WASP-21

WASP-21, also named Tangra, is a G-type star that has reached the end of its main sequence lifetime. It lies approximately 834 light-years away, in the constellation of Pegasus. The star is relatively metal-poor, having 40% of heavy elements compared to the Sun. Kinematically, WASP-21 belongs to the thick disk of the Milky Way. It has an exoplanet named WASP-21b.
A survey in 2012 failed to find any stellar companions to WASP-21.

Naming

In 2019 the WASP-21 system was chosen as part of the NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. WASP-21 was assigned to Bulgaria. The winning proposal named the star Tangra after a deity worshipped by the early Bulgars, and the planet Bendida after a deity worshipped by the Thracians.

In 2010 WASP-21 was discovered to host a hot Jupiter type planet by the Wide Angle Search for Planets, confirmed by radial velocity by the WASP team in 2010.
Transit-timing variation analysis in 2015 did not find any additional planets in the system.
In 2020, spectroscopic analysis found that the WASP-21b atmosphere is mostly cloudless and contains sodium.