Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 02h 12m 31.4785s[1]
Declination +51° 46′ 43.5621″[1]
Apparent magnitude (V) 11.83
Evolutionary stage main-sequence star
Spectral type G
Radial velocity (Rv)-21.11[1] km/s
Proper motion (μ) RA: -9.805[1] mas/yr
Dec.: 1.898[1] mas/yr
Parallax (π)3.161 ± 0.0441[2] mas
Distance1,030 ± 10 ly
(316 ± 4 pc)
CompanionHAT-P-29 B
Semi-major axis (a)3.290±0.002"
(1041 AU)
Surface gravity (log g)4.337+0.045
Temperature6112±88 K
Metallicity [Fe/H]0.128+0.079
Age2.2±1.0[5] Gyr
Other designations
Muspelheim, HAT-P-29, Gaia DR2 359058441314838528, TYC 3293-1539-1, GSC 03293-01539, 2MASS J02123147+5146435[1]
Database references

HAT-P-29, also known as Muspelheim since 2019 (as part of the IAU's NameExoWorlds project),[6] is the primary of a binary star system about 1030 light-years 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.[5] HAT-P-29 is slightly enriched in heavy elements, having 35% more iron than the Sun.

The very faint 19-magnitude stellar companion was detected in 2016 at a projected separation of 3.290±0.002″.[3]

Planetary system

In 2011 a transiting hot Jupiter planet b was detected on a mildly eccentric orbit.[5] The planet was named "Surt" by Denmark in 2019.[7]

In 2018, a transit-timing variation survey indicated additional planets with masses exceeding approximately half of Earth are absent in the system.[4]

The HAT-P-29 planetary system[4]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b (Surt) 0.767+0.046
0.0665±0.0012 5.723376±0.000021 0.073+0.029


  1. ^ a b c d e f "HAT-P-29". SIMBAD. Centre de données astronomiques de Strasbourg.
  2. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. ^ a b Ngo, 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, S2CID 41083068
  4. ^ a b c Wang, Songhu; Wang, Xian-Yu; Wang, Yong-Hao; Liu, Hui-Gen; Hinse, Tobias C.; Eastman, Jason; Bayliss, Daniel; Hori, Yasunori; Hu, Shao-Ming; Li, Kai; Liu, Jinzhong; Narita, Norio; Peng, Xiyan; Wittenmyer, R. A.; Wu, Zhen-Yu; Zhang, Hui; Zhang, Xiaojia; Zhao, Haibin; Zhou, Ji-Lin; Zhou, George; Zhou, Xu; Laughlin, Gregory (2018), "Transiting Exoplanet Monitoring Project (TEMP). I. Refined System Parameters and Transit Timing Variations of HAT-P-29b", The Astronomical Journal, 156 (4): 181, arXiv:1807.10107, Bibcode:2018AJ....156..181W, doi:10.3847/1538-3881/aadcfc, S2CID 119415237
  5. ^ a b c Buchhave, 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, S2CID 119293967
  6. ^ IAU100 NameExoWorlds APPROVED NAMES
  7. ^ Denmark names new planet after Norse fire giant Surt

Coordinates: Sky map 02h 12m 31.4785s, +51° 46′ 43.5621″