HD 203473
| Observation data Epoch J2000 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 22m 18.87390s |
| Declination | +05° 01′ 24.9072″ |
| Apparent magnitude (V) | 8.23 |
| Characteristics | |
| Evolutionary stage | subgiant |
| Spectral type | G6 V |
| B−V color index | +0.66 |
| Astrometry | |
| Radial velocity (Rv) | −61.70±0.13 km/s |
| Proper motion (μ) | RA: 180.093±0.035 mas/yr Dec.: 0.098±0.031 mas/yr |
| Parallax (π) | 13.7402±0.0370 mas |
| Distance | 237.4 ± 0.6 ly (72.8 ± 0.2 pc) |
| Absolute magnitude (MV) | +4.2 |
| Details | |
| Mass | 1.12 M☉ |
| Radius | 1.52 R☉ |
| Luminosity | 2.31 L☉ |
| Surface gravity (log g) | 4.11 cgs |
| Temperature | 5,780 K |
| Metallicity [Fe/H] | +0.19 dex |
| Rotation | 28 days |
| Rotational velocity (v sin i) | 1.27 km/s |
| Age | 6.0 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, it’s only visible by using an amateur telescope. The star is located at a distance of 237 light years based on its parallax shift but is drifting closer at a high rate of 61.7 km/s. As of 2014, no stellar companions have been detected around the star.
HD 203473 is an ordinary G-type main-sequence star with 112% the mass of the Sun, but is 52% larger than the latter. 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. HD 203473 is about six billion years old. Like many planetary hosts, HD 203473 has an enhanced metallicity, with an iron abundance 1.55 times that of the Sun.
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. 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.
| 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
- 1 2 3 4 5 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.
- 1 2 3 4 5 6 7 8 9 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.
- 1 2 3 4 5 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.
- 1 2 3 4 5 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.
- 1 2 3 4 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.
- 1 2 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.
