HAT-P-21 is a G-type main sequence star about 910 light-years away. The star has an amount of metals similar to solar abundance. The 2015 survey has not been able to detect any stellar companions. The star rotates rapidly, being driven by the tides of the giant planet in close orbit.

In 2019, the star HAT-P-21 was given the proper name Mazalaai while its planet HAT-P-21b was given the name Bambaruush in an international NameExoWorlds competition. These names refer to the Mongolian name of the endangered Gobi bear subspecies and the Mongolian term for “bear cub”, respectively.

In 2010, a hot super Jovian planet was detected in transit in a moderately eccentric orbit. Its equilibrium temperature is 1283±50 K. The 2011 transit time variation study has not been able to rule out or confirm the existence of additional planets in the system, until the orbital parameters of HAT-P-21b are more accurately known.


Comments of HAT-P-21b

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