HAT-P-7

Last updated
HAT-P-7
Observation data
Epoch J2000       Equinox J2000
Constellation Cygnus [1]
Right ascension 19h 28m 59.3539s [2]
Declination +47° 58′ 10.217″ [2]
Apparent magnitude  (V)10.46 [3]
Characteristics
A
Evolutionary stage Main sequence [4]
Spectral type F6V [5]
Apparent magnitude  (B)~10.90 [3]
Apparent magnitude  (V)~10.46 [3]
Apparent magnitude  (J)9.555 ± 0.030 [3]
Apparent magnitude  (H)9.344 ± 0.029 [3]
Apparent magnitude  (K)9.334 ± 0.018 [3]
Variable type planetary transit [6]
B
Evolutionary stage Main sequence [7]
Spectral type M5.5V [8]
Astrometry
Radial velocity (Rv)−10.23±0.25 [2] km/s
Proper motion (μ)RA: −18.325(14) mas/yr [2]
Dec.: 8.851(14) mas/yr [2]
Parallax (π)2.9991±0.0114  mas [2]
Distance 1,088 ± 4  ly
(333 ± 1  pc)
Orbit [7]
PrimaryA
CompanionB
Semi-major axis (a)730 AU
Orbit [7]
PrimaryA
CompanionC
Semi-major axis (a)32+16
−11 AU
Eccentricity (e)0.76+0.12
−0.26
Details
A
Mass 1.35±0.22 [4]   M☉
Radius 1.994±0.081 [4]   R☉
Surface gravity (log g)3.97±0.08 [4]   cgs
Temperature 6,532±109 [4]   K
Metallicity [Fe/H]0.15±0.08 [9]   dex
Rotational velocity (v sin i)5.0±1.2 [9]  km/s
B
Mass 0.21 [7]   M☉
C
Mass 0.19 [7]   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 [3]
Database references
SIMBAD data
Exoplanet Archive data

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. [3]

Contents

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. [7]

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, [8] but its nature was unknown until 2025, when it was found to be a third star. [7]

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. [10] [8]

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 [6] and was given the designation KOI-2 and later Kepler-2.

The HAT-P-7 planetary system [11]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 1.806±0.036  MJ 0.03813±0.000362.20473539167(1654) [12] <0.004083.151+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

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