WASP-49

WASP-49 is a binary star system about 636 ly away in the constellation Lepus. The two stars are separated by 443 AU. The primary is a G-type main-sequence star, with a surface temperature of 5600 K. WASP-49 is depleted of heavy elements relative to the Sun. It has a metallicity Fe/H index of –0.23, meaning it has 59% the iron level of the Sun.

Planetary system
In 2012, one exoplanet, designated WASP-49b, was discovered around the primary star by a team led by Monika Lendl. This is a hot Jupiter with an equilibrium temperature of $41.81$.

In 2017, WASP-49b was found to have an extensive sodium envelope. A study in 2019 using data from the Hubble Space Telescope in near-UV found clear absorption features caused by metals, including magnesium and iron. The magnesium and iron gas is not gravitationally bound to the planet, but could be magnetically confined to it. The sodium envelope around WASP-49b could be due to an Io-like exomoon. This idea, however, is speculative.