Astronomy:HD 170469
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Ophiuchus[1] |
| Right ascension | 18h 29m 10.98109s[2] |
| Declination | +11° 41′ 43.8033″[2] |
| Apparent magnitude (V) | 8.21[3] |
| Characteristics | |
| Evolutionary stage | subgiant[4] + main sequence |
| Spectral type | G5IV[5] + K5V[6] |
| B−V color index | 0.677±0.014[3] |
| Astrometry | |
| Radial velocity (Rv) | −59.32±0.10[6] km/s |
| Proper motion (μ) | RA: −48.277[2] mas/yr Dec.: −17.791[2] mas/yr |
| Parallax (π) | 16.5732 ± 0.0231[2] mas |
| Distance | 196.8 ± 0.3 ly (60.34 ± 0.08 pc) |
| Absolute magnitude (MV) | 4.23[3] |
| Orbit[7] | |
| Period (P) | 114000 yr |
| Semi-major axis (a) | 43.1″ |
| Details | |
| A | |
| Mass | 1.10[8] M☉ |
| Radius | 1.24[8] R☉ |
| Luminosity | 1.639±0.006[9] L☉ |
| Surface gravity (log g) | 4.30±0.03[8] cgs |
| Temperature | 5,786±28[6] K |
| Metallicity [Fe/H] | 0.28±0.02[6] dex |
| Rotation | 30.46±0.16 or 33.14±0.24 d[4] |
| Age | 4.8+3.0 −0.5[3] or 8.6±0.5[10] Gyr |
| B | |
| Mass | 0.42[11] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 170469 is a probable binary star[11][7] 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.[3] 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,[6] and is expected to come to within 49.8 light-years in about 959,000 years.
The primary, component A, is a G-type subgiant[4] with a stellar classification of G5IV,[5] indicating it is generating energy through core hydrogen fusion. Estimates of the star's age range from five[3] to almost nine[10] billion years. It has 1.10 times the mass of the Sun and 1.24 times the Sun's radius.[8] The star has a higher than solar metallicity.[6] It is radiating 1.64[9] times the Sun's luminosity from its photosphere at an effective temperature of 5,786 K.[6]
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.[6] Initially it was thought to be a red dwarf of spectral class M1,[7] but was later determined to be a K-type main-sequence star with a class of K5V.[6] This star lies at a projected separation of 2708 astronomical unit|AU[7] from the primary, and is orbiting with an estimated period of around 114,000 years.[11]
Planetary system
In 2007, a gas giant exoplanet was discovered around the primary star by the N2K Consortium, led by principal investigators Debra Fischer and Gregory P. Laughlin.[5] It was spotted using the radial velocity method, and was independently confirmed in 2014.[7] Its minimum mass is a third that of Jupiter, and it orbits at just over twice Earth's distance from the Sun, taking three Earth years to complete an orbit.[5]
A 2026 study using HARPS-N found weak evidence for a potential candidate second planet, which would be a hot Neptune orbiting with an 8-day period.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| .01[4] (unconfirmed) | ≥13.8±3.2 M⊕ | — | 8.2676±0.0015 | 0.19+0.26 −0.13 |
— | — |
| b[5] | ≥0.67 MJ | 2.1 | 1,145±18 | 0.11±0.08 | — | — |
See also
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 4.0 4.1 4.2 4.3 4.4 Ruggieri, A. et al. (July 2026). "The GAPS Programme with HARPS-N at TNG LXXVII. Occurrence rates of small close-in planets in the presence of cold Jupiters". Astronomy & Astrophysics.
- ↑ 5.0 5.1 5.2 5.3 5.4 Fischer, Debra A. et al. (2007). "Five Intermediate-Period Planets from the N2K Sample". The Astrophysical Journal 669 (2): 1336–1344. doi:10.1086/521869. Bibcode: 2007ApJ...669.1336F.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 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. doi:10.1093/mnras/sty1295. Bibcode: 2018MNRAS.479.1332M.
- ↑ 7.0 7.1 7.2 7.3 7.4 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. doi:10.1093/mnras/stu044. Bibcode: 2014MNRAS.439.1063M.
- ↑ 8.0 8.1 8.2 8.3 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. doi:10.3847/1538-3881/aa5df3. Bibcode: 2017AJ....153..136S.
- ↑ 9.0 9.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 10.0 10.1 Bonfanti, A. et al. (March 2015). "Revising the ages of planet-hosting stars". Astronomy & Astrophysics 575: 17. doi:10.1051/0004-6361/201424951. A18. Bibcode: 2015A&A...575A..18B.
- ↑ 11.0 11.1 11.2 Tokovinin, Andrei (2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal 147 (4): 87. doi:10.1088/0004-6256/147/4/87. Bibcode: 2014AJ....147...87T.
- ↑ "HD 170469". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+170469.
Coordinates: 
18h 29m 10.9812s, +11° 41′ 43.7985″
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