HAT-P-5

HAT-P-5 is a 12th magnitude star in the constellation Lyra, approximately 1,000 light years away from Earth. It is a spectral type G star, about 1.16 solar masses and radii greater than the Sun, and only 200 kelvins hotter. It is estimated to be 2.6 billion years old.^[7][8]

HAT-P-5

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lyra[1]
Right ascension	18h 17m 37.3127s[2]
Declination	+36° 37′ 17.170″[2]
Apparent magnitude (V)	+11.95
Characteristics
Spectral type	G1V
Variable type	planetary transit[3]
Astrometry
Radial velocity (Rv)	8.56±1.11[2] km/s
Proper motion (μ)	RA: 11.925(11) mas/yr[2] Dec.: 5.904(14) mas/yr[2]
Parallax (π)	3.2184±0.0105 mas[2]
Distance	1,013 ± 3 ly (311 ± 1 pc)
Details
Mass	1.157+0.043 −0.081[4] M☉
Radius	1.165+0.046 −0.052[4] R☉
Surface gravity (log g)	4.37 ± 0.03[5] cgs
Temperature	5863 ± 80[5] K
Metallicity [Fe/H]	0.10 ± 0.10[5] dex
Rotational velocity (v sin i)	2.8 ± 1.0[5] km/s
Age	2.6+2.1 −1.4[4] Gyr
Other designations
Chasoň, TOI-2135, TIC 76419763, TYC 2634-1087-1, GSC 02634-01087, 2MASS J18173731+3637170, HAT-P-5[6]
Database references
SIMBAD	data
Exoplanet Archive	data

The star HAT-P-5 is named Chasoň. The name was selected in the NameExoWorlds campaign by Slovakia, during the 100th anniversary of the IAU. Chasoň is an ancient Slovak term for the Sun.^[9][10]

Planetary system

On October 9, 2007, a report was submitted to The Astrophysical Journal Letters telling of the discovery of an exoplanet transiting HAT-P-5. The planet was described as a Jupiter-like hot Jupiter, with a radius about one and one quarter times that of Jupiter, and nearly the same mass. Its density was reported as 0.66 ± 0.11 g/cm³, and its inclination 86.75 ± 0.44°.^[3]

The HAT-P-5 planetary system^[4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b / Kráľomoc	1.02±0.10 MJ	0.04073+0.00050 −0.00093	2.78847360(52)	<0.072	86.75±0.44°	1.204±0.017[11] RJ

See also

• HAT-P-4
• HAT-P-6
• List of extrasolar planets