HD 203473
| Observation data Epoch J2000 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus[1] |
| Right ascension | 21h 22m 18.87390s[2] |
| Declination | +05° 01′ 24.9072″[2] |
| Apparent magnitude (V) | 8.23[1] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G6 V[3] |
| B−V color index | +0.66[1] |
| Astrometry | |
| Radial velocity (Rv) | −61.70±0.13[2] km/s |
| Proper motion (μ) | RA: 180.093±0.035 mas/yr[2] Dec.: 0.098±0.031 mas/yr[2] |
| Parallax (π) | 13.7402±0.0370 mas[2] |
| Distance | 237.4 ± 0.6 ly (72.8 ± 0.2 pc) |
| Absolute magnitude (MV) | +4.2[1] |
| Details | |
| Mass | 1.12[4] M☉ |
| Radius | 1.52[5] R☉ |
| Luminosity | 2.31[5] L☉ |
| Surface gravity (log g) | 4.11[4] cgs |
| Temperature | 5,780[5] K |
| Metallicity [Fe/H] | +0.19[4] dex |
| Rotation | 28 days[6] |
| Rotational velocity (v sin i) | 1.27[6] km/s |
| Age | 6.0[6] Gyr |
| Other designations | |
| AG+04°2898, BD+04°4656, HD 203473, HIP 105521, SAO 126740, GSC 00536-00696 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 203473 is a star in the equatorial constellation Equuleus. With an apparent magnitude of 8.23,[1] it’s only visible by using an amateur telescope. The star is located at a distance of 237 light years[2] based on its parallax shift but is drifting closer at a high rate of 61.7 km/s.[2] As of 2014, no stellar companions have been detected around the star.[7]
HD 203473 is an ordinary G-type main-sequence star with 112% the mass of the Sun,[4] but is 52% larger than the latter.[5] This star is over luminous and hot for its reported spectral class, with it radiating at 2.3 times the luminosity of the Sun and an effective temperature of 5,780 K.[5] HD 203473 is about six billion years old.[6] Like many planetary hosts, HD 203473 has an enhanced metallicity, with an iron abundance 1.55 times that of the Sun.[4]
Companion
In 2018, the N2K project discovered an object, initially thought to be a planet, orbiting the star via Doppler spectroscopy. Due to the detection method, its inclination and true mass were initially unknown.[8] In 2022, the inclination and true mass of this companion were measured via astrometry, revealing it to be 96 MJ and thus either a massive brown dwarf or low-mass star. The companion's orbital period was also found to be twice as long as originally thought.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 95.886+8.523 −8.864 MJ |
4.161+0.172 −0.190 |
8.103+0.014 −0.016 |
0.404±0.007 | 141.240+0.949 −0.909° |
— |
References
- ^ a b c d e 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. XHIP record for this object at VizieR.
- ^ a b c d e f g h 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.
- ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 05: 0. Bibcode:1999MSS...C05....0H.
- ^ a b c d e Xiao, Guang-Yao; Liu, Yu-Juan; Teng, Huan-Yu; Wang, Wei; Brandt, Timothy D.; Zhao, Gang; Zhao, Fei; Zhai, Meng; Gao, Qi (2023). "The Masses of a Sample of Radial-velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics. 23 (5). arXiv:2303.12409. Bibcode:2023RAA....23e5022X. doi:10.1088/1674-4527/accb7e.
- ^ a b c d e Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467.
- ^ a b c d Tejada Arevalo, Roberto A.; Winn, Joshua N.; Anderson, Kassandra R. (2021). "Further Evidence for Tidal Spin-up of Hot Jupiter Host Stars". The Astrophysical Journal. 919 (2): 138. arXiv:2107.05759. Bibcode:2021ApJ...919..138T. doi:10.3847/1538-4357/ac1429.
- ^ Tokovinin, Andrei (2014-04-01). "From Binaries to Multiples. I. Data on F and G Dwarfs within 67 pc of the Sun". The Astronomical Journal. 147 (4): 86. arXiv:1401.6825. Bibcode:2014AJ....147...86T. doi:10.1088/0004-6256/147/4/86. ISSN 0004-6256. S2CID 53965918.
- ^ Ment, Kristo; Fischer, Debra A.; Bakos, Gaspar; Howard, Andrew W.; Isaacson, Howard (2018-11-01). "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. ISSN 0004-6256. S2CID 119243619.
- ^ 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.