WASP-21


WASP-21 is a G-type star that is reaching the end of its main sequence lifetime approximately 850 light years from Earth in the constellation of Pegasus that 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.
The survey in 2012 have 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.

Planetary System

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