HD 220773
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus[1]
Right ascension 23h 26m 27.445s[2]
Declination +08° 38′ 37.84″[2]
Apparent magnitude (V) 7.10[1]
Characteristics
Evolutionary stage main sequence
Spectral type G0 V[3] or F9 V[4]
B−V color index 0.602±0.005[1]
Astrometry
Radial velocity (Rv)−37.735±0.0009[5] km/s
Proper motion (μ) RA: 27.096 mas/yr[2]
Dec.: −222.458 mas/yr[2]
Parallax (π)19.7694 ± 0.0669 mas[2]
Distance165.0 ± 0.6 ly
(50.6 ± 0.2 pc)
Absolute magnitude (MV)3.57[1]
Details
Mass1.154±0.003[6] M☉
Radius1.73±0.02[6] R☉
Luminosity3.16±0.01[6] L☉
Surface gravity (log g)4.02±0.01[6] cgs
Temperature5,852±26[6] K
Metallicity [Fe/H]0.09±0.06[7] dex
Rotational velocity (v sin i)3.82±1.00[8] km/s
Age6.3±0.1[6] Gyr
Other designations
BD+07 5030, Gaia DR2 2761142326076104192, HD 220773, HIP 115697, SAO 128181, 2MASS J23262744+0838376[9]
Database references
SIMBADdata

HD 220773 is a star with an orbiting exoplanet in the northern constellation of Pegasus. It has an apparent visual magnitude of 7.10,[1] which is too faint to be visible with the naked eye. The distance to this system, as determined by parallax measurements, is 165 light years,[2] but it is drifting closer with a radial velocity of −37.7 km/s.[5] The star shows a high proper motion, traversing the celestial sphere at an angular rate of 0.187 arcsec yr−1.[10]

The spectrum of HD 220773 presents as a late type star F-type or early G-type main-sequence star with a stellar classification of F9 V[4] or G0 V,[3] respectively. It is older than the Sun, with an estimated age of 6.3 billion years,[6] and the magnetic activity in the chromosphere is at a low level.[7] The star has 15% greater mass than the Sun but the radius is 73% larger.[6] The abundance of iron, a measure of the star's metallicity, is slightly higher than solar.[7] It is radiating over three times the luminosity of the Sun from its photosphere at an effective temperature of 5,852 K.[6]

A survey in 2015 ruled out the existence of any additional stellar companions at projected distances from 31 to 337 astronomical units.[3]

Planetary system

The star is orbited by an exoplanet discovered in 2012. As the inclination of the orbital plane is unknown, only a lower bound on the mass can be determined. This object has at least 1.45 times the mass of Jupiter. It has a very eccentric orbit with a semimajor axis of around 5 AU, taking 10.2 years to complete an orbit.[7] If any inner terrestrial planets exist in the HD 220773 system, these must have eccentric orbits for the planetary system to remain stable over a long time period.[11]

The HD 220773 planetary system[12]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥1.45±0.3 MJ 4.94±0.2 3,724.7±463 0.51±0.1 — —

References

  1. 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. S2CID 119257644.
  2. 1 2 3 4 5 6 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.
  3. 1 2 3 Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340.
  4. 1 2 Wittrock, Justin M.; et al. (2017). "Exclusion of Stellar Companions to Exoplanet Host Stars". The Astronomical Journal. 154 (5): 184. arXiv:1709.05315. Bibcode:2017AJ....154..184W. doi:10.3847/1538-3881/aa8d69. S2CID 55789971.
  5. 1 2 Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv:1804.09370. Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID 52952408.
  6. 1 2 3 4 5 6 7 8 9 Bonfanti, A.; et al. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
  7. 1 2 3 4 Robertson, Paul; et al. (2012). "The McDonald Observatory Planet Search: New Long-period Giant Planets and Two Interacting Jupiters in the HD 155358 System". The Astrophysical Journal. 749 (1): 39. arXiv:1202.0265. Bibcode:2012ApJ...749...39R. doi:10.1088/0004-637X/749/1/39. S2CID 59273311.
  8. ↑ Tejada Arevalo, Roberto A.; et al. (October 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. 138.
  9. ↑ "HD 220773". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 September 2020.
  10. ↑ Luyten, W. J. (June 1995). "NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode:1995yCat.1098....0L.
  11. ↑ Antoniadou, Kyriaki I.; Libert, Anne-Sophie (2018). "Puzzling out the coexistence of terrestrial planets and giant exoplanets. The 2/1 resonant periodic orbits". Astronomy & Astrophysics. A60: 615. arXiv:1804.04936. Bibcode:2018A&A...615A..60A. doi:10.1051/0004-6361/201732058. S2CID 119231621.
  12. ↑ "Planet HD 220773 b". exoplanet.eu. Retrieved 2024-01-05.
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