HAT-P-7
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]
Stellar system
[edit]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
[edit]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.
| 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)[12] | <0.0040 | 83.151+0.030 −0.033° |
1.51±0.02 RJ |
See also
[edit]References
[edit]- ^ 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.
- ^ a b c d e 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.
- ^ a b c d e f g h "HAT-P-7". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-29.
- ^ a b c d e 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.
- ^ 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.
- ^ a b 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.
- ^ a b c d e f g 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". arXiv:2505.07927.
- ^ a b c 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.
- ^ a b 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.
- ^ 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.
- ^ 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.
- ^ 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
[edit]- Morris, Brett M.; et al. (2013). "Kepler's Optical Secondary Eclipse of HAT-P-7b and Probable Detection of Planet-induced Stellar Gravity Darkening". The Astrophysical Journal Letters. 764 (2). L22. arXiv:1301.4503. Bibcode:2013ApJ...764L..22M. doi:10.1088/2041-8205/764/2/L22.
- Rhodes, Michael D.; Puskullu, Caglar; Budding, Edwin; Banks, Timothy S. (2020). "Exoplanet System Kepler-2 with comparisons to Kepler-1 and 13". Astrophysics and Space Science. 365 (4): 77. arXiv:2004.07971. Bibcode:2020Ap&SS.365...77R. doi:10.1007/s10509-020-03789-3. S2CID 215814387.
External links
[edit]- "HAT-P-7". Exoplanets. Archived from the original on 2016-03-03. Retrieved 2009-05-03.