Astronomy:HD 233731
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Ursa Major[1] |
| Right ascension | 10h 22m 43.5923s[2] |
| Declination | +50° 07′ 42.062″[2] |
| Apparent magnitude (V) | 9.732[3] |
| Characteristics | |
| Spectral type | G5V[4] |
| B−V color index | 0.86[4] |
| Astrometry | |
| Radial velocity (Rv) | 12.86(15)[2] km/s |
| Proper motion (μ) | RA: −26.110(14)[2] mas/yr Dec.: 83.806(16)[2] mas/yr |
| Parallax (π) | 12.2731 ± 0.0155[2] mas |
| Distance | 265.7 ± 0.3 ly (81.5 ± 0.1 pc) |
| Absolute magnitude (MV) | 5.22±0.14[3] |
| Details[4] | |
| Mass | 0.936+0.028 −0.033 M☉ |
| Radius | 1.062+0.046 −0.013 R☉ |
| Luminosity | 0.77±0.09[3] L☉ |
| Surface gravity (log g) | 4.357+0.039 −0.005 cgs |
| Temperature | 5,314±50 K |
| Metallicity [Fe/H] | 0.30±0.09 dex |
| Rotation | 28.7±0.4 d |
| Rotational velocity (v sin i) | 1.65±0.26 km/s |
| Age | 9.0+1.4 −2.2 Gyr[4] 12.4±2.6[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 233731, or HAT-P-22, is a suspected multiple star system in the northern circumpolar constellation of Ursa Major. It is invisible to the naked eye, having an apparent visual magnitude of 9.732.[3] This system is located at a distance of 267 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +13 km/s.[2]
The stellar classification of the primary is G5V,[4] matching an ordinary G-type main-sequence star. The star has a low level of stellar activity with an estimated age of 9 to 12 billion years old. Its metallicity is twice that of the Sun, unusual for its advanced age.[4] HD 233731 has a similar mass and radius as the Sun, and is spinning with a rotation period of 28.7 days.[4] It is radiating 77%[3] of the luminosity of the Sun from its photosphere at an effective temperature of 5314 K.[4]
A faint stellar companion (2MASS J10224397+5007504) with a red hue is located at an angular separation of 9 arcseconds from the primary.[3] In 2015, a spectroscopic stellar companion was reported with a semimajor axis of less than 33 astronomical unit|AU. This star has an effective temperature of 4,000+250
−400 K with a mass of 0.63+0.07
−0.17 M☉.[6]
Planetary system
In 2010 a transiting hot Jupiter like planet was detected, designated HAT-P-22b.[3] It has an equilibrium temperature of 1,463±19 K, and planetary atmosphere is cloudy.[7] The measurement of Rossiter-McLaughlin effect in 2018 has allowed to detect what the planetary orbit is well aligned with the equatorial plane of the star, with a misalignment angle equal to 25°±18°.[4]
In 2017, analysis of additional HARPS data showed a long-term trend that suggested the presence of an additional orbiting companion, HAT-P-22c.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 2.192+0.073−0.013 MJ | 0.04171+0.00042−0.00050 | 3.21223328 | 0.016±0.009 | 86.46±0.41° | 1.060±0.048 RJ |
| c (unconfirmed) | ≥3.0 MJ | — | ≥20.8 years | — | — | — |
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 2.4 2.5 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 3.6 3.7 3.8 Bakos, G. Á. et al. (2010), "HAT-P-20b – HAT-P-23b: Four Massive Transiting Extrasolar Planets", The Astrophysical Journal 742 (2): 116, doi:10.1088/0004-637X/742/2/116, Bibcode: 2011ApJ...742..116B.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 Mancini, L. et al. (2018), "The GAPS programme with HARPS-N at TNG XVI. Measurement of the Rossiter-McLaughlin effect of transiting planetary systems HAT-P-3, HAT-P-12, HAT-P-22, WASP-39, and WASP-60", Astronomy & Astrophysics A41: 613, doi:10.1051/0004-6361/201732234, Bibcode: 2018A&A...613A..41M.
- ↑ "HD 233731". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+233731.
- ↑ Piskorz, Danielle et al. (2015), "Friends of Hot Jupiters. III. An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal 814 (2): 148, doi:10.1088/0004-637X/814/2/148, Bibcode: 2015ApJ...814..148P.
- ↑ Turner, Jake D. et al. (2016), "Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits", Monthly Notices of the Royal Astronomical Society 459 (1): 789–819, doi:10.1093/mnras/stw574, Bibcode: 2016MNRAS.459..789T.
- ↑ 8.0 8.1 Bonomo, A. S. et al. (2017), "The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets", Astronomy and Astrophysics 602: A107, doi:10.1051/0004-6361/201629882, Bibcode: 2017A&A...602A.107B.
Coordinates: 
10h 22m 43.5924s, +50° 07′ 42.0635″
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