HD 8673 is a binary star in the northern constellation of Andromeda. It has an apparent magnitude and absolute magnitude of 6.34 and 3.56 respectively.[2] Based upon an annual parallax shift of 26.2 mas, the system is located around 124.5 light years away. The system is moving further from the Earth with a heliocentric radial velocity of +19 km/s.[1] A sub-stellar companion was detected in 2005; it could either be an exoplanet or a brown dwarf.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 01h 26m 08.78637s[1] |
| Declination | +34° 34′ 46.9318″[1] |
| Apparent magnitude (V) | 6.34[2] |
| Characteristics | |
| Spectral type | F7 V + M2 V[3] |
| B−V color index | 0.500±0.004[2] |
| Astrometry | |
| Radial velocity (Rv) | 19.08±0.14[1] km/s |
| Proper motion (μ) | RA: 236.271±0.030 mas/yr[1] Dec.: −84.632±0.022 mas/yr[1] |
| Parallax (π) | 26.2036 ± 0.0370 mas[1] |
| Distance | 124.5 ± 0.2 ly (38.16 ± 0.05 pc) |
| Absolute magnitude (MV) | 3.56[2] |
| Orbit[3] | |
| Semi-major axis (a) | 35–60 AU |
| Eccentricity (e) | < 0.5 |
| Inclination (i) | 75–85° |
| Details[4] | |
| HD 8673 A | |
| Mass | 1.36±0.20 M☉ |
| Radius | 1.521±0.049 R☉ |
| Luminosity | 3.37+0.51 −0.44 L☉ |
| Surface gravity (log g) | 4.21 cgs |
| Temperature | 6,340 K |
| Metallicity [Fe/H] | 0.15 dex |
| Rotational velocity (v sin i) | 26.9 km/s |
| Age | 1.5+2.1 −0.6 Gyr |
| HD 8673 B | |
| Mass | 0.33–0.45[3] M☉ |
| Temperature | 3,520-3,690[3] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component is an F-type main-sequence star with a stellar classification of F7 V.[3] It has 1.36 times the mass of the Sun and 1.52 times the Sun's radius. The star is around 1.5 billion years old and is spinning with a projected rotational velocity of 26.9 km/s. It is radiating 3.4 times the Sun's luminosity from its photosphere at an effective temperature of 6,340 K.[4]
Speckle interferometry measurements of this star between 2001 and 2008 showed a candidate stellar companion to this star, announced in 2011. It was unclear whether the pair formed a visual double or a binary system. The authors of the study estimated a class of K2 V, based upon a visual magnitude difference of 2.3±0.5.[6] Subsequent observations using adaptive options did not spot this companion and it was concluded this was a false detection. However, a low mass stellar companion was detected in a wide orbit. This red dwarf star has 0.33–0.45 times the mass of the Sun and is orbiting with a semimajor axis of 35–60 AU.[3]
Planetary system
editAn orbiting sub-stellar companion with a minimum mass 14 times that of Jupiter in a high-eccentricity orbit was discovered in 2005 and confirmed in 2010. This object orbits at 3 AU away from the primary star with a period of 1,634 days and an eccentricity of 0.7.[7] In 2022, the inclination and true mass of HD 8673 Ab were measured via astrometry.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 13.248+1.688 −1.416 MJ |
2.970+0.147 −0.171 |
4.503+0.030 −0.043 |
0.730+0.042 −0.026 |
95.450+19.444 −8.816° |
— |
References
edit- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d 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 Roberts, Lewis C.; et al. (2015). "Know the Star, Know the Planet. IV. A Stellar Companion to the Host Star of the Eccentric Exoplanet HD 8673b". The Astronomical Journal. 149 (4). 144. arXiv:1502.06630. Bibcode:2015AJ....149..144R. doi:10.1088/0004-6256/149/4/144. S2CID 29694924.
- ^ a b Valenti, J. A.; Fischer, D. A. (2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". The Astrophysical Journal Supplement Series. 159 (1): 141–166. Bibcode:2005ApJS..159..141V. doi:10.1086/430500.
- ^ "HD 6114". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 12, 2018.
- ^ Mason, Brian D.; et al. (November 2011). "Know the star, know the planet. II. Speckle interferometry of exoplanet host stars". The Astronomical Journal. 142 (5): 6. arXiv:1109.4569. Bibcode:2011AJ....142..176M. doi:10.1088/0004-6256/142/5/176. S2CID 16590094. 176.
- ^ Hartmann, Michael; et al. (2010). "A Sub-stellar Companion around the F7 V Star HD 8673". The Astrophysical Journal. 717 (1): 348–356. Bibcode:2010ApJ...717..348H. doi:10.1088/0004-637X/717/1/348.
- ^ a b Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.
External links
edit- "Notes for planet HD 8673 b". Extrasolar Planets Encyclopaedia. Archived from the original on September 21, 2010. Retrieved December 21, 2007.
- Hatzes; et al. (2005). "The first extrasolar planets from the TOPS program: a superplanet around a massive evolved star and an F7 star" (PDF). Geophysical Resource Abstract. 7. Retrieved December 21, 2007.