HD 170469
HD 170469 is a probable binary star[7][4] system in the equatorial constellation of Ophiuchus. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.21.[2] The system is located at a distance of 197 light years away from the Sun based on parallax. It is drifting closer with a radial velocity of −59 km/s,[3] and is expected to come to within 49.8 light-years in about 959,000 years.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 18h 29m 10.98124s[1] |
| Declination | +11° 41′ 43.7985″[1] |
| Apparent magnitude (V) | 8.21[2] |
| Characteristics | |
| Spectral type | G5V + K5V[3] |
| B−V color index | 0.677±0.014[2] |
| Astrometry | |
| Radial velocity (Rv) | −59.32±0.10[3] km/s |
| Proper motion (μ) | RA: −48.418±0.070[1] mas/yr Dec.: −17.470±0.079[1] mas/yr |
| Parallax (π) | 16.5886 ± 0.0408[1] mas |
| Distance | 196.6 ± 0.5 ly (60.3 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.23[2] |
| Orbit[4] | |
| Primary | HD 170469 |
| Companion | HD 170469 B |
| Period (P) | 114000 yr |
| Semi-major axis (a) | 43.1″ |
| Details | |
| A | |
| Mass | 1.10[5] M☉ |
| Radius | 1.24[5] R☉ |
| Luminosity | 1.639±0.006[1] L☉ |
| Surface gravity (log g) | 4.30±0.03[5] cgs |
| Temperature | 5,786±28[3] K |
| Metallicity [Fe/H] | 0.28±0.02[3] dex |
| Age | 4.8+3.0 −0.5[2] or 8.6±0.5[6] Gyr |
| B | |
| Mass | 0.42[7] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary, component A, is a G-type main-sequence star with a stellar classification of G5V,[3] indicating it is generating energy through core hydrogen fusion. Estimates of the star's age range from five[2] to almost nine[6] billion years. It has 1.10 times the mass of the Sun and 1.24 times the Sun's radius.[5] The star has a higher than solar metallicity.[3] It is radiating 1.64[1] times the Sun's luminosity from its photosphere at an effective temperature of 5,786 K.[3]
The secondary companion, component B, is located at an angular separation of 43.21″±0.10″ along a position angle of 112.55°±0.07° from the primary, as of 2018.[3] Initially it was thought to be a red dwarf of spectral class M1,[4] but was later determined to be a K-type main-sequence star with a class of K5V.[3] This star lies at a projected separation of 2708 AU[4] from the primary, and is orbiting with an estimated period of around 114,000 years.[7]
Planetary system
In 2007, a planet was discovered by the N2K Consortium, led by principal investigators Debra Fischer and Gregory P. Laughlin.[9] It was spotted using the radial velocity method, and was independently confirmed in 2014.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.67 MJ | 2.24 | 1,143 | 0.11 | — | — |
References
- 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.
- 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.
- Montes, D.; et al. (September 2018). "Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K-primaries - I: High-resolution spectroscopy with HERMES: stellar parameters, abundances, and kinematics". Monthly Notices of the Royal Astronomical Society. 479 (1): 1332–1382. arXiv:1805.05394. Bibcode:2018MNRAS.479.1332M. doi:10.1093/mnras/sty1295. S2CID 119260219.
- Mugrauer, M.; et al. (March 2014). "New wide stellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 439 (1): 1063–1070. Bibcode:2014MNRAS.439.1063M. doi:10.1093/mnras/stu044.
- Stassun, Keivan G.; et al. (2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal. 153 (3): 136. arXiv:1609.04389. Bibcode:2017AJ....153..136S. doi:10.3847/1538-3881/aa5df3. S2CID 119219062.
- Bonfanti, A.; et al. (March 2015). "Revising the ages of planet-hosting stars". Astronomy & Astrophysics. 575: 17. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839. A18.
- Tokovinin, Andrei (2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal. 147 (4): 87. arXiv:1401.6827. Bibcode:2014AJ....147...87T. doi:10.1088/0004-6256/147/4/87. S2CID 56066740.
- "HD 170469". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-13.
- Fischer, Debra A.; et al. (2007). "Five Intermediate-Period Planets from the N2K Sample". The Astrophysical Journal. 669 (2): 1336–1344. arXiv:0704.1191. Bibcode:2007ApJ...669.1336F. doi:10.1086/521869. S2CID 7774321.