ADS 16402

ADS 16402 is a binary star system, composed of two sun-like stars located approximately 525 light-years away in the constellation Lacerta. It was first identified as a binary star by John Herschel in 1831.^[5] The two stars are separated by 11.26 arcseconds which leads to a projected separation of roughly 1500 astronomical units at the distance of ADS 16402. The star system is estimated to be 1.9 ± 0.6 billion years old.^[8] The secondary star ADS 16402 B is also designated HAT-P-1.

ADS 16402

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lacerta[1]
ADS 16402 A
Right ascension	22h 57m 45.9211s[2]
Declination	+38° 40′ 27.200″[2]
Apparent magnitude (V)	+10.0[3]
ADS 16402 B (HAT-P-1)
Right ascension	22h 57m 46.8442s[4]
Declination	+38° 40′ 30.358″[4]
Apparent magnitude (V)	+10.4[3]
Characteristics
ADS 16402 A
Spectral type	F8[3]/G0V[5]
Apparent magnitude (J)	8.670±0.021[6]
Apparent magnitude (H)	8.467±0.044[6]
Apparent magnitude (K)	8.405±0.020[6]
ADS 16402 B (HAT-P-1)
Spectral type	F8[3]/G0V[5]
Apparent magnitude (J)	9.156±0.026[6]
Apparent magnitude (H)	8.923±0.030[6]
Apparent magnitude (K)	8.858±0.018[6]
Variable type	planetary transit[5]
Astrometry
ADS 16402 A
Radial velocity (Rv)	−3.43 ± 0.32[5] km/s
Proper motion (μ)	RA: 32.079(15) mas/yr[2] Dec.: −42.076(18) mas/yr[2]
Parallax (π)	6.2364±0.0164 mas[2]
Distance	523 ± 1 ly (160.3 ± 0.4 pc)
Absolute magnitude (MV)	3.4 ± 0.3[5]
ADS 16402 B (HAT-P-1)
Radial velocity (Rv)	−2.94 ± 0.56[5] km/s
Proper motion (μ)	RA: 32.422(14) mas/yr[4] Dec.: −41.949(13) mas/yr[4]
Parallax (π)	6.2438±0.0146 mas[4]
Distance	522 ± 1 ly (160.2 ± 0.4 pc)
Absolute magnitude (MV)	3.7 ± 0.3[5]
Details
ADS 16402 A
Mass	1.16 ± 0.11[5] M☉
Radius	1.123 +0.14 −0.10[5] R☉
Luminosity	1.82 +0.75 −0.53[5] L☉
Surface gravity (log g)	4.36 ± 0.03[7] cgs
Temperature	6251 ± 17[7] K
Metallicity [Fe/H]	0.146 ± 0.014[7] dex
Rotational velocity (v sin i)	7.1 ± 0.3[5] km/s
Age	1.9 ± 0.6[8] Gyr
ADS 16402 B (HAT-P-1)
Mass	1.151 +0.052 −0.051[9] M☉
Radius	1.174 +0.026 −0.027[9] R☉
Luminosity	1.585 +0.099 −0.094[9] L☉
Surface gravity (log g)	4.43 ± 0.02[7] cgs
Temperature	6049 ± 8[7] K
Metallicity [Fe/H]	0.155 ± 0.007[7] dex
Rotational velocity (v sin i)	2.2 ± 0.2[5] km/s
Age	1.9 ± 0.6[8] Gyr
Position (relative to ADS 16402 A)
Angular distance	11.26 ± 0.03″ [10]
Other designations
BD+37°4734, CCDM J22578+3840, WDS J22578+3840, HJ 1832[11][12]
ADS 16402 A: Gaia DR3 1928431764627661312, PPM 88381, 2MASS J22574592+3840272[11]
ADS 16402 B: HAT-P-1, Gaia DR3 1928431764627661440, PPM 88382, 2MASS J22574684+3840302[12]
Database references
SIMBAD	ADS 16402
	ADS 16402 A
	HAT-P-1

Planetary system

On September 14, 2006 the HATNet Project announced their first extrasolar planet discovery HAT-P-1b, a hot jupiter type gas giant in orbit around the secondary star ADS 16402B. Following the designation scheme used by the HATNet Project, the secondary star is known as HAT-P-1, and the planet itself designated HAT-P-1b.^[5][13]

The HAT-P-1 planetary system^[14][9]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.529 ± 0.020 MJ	0.05561 ± 0.00083	4.4652968 ± 0.0000018	0	85.634 ± 0.056°	1.319 ± 0.019 RJ

See also

• HATNet Project or HAT