HAT-P-29, also known as Muspelheim since 2019 (as part of the IAU's NameExoWorlds project),[6] is a star about 1,040 light-years (320 parsecs) away. It is a G-type main-sequence star. The star's age of 2.2±1.0 billion years is less than half that of the Sun.[4] HAT-P-29 is slightly enriched in heavy elements, having 35% more iron than the Sun.
A very faint 19th-magnitude stellar companion was detected in 2016 at a projected separation of 3.290±0.002″,[2] but Gaia DR2 astrometry suggests that this is an unrelated background object.[7]
Planetary system
In 2011 a transitinghot Jupiter planet, HAT-P-29b, was detected on a mildly eccentric orbit.[4] The planet was named "Surt" by Denmark in 2019.[8] The planetary orbit is likely aligned with the equatorial plane of the star, with a misalignment equal to 26±16 degrees.[9]
In 2018, a transit-timing variation survey indicated additional planets with masses exceeding approximately half of Earth are absent in the system.[3]
^ abNgo, Henry; Knutson, Heather A.; Hinkley, Sasha; Bryan, Marta; Crepp, Justin R.; Batygin, Konstantin; Crossfield, Ian; Hansen, Brad; Howard, Andrew W.; Johnson, John A.; Mawet, Dimitri; Morton, Timothy D.; Muirhead, Philip S.; Wang, Ji (2016), "FRIENDS OF HOT JUPITERS. IV. STELLAR COMPANIONS BEYOND 50 au MIGHT FACILITATE GIANT PLANET FORMATION, BUT MOST ARE UNLIKELY TO CAUSE KOZAI–LIDOV MIGRATION", The Astrophysical Journal, 827 (1): 8, arXiv:1606.07102, Bibcode:2016ApJ...827....8N, doi:10.3847/0004-637X/827/1/8, S2CID41083068
^ abcBuchhave, L. A.; Bakos, G. Á.; Hartman, J. D.; Torres, G.; Latham, D. W.; Andersen, J.; Kovács, G.; Noyes, R. W.; Shporer, A.; Esquerdo, G. A.; Fischer, D. A.; Johnson, J. A.; Marcy, G. W.; Howard, A. W.; Béky, B.; Sasselov, D. D.; Fűrész, G.; Quinn, S. N.; Stefanik, R. P.; Szklenár, T.; Berlind, P.; Calkins, M. L.; Lázár, J.; Papp, I.; Sári, P. (2011), "HAT-P-28b AND HAT-P-29b: TWO SUB-JUPITER MASS TRANSITING PLANETS", The Astrophysical Journal, 733 (2): 116, arXiv:1103.1813, Bibcode:2011ApJ...733..116B, doi:10.1088/0004-637X/733/2/116, S2CID119293967
