HAT-P-7

HAT-P-7
Observation data
Epoch J2000      Equinox ICRS
Constellation Cygnus
Right ascension 19h 28m 59.3539s
Declination +47° 58′ 10.217″
Apparent magnitude (V) 10.46
Characteristics
A
Evolutionary stage Main sequence
Spectral type F6V
Apparent magnitude (B) ~10.90
Apparent magnitude (V) ~10.46
Apparent magnitude (J) 9.555 ± 0.030
Apparent magnitude (H) 9.344 ± 0.029
Apparent magnitude (K) 9.334 ± 0.018
Variable type planetary transit
B
Evolutionary stage Main sequence
Spectral type M5.5V
Astrometry
Radial velocity (Rv)−10.23±0.25 km/s
Proper motion (μ) RA: −18.325(14) mas/yr
Dec.: 8.851(14) mas/yr
Parallax (π)2.9991±0.0114 mas
Distance1,088 ± 4 ly
(333 ± 1 pc)
Orbit
PrimaryA
SecondaryB
Semi-major axis (a)730 AU
Orbit
PrimaryA
SecondaryC
Semi-major axis (a)32+16
−11 AU
Eccentricity (e)0.76+0.12
−0.26
Details
A
Mass1.35±0.22 M☉
Radius1.994±0.081 R☉
Surface gravity (log g)3.97±0.08 cgs
Temperature6,532±109 K
Metallicity [Fe/H]0.15±0.08 dex
Rotational velocity (v sin i)5.0±1.2 km/s
B
Mass0.21 M☉
C
Mass0.19 M☉
Other designations
HAT-P-7, BD+47°2846, Kepler-2, KOI-2, KIC 10666592, TOI-1265, TIC 424865156, TYC 3547-1402-1, GSC 03547-01402, 2MASS J19285935+4758102
Database references
SIMBADdata
Exoplanet Archivedata

HAT-P-7 is a triple star system located about 1,088 light-years away in the constellation Cygnus. The apparent magnitude of this star is 10.5, which means it is not visible to the naked eye but can be seen with a small telescope on a clear dark night.

Stellar system

The primary component of the HAT-P-7 system is an F-type main-sequence star with around 1.35 times the Sun's mass and twice the Sun's radius, hosting one known planet. The secondary is a red dwarf located 730 astronomical units away from the primary, with a spectral type of M5.5V and a mass of 0.21 M☉. The tertiary is also a red dwarf with a mass of at least 0.15 M☉; it is in a highly-eccentric orbit with a semi-major axis of 32 AU.

The secondary star, component B, was discovered in 2012. Another companion (in addition to the second star and the planet) was suspected based on long-period radial velocity variations, but its nature was unknown until 2025, when it was found to be a third star.

Component B has also been referred to as HAT-P-7 East. HAT-P-7 West is another candidate companion, of spectral type M9V or L0V, but it is not confirmed to be associated with the system and is likely an unrelated background star.

Planetary system

The primary star has one known planet, HAT-P-7b, a hot Jupiter discovered in 2008. This star system was within the initial field of view of the Kepler planet-hunting spacecraft and was given the designation KOI-2 and later Kepler-2.

The HAT-P-7 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination
(°)		 Radius
b 1.806±0.036 MJ 0.03813±0.00036 2.20473539167(1654) <0.0040 83.151+0.030
−0.033		 1.51±0.02 RJ

See also

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 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.
  3. 1 2 3 4 5 6 7 8 "HAT-P-7". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-29.
  4. 1 2 3 4 5 Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay; Rojas-Ayala, Bárbara; Fleming, Scott W.; Rose, Mark E.; Tenenbaum, Peter; Ting, Eric B. (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256.
  5. ↑ Faedi, F.; et al. (2013). "Lucky imaging of transiting planet host stars with LuckyCam". Monthly Notices of the Royal Astronomical Society. 433 (3): 2097–2106. arXiv:1305.3795. Bibcode:2013MNRAS.433.2097F. doi:10.1093/mnras/stt885.
  6. 1 2 Pál, A.; et al. (2008). "HAT-P-7b: An Extremely Hot Massive Planet Transiting a Bright Star in the Kepler Field". The Astrophysical Journal. 680 (2): 1450–1456. arXiv:0803.0746. Bibcode:2008ApJ...680.1450P. doi:10.1086/588010.
  7. 1 2 3 4 5 6 7 Yang, Eritas; Su, Yubo; Winn, Joshua N. (2025-05-12). "A third star in the HAT-P-7 system, and a new dynamical pathway to misaligned hot Jupiters". The Astrophysical Journal. 986 (2): 117. arXiv:2505.07927. Bibcode:2025ApJ...986..117Y. doi:10.3847/1538-4357/add5f7.
  8. 1 2 3 Narita, Norio; Takahashi, Yasuhiro H.; et al. (December 2012). "A Common Proper Motion Stellar Companion to HAT-P-7". Publications of the Astronomical Society of Japan. 64 (6): L7. arXiv:1209.4422. Bibcode:2012PASJ...64L...7N. doi:10.1093/pasj/64.6.L7.
  9. 1 2 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.
  10. ↑ Narita, Norio; et al. (2010). "Search for Outer Massive Bodies around Transiting Planetary Systems: Candidates of Faint Stellar Companions around HAT-P-7". Publications of the Astronomical Society of Japan. 62 (3): 779. arXiv:1004.2458. Bibcode:2010PASJ...62..779N. doi:10.1093/pasj/62.3.779.
  11. ↑ 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.
  12. ↑ Battley, Matthew P; et al. (10 March 2021). "Revisiting the Kepler field with TESS: Improved ephemerides using TESS 2 min data". Monthly Notices of the Royal Astronomical Society. 503 (3): 4092–4104. arXiv:2103.03259. Bibcode:2021MNRAS.503.4092B. doi:10.1093/mnras/stab701.

Further reading