WASP-50

WASP-50 is a G-type main-sequence star about 594 light-years away. The star is older than the Sun and slightly depleted in heavy elements compared to the Sun, and has a close to average starspot activity.^[5] Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by giant planet on close orbit.^[3]

WASP-50 / Chaophraya

Observation data Epoch J2000      Equinox J2000
Constellation	Eridanus
Right ascension	02h 54m 45.1342s[1]
Declination	−10° 53′ 53.025″[1]
Apparent magnitude (V)	11.44
Characteristics
Spectral type	G9V
Astrometry
Radial velocity (Rv)	25.24 km/s
Proper motion (μ)	RA: 3.383(20) mas/yr[1] Dec.: 8.913(17) mas/yr[1]
Parallax (π)	5.4865 ± 0.0174 mas[1]
Distance	594 ± 2 ly (182.3 ± 0.6 pc)
Details[2][3]
Mass	0.892+0.08 −0.074 M☉
Radius	0.843±0.031 R☉
Surface gravity (log g)	4.5±0.1 cgs
Temperature	5400±100 K
Metallicity	−0.12±0.08
Rotation	16.30 ± 0.50 d
Rotational velocity (v sin i)	2.6±0.5 km/s
Age	8.57±2.86 Gyr
Other designations
Gaia DR2 5160557726183065984, TYC 5290-462-1, GSC 05290-00462, 2MASS J02544513-1053530[4]
Database references
SIMBAD	data

The star was named Chaophraya in December 2019 by the Thai amateur astronomers.^[6]

Planetary system

In 2011 a transiting hot superjovian planet b (named Maeping in 2019^[6]) was detected.^[5] In 2022 its albedo was found to be no more than 0.44, meaning that the planet reflects less than 44% of the light irradiated by its host star. This allows the planetary equilibrium temperature to be constrained at 1393±42 K.^[7]

The WASP-50 planetary system^[2][5][8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b / Maeping	1.437±0.068 MJ	0.0293±0.0013	1.955100±0.000005	0.01+0.02 −0.01	84.88±0.27°	1.138±0.026 RJ

References

1. 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.
2. Chakrabarty, Aritra; Sengupta, Sujan (2019), "Precise Photometric Transit Follow-up Observations of Five Close-in Exoplanets: Update on Their Physical Properties", The Astronomical Journal, 158 (1): 39, arXiv:1905.11258, Bibcode:2019AJ....158...39C, doi:10.3847/1538-3881/ab24dd, S2CID 166227769
3. Maxted, P. F. L.; Serenelli, A. M.; Southworth, J. (2015), "A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars", Astronomy & Astrophysics, 577: A90, arXiv:1503.09111, Bibcode:2015A&A...577A..90M, doi:10.1051/0004-6361/201525774, S2CID 53324330
4. WASP-50 -- Star
5. Gillon, M.; Doyle, A. P.; Lendl, M.; Maxted, P. F. L.; Triaud, A. H. M. J.; Anderson, D. R.; Barros, S. C. C.; Bento, J.; Collier-Cameron, A.; Enoch, B.; Faedi, F.; Hellier, C.; Jehin, E.; Magain, P.; Montalban, J.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry, S.; West, R. G.; Wheatley, P. J. (2011), "WASP-50 b: a hot Jupiter transiting a moderately active solar-type star", Astronomy & Astrophysics, 533: A88, arXiv:1108.2641, Bibcode:2011A&A...533A..88G, doi:10.1051/0004-6361/201117198, S2CID 46639973
6. "Two celestial objects named Chao Phraya and Maeping". nationthailand.com. 19 December 2019. Retrieved 2020-07-30.
7. Blažek, Martin; Kabáth, Petr; Piette, Anjali A A; Madhusudhan, Nikku; Skarka, Marek; Šubjak, Ján; Anderson, David R; Boffin, Henri M J; Cáceres, Claudio C; Gibson, Neale P; Hoyer, Sergio; Ivanov, Valentin D; Rojo, Patricio M (2022-04-09). "Constraints on TESS albedos for five hot Jupiters". Monthly Notices of the Royal Astronomical Society. 513 (3): 3444–3457. doi:10.1093/mnras/stac992. ISSN 0035-8711.
8. Tregloan-Reed, Jeremy; Southworth, John (2012), "An extremely high photometric precision in ground-based observations of two transits in the WASP-50 planetary system", Monthly Notices of the Royal Astronomical Society, 431: 966–971, arXiv:1212.0686, doi:10.1093/mnras/stt227, S2CID 118869498