HAT-P-65

HAT-P-65 is a faint star located in the equatorial constellation Equuleus. With an apparent magnitude of 13.16, it requires a telescope to be seen. The star is located 2,460 light-years (750 pc) away from Earth,^[2] but is drifting close with a radial velocity of -48 km/s.

HAT-P-65

Observation data Epoch J2000      Equinox J2000
Constellation	Equuleus[1]
Right ascension	21h 03m 37.3131s[2]
Declination	+11° 59′ 21.820″[2]
Apparent magnitude (V)	13.16±0.02[3]
Characteristics
Spectral type	G2IV[4]
B−V color index	+0.65[3]
Astrometry
Radial velocity (Rv)	−47.77±0.10[4] km/s
Proper motion (μ)	RA: 4.175(24) mas/yr[2] Dec.: −6.263(16) mas/yr[2]
Parallax (π)	1.3261±0.0353 mas[2]
Distance	2,460 ± 70 ly (750 ± 20 pc)
Details[5]
Mass	1.297+0.056 −0.053 M☉
Radius	1.666(24) R☉
Luminosity	2.97(12) L☉
Surface gravity (log g)	4.1079+0.068 −0.074 cgs
Temperature	5872(40) K
Metallicity [Fe/H]	0.208+0.050 −0.055 dex
Rotational velocity (v sin i)	7.1±0.5[4] km/s
Age	3.9(8) Gyr
Other designations
Gaia DR3 1757302881526250496, GSC 01111-00383, 2MASS J21033731+1159218[6]
Database references
SIMBAD	data
Exoplanet Archive	data

Properties

HAT-P-65 has a similar spectral type to that of the Sun. However, it is 21% more massive, and 86% larger than the latter. HAT-P-65 is slightly hotter, with an effective temperature of 5,916 K compared to 5,778 K of the Sun. It also has a higher luminosity and metallicity, with an iron content 26% greater than the Sun.

Planetary system

In 2016, an inflated hot Jupiter was discovered orbiting the star in a tight 2 day orbit.^[4] No significant transit timing variations or evidence of orbital decay was found in a 2024 study by Kang et. al.^[5]

The HAT-P-65 planetary system^[5]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.554+0.092 −0.091 MJ	0.04042+0.00057 −0.00055	2.60544751(50)	0 (assumed)	88.3(1.0)°	1.611(24) RJ