HD 179079 is a star with an exoplanetary companion in the equatorial constellation of Aquila. It has an apparent visual magnitude of approximately 7.96, making it too faint to be readily visible to the naked eye. The distance to this star can be determine using parallax measurements, which yields an estimate of approximately 228 light years. It is drifting further away with a radial velocity of +20 km/s.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 11m 09.8287s[1] |
| Declination | −02° 38′ 18.1871″[1] |
| Apparent magnitude (V) | 7.95[2] |
| Characteristics | |
| Spectral type | G5IV[2] |
| Apparent magnitude (B) | 8.694[3] |
| Apparent magnitude (J) | 6.734±0.021[3] |
| Apparent magnitude (H) | 6.402±0.031[3] |
| Apparent magnitude (K) | 6.311±0.026[3] |
| B−V color index | 0.744±0.013[3] |
| Astrometry | |
| Radial velocity (Rv) | 19.73±0.20[1] km/s |
| Proper motion (μ) | RA: −134.422±0.125[1] mas/yr Dec.: −89.424±0.104[1] mas/yr |
| Parallax (π) | 14.3167 ± 0.0809 mas[1] |
| Distance | 228 ± 1 ly (69.8 ± 0.4 pc) |
| Absolute magnitude (MV) | 3.87[3] |
| Details | |
| Mass | 1.05±0.02 M☉[4] 1.25±0.09 M☉[2] 1.15±0.03[5] M☉ |
| Radius | 1.45±0.09 R☉[4] 1.792±0.016 R☉[2] 1.60±0.09[5] R☉ |
| Luminosity | 2.34 L☉[4] 2.41±0.27[5] L☉ |
| Surface gravity (log g) | 4.11±0.04[2] cgs |
| Temperature | 5,672±14[4] K |
| Metallicity [Fe/H] | 0.19±0.03[4] dex |
| Rotational velocity (v sin i) | 1.00±0.52[4] km/s |
| Age | 7.88±0.65[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is an evolved G-type subgiant star with a stellar classification of G5IV.[2] It is nearly 7–8[4] billion years old and is chromospherically inactive[5] with a projected rotational velocity of 1 km/s.[4] The evolutionary track for this star implies a mass slightly higher than the Sun. It is larger in radius than the Sun and has a higher metallicity; the abundance of elements in the star's atmosphere with higher atomic numbers than hydrogen and helium. HD 179079 is radiating about 2.3[4] times the luminosity of the Sun from its photosphere at an effective temperature of 5,672 K.[4]
Planetary system
editAn exoplanet, HD 179079 b, was announced in August 2009 to be orbiting this star. The planet was detected by the radial velocity method, using the HIRES spectrometer at Keck Observatory.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.076±0.012 MJ | 0.1214+0.0064 −0.0071 |
14.4808+0.01 −0.0035 |
0.049±0.087 | — | — |
See also
editReferences
edit- ^ a b c d e f g 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.
- ^ a b c d e f g Hill, Michelle L.; et al. (2020). "Orbital Refinement and Stellar Properties for the HD 9446, HD 43691, and HD 179079 Planetary Systems". The Astronomical Journal. 159 (5): 197. arXiv:2003.02385. Bibcode:2020AJ....159..197H. doi:10.3847/1538-3881/ab7d33. S2CID 212414679.
- ^ a b c d e f 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.
- ^ a b c d e f g h i j k 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.
- ^ a b c d e Valenti, Jeff A.; et al. (2009). "Two Exoplanets Discovered at Keck Observatory". The Astrophysical Journal. 702 (2): 989–997. arXiv:0908.1612. Bibcode:2009ApJ...702..989V. doi:10.1088/0004-637X/702/2/989. S2CID 16707072.
- ^ HIP 94256 -- Star, database entry, SIMBAD. Accessed on line September 2, 2009.
- ^ Ment, Kristo; et al. (2018). "Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810". The Astronomical Journal. 156 (5). 213. arXiv:1809.01228. Bibcode:2018AJ....156..213M. doi:10.3847/1538-3881/aae1f5. S2CID 119243619.