HAT-P-29

HAT-P-29, also known as Muspelheim since 2019 (as part of the IAU's NameExoWorlds project),^[7] is a star about 1,040 light-years (320 parsecs) away. It is an F-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.

HAT-P-29 / Muspelheim

Observation data Epoch J2000      Equinox J2000
Constellation	Perseus[1]
Right ascension	02h 12m 31.47875s[2]
Declination	+51° 46′ 43.5637″[2]
Apparent magnitude (V)	11.83[3]
Characteristics
Evolutionary stage	main-sequence[2][4]
Spectral type	F8[4]
Astrometry
Radial velocity (Rv)	−21.91±0.69[2] km/s
Proper motion (μ)	RA: −9.972 mas/yr[2] Dec.: +1.790 mas/yr[2]
Parallax (π)	3.1358±0.0201 mas[2]
Distance	1,040 ± 7 ly (319 ± 2 pc)
Absolute magnitude (MV)	+4.11[4]
Details[5]
Mass	1.198+0.065 −0.063 M☉
Radius	1.229+0.080 −0.073 R☉
Luminosity	1.89+0.3 −0.25 L☉
Surface gravity (log g)	4.337+0.045 −0.045 cgs
Temperature	6,112±88 K
Metallicity [Fe/H]	0.128+0.079 −0.080 dex
Age	2.2±1.0[4] Gyr
Other designations
Muspelheim, TYC 3293-1539-1, GSC 03293-01539, 2MASS J02123147+5146435[6]
Database references
SIMBAD	data
Exoplanet Archive	data

A very faint 19th-magnitude stellar companion was detected in 2016 at a projected separation of 3.290±0.002″,^[8] but Gaia DR2 astrometry suggests that this is an unrelated background object.^[9]

Planetary system

In 2011 a transiting hot Jupiter planet, HAT-P-29b, was detected on a mildly eccentric orbit.^[4] The planet was named "Surt" by Denmark in 2019.^[10] The planetary orbit is likely aligned with the equatorial plane of the star, with a misalignment equal to 26±16 degrees.^[11]

The HAT-P-29 planetary system^[5]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b (Surt)	0.767+0.046 −0.045 MJ	0.0665±0.0012	5.723376±0.000021	0.073+0.029 −0.028	88.06+0.78 −0.59°	1.055+0.079 −0.072 RJ