HAT-P-8

HAT-P-8

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Pegasus
Right ascension	22^h 52^m 09.8636^s[1]
Declination	+35° 26′ 49.608″[1]
Apparent magnitude (V)	10.17[2]
Characteristics
Spectral type	F[3]
Apparent magnitude (B)	10.77 ± 0.04[2]
Apparent magnitude (V)	10.36 ± 0.03[2]
Apparent magnitude (J)	9.214 ± 0.022[2]
Apparent magnitude (H)	9.004 ± 0.018[2]
Apparent magnitude (K)	8.953 ± 0.013[2]
Variable type	planetary transit[3]
Astrometry
Radial velocity (Rv)	−22.2±0.3[1] km/s
Proper motion (μ)	RA: 74.676(19) mas/yr[1] Dec.: 14.944(20) mas/yr[1]
Parallax (π)	4.6606 ± 0.0208 mas[1]
Distance	700 ± 3 ly (214.6 ± 1.0 pc)
Details
Mass	1.27±0.03[4] M☉
Radius	1.491^+0.016 −0.014[4] R☉
Surface gravity (log g)	4.1956^+0.0095 −0.013[4] cgs
Temperature	6410±140[4] K
Metallicity [Fe/H]	-0.018^+0.0072 −0.056[4] dex
Rotational velocity (v sin i)	12.6 ± 1.0[5] km/s
Age	3.4 ± 1 Gyr
Other designations
Gaia DR3 1891507552826485632, TYC 2757-1152-1, GSC 02757-01152, 2MASS J22520985+3526495[2]
Database references
SIMBAD	data

HAT-P-8 is a magnitude 10 star located 700 light-years away in Pegasus.^[2] It is a F-type star about 28% more massive than the Sun.^[3] Two red dwarf companions have been detected around HAT-P-8. The first has a spectral type of M5V and has a mass of 0.22 M_☉. The second is even less massive, at 0.18 M_☉, and its spectral type is M6V.^[6]

Planetary system

In 2008 the HATNet Project announced the discovery of extrasolar planet HAT-P-8b around this star. This planet is a hot Jupiter gas giant planet.^[3]

The HAT-P-8 planetary system^[7]^[8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	1.354±0.035 MJ	0.04496+0.00046 −0.00045	3.0763458±0.0000024	<0.0060	—	1.334±0.013[4] RJ

See also

• HATNet Project
• List of extrasolar planets

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
2. "HAT-P-8". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2009-04-24.
3. Latham, David W.; et al. (2009). "Discovery of a Transiting Planet and Eight Eclipsing Binaries in HATNet Field G205". The Astrophysical Journal. 704 (2): 1107–1119. arXiv:0812.1161. Bibcode:2009ApJ...704.1107L. doi:10.1088/0004-637X/704/2/1107. S2CID 120615043.
4. Wang, Xian-Yu; et al. (1 July 2021). "Transiting Exoplanet Monitoring Project (TEMP). VI. The Homogeneous Refinement of System Parameters for 39 Transiting Hot Jupiters with 127 New Light Curves". The Astrophysical Journal Supplement Series. 255 (1). 15. arXiv:2105.14851. Bibcode:2021ApJS..255...15W. doi:10.3847/1538-4365/ac0835. S2CID 235253975.
5. Torres, Guillermo; et al. (2012). "Improved Spectroscopic Parameters for Transiting Planet Hosts". The Astrophysical Journal. 757 (2). 161. arXiv:1208.1268. Bibcode:2012ApJ...757..161T. doi:10.1088/0004-637X/757/2/161. S2CID 16580774.
6. Bechter, Eric B.; et al. (2014). "WASP-12b and HAT-P-8b are Members of Triple Star Systems". The Astrophysical Journal. 788 (1). 2. arXiv:1307.6857. Bibcode:2014ApJ...788....2B. doi:10.1088/0004-637X/788/1/2. S2CID 36306243.
7. Mancini, L.; et al. (2013). "A lower radius and mass for the transiting extrasolar planet HAT-P-8 b". Astronomy and Astrophysics. 551. A11. arXiv:1212.3701. Bibcode:2013A&A...551A..11M. doi:10.1051/0004-6361/201220291. S2CID 118498705.
8. Bonomo, A. S.; et al. (2017). "The GAPS Programme with HARPS-N at TNG . XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy and Astrophysics. 602. A107. arXiv:1704.00373. Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882. S2CID 118923163.

External links

• [1] Star : HAT-P-8b