HAT-P-21
Coordinates: 
11h 25m 05.9858s, +41° 01′ 40.6692″
11h 25m 05.9858s, +41° 01′ 40.6692″| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 11h 25m 05.9859s[1] |
| Declination | +41° 01′ 40.665″[1] |
| Apparent magnitude (V) | 11.46[2] |
| Characteristics | |
| Spectral type | G3V |
| Details Gyr | |
| Database references | |
| SIMBAD | data |
HAT-P-21 is a G-type main-sequence star about 927 light-years away. The star has amount of metals similar to solar abundance. The survey in 2015 has failed to detect any stellar companions.[6] The star is rotating rapidly, being spun up by the tides of giant planet on close orbit.[4]
Naming
In 2019, the HAT-P-21 star received the proper name Mazalaai while its planet
HAT-P-21b received the name Bambaruush at an international NameExoWorlds contest.[7] These names refer to the Mongolian name for the endangered Gobi bear
subspecies, and the Mongolian term for 'bear cub', respectively.
Planetary system
In 2010 a
HAT-P-21b are known with better precision.[5]
The planetary orbit is likely aligned with the equatorial plane of the star, misalignment equal to 25±16 degrees.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
b (Bambaruush)
|
4.063±0.161 MJ | 0.0494±0.0007 | 4.124481±0.000007 | 0.228±0.016 | 88.6° | 1.08±0.18 RJ |
References
- ^ S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b HAT-P-21 -- Star
- S2CID 119219062
- ^ S2CID 53324330
- ^ S2CID 118460941
- S2CID 119250579
- ^ "IAU 100 NameExoWorlds Approved Names". Archived from the original on 2019-12-19. Retrieved 2020-07-08.
- ^ S2CID 119182075
- S2CID 248986121
- S2CID 202931761
