HAT-P-15

HAT-P-15 / Berehynia
Observation data; Epoch J2000 Equinox J2000
Constellation	Perseus
Right ascension	04h 24m 59.5350s
Declination	+39° 27′ 38.313″
Apparent magnitude (V)	12.41
Characteristics
Spectral type	G5V
Variable type	planetary transit
Astrometry
Radial velocity (Rv)	31.21 km/s
Proper motion (μ)	RA: 14.233(21) mas/yr ; Dec.: −9.407(15) mas/yr
Parallax (π)	5.1856 ± 0.0166 mas
Distance	629 ± 2 ly ; (192.8 ± 0.6 pc)
Details
Mass	1.013±0.043 M☉
Radius	1.080±0.039 R☉
Luminosity	1.00±0.11 L☉
Surface gravity (log g)	4.38±0.03 cgs
Temperature	5684±25 K
Metallicity	0.272±0.031
Rotational velocity (v sin i)	2.0±0.5 km/s
Age	6.8+2.5; −1.6 Gyr
Other designations
	Berehynia, Gaia DR3 179498266829041664, TYC 2883-1687-1, GSC 02883-01687, 2MASS J04245952+3927382
Database references
SIMBAD	data

HAT-P-15 is a G-type main-sequence star about 630 light-years away. The star is older than Sun yet has a concentration of heavy elements roughly 190% of solar abundance.^[3] The star has no noticeable starspot activity.^[5]

The spectroscopic survey in 2015 have failed to find any stellar companions to it,^[6] yet imaging survey have identified a possibly two companion red dwarf stars at projected separations 1210 and 1370 AU, respectively.^[7]

The star was named Berehynia in December 2019 by Ukrainian amateur astronomers.^[8]

Planetary system

In 2010 a transiting hot superjovian planet b (named Tryzub in 2019^[8]) was detected. It has an equilibrium temperature of 904±20 K.^[2] An orbital simulation shows that any planets inward of the orbit of b would spiral inward and be destroyed within a time-span of less than a billion years.^[9] The planetary orbit is well aligned with the equatorial plane of the star, misalignment equal to 13±6 degrees.^[10]

The HAT-P-15 planetary system^[2]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b / Tryzub	1.946±0.066 $M$ _J	0.0964±0.0014	10.863502±0.000027	0.19±0.019	89.1±0.2°	1.072±0.043 $R$ _J

References

^ ^a ^b ^c ^d 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 Kovács, G.; Bakos, G. Á.; Hartman, J. D.; Torres, G.; Noyes, R. W.; Latham, D. W.; Howard, A. W.; Fischer, D. A.; Johnson, J. A.; Marcy, G. W.; Isaacson, H.; Sasselov, D. D.; Stefanik, R. P.; Esquerdo, G. A.; Fernandez, J. M.; Lázár, B. Béky J.; Papp, I.; Sári, P.; Sári, P. (2010), "HAT-P-15b: A 10.9-Day Extrasolar Planet Transiting a Solar-Type Star", The Astrophysical Journal, 724 (2): 866–877, arXiv:1005.5300, Bibcode:2010ApJ...724..866K, doi:10.1088/0004-637X/724/2/866, S2CID 119207125
^ ^a ^b Teske, Johanna K.; Thorngren, Daniel; Fortney, Jonathan J.; Hinkel, Natalie; Brewer, John M. (2019), "Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances", The Astronomical Journal, 158 (6): 239, arXiv:1912.00255, Bibcode:2019AJ....158..239T, doi:10.3847/1538-3881/ab4f79, S2CID 208527082
^ HAT-P-15 -- Star
^ Shkolnik, Evgenya L. (2013), "An Ultraviolet Investigation of Activity on Exoplanet Host Stars", The Astrophysical Journal, 766 (1): 9, arXiv:1301.6192, Bibcode:2013ApJ...766....9S, doi:10.1088/0004-637X/766/1/9, S2CID 118415788
^ Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D. (2015), "Friends of Hot Jupiters III: An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal, 814 (2): 148, arXiv:1510.08062, Bibcode:2015ApJ...814..148P, doi:10.1088/0004-637X/814/2/148, S2CID 11525988
^ Wöllert, Maria; Brandner, Wolfgang (2015), "A Lucky Imaging search for stellar sources near 74 transit hosts", Astronomy & Astrophysics, 579: A129, arXiv:1506.05456, Bibcode:2015A&A...579A.129W, doi:10.1051/0004-6361/201526525, S2CID 118903879
^ ^a ^b "Украина выбрала имена для звезды и экзопланеты". LIGA.net. 18 December 2019. Retrieved 2019-12-18.
^ Van Laerhoven, Christa; Greenberg, Richard (2014), "Small Inner Companions of Warm Jupiters: Lifetimes and Legacies", The Astrophysical Journal, 778 (2): 182, arXiv:1401.7217, doi:10.1088/0004-637X/778/2/182, S2CID 119297266
^ Mancini, L.; et al. (2022), "The GAPS Programme at TNG", Astronomy & Astrophysics, 664: A162, arXiv:2205.10549, doi:10.1051/0004-6361/202243742, S2CID 248986121