V,[3] matching a G-type main-sequence star. However, the low gravity and high luminosity of this star may indicate it is slightly evolved. It is chrompsherically inactive with a slow rotation,[4] having a projected rotational velocity of 1.6 km/s.[6] The star's metallicity is high, with nearly 1.5 times the abundance of iron compared to the Sun.[4]

In 2007, a Jovian planet was found to be orbiting the star. It was detected using the radial velocity method with the HARPS spectrograph in Chile. The object is orbiting at a distance of 2.0 AU from the host star with a period of 2.84 years and an eccentricity (ovalness) of 0.18. As the inclination of the orbital plane is unknown, only a lower bound on the planetary mass can be made. It has a minimum mass 1.9 times the mass of Jupiter.[4]

The HD 190647 planetary system[4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	>1.9 ± 0.06 MJ	2.07 ± 0.06	1038.1 ± 4.9	0.18 ± 0.02	—	—

See also

• HD 100777
• HD 221287
• 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: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
4. Naef, M.; et al. (2007). "The HARPS search for southern extra-solar planets. IX. Exoplanets orbiting HD 100777, HD 190647, and HD 221287". Astronomy and Astrophysics. 470 (2): 721–726. arXiv:0704.0917. Bibcode:2007A&A...470..721N. doi:10.1051/0004-6361:20077361.
5. Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
6. Costa Silva, A. R.; et al. (February 2020). "Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur". Astronomy & Astrophysics. 634: 10. arXiv:1912.08659. Bibcode:2020A&A...634A.136C. doi:10.1051/0004-6361/201936523. S2CID 209405391. A136.
7. "HD 190647". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-11.