WASP-69

WASP-69, also named Wouri, is a K-type main-sequence star 164 light-years (50 parsecs) away from Earth in the constellation Aquarius. Its surface temperature is 4782±15 K. WASP-69 is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.10±0.01, and is much younger than the Sun at 2 billion years. The data regarding starspot activity of WASP-69 are inconclusive, but spot coverage of the photosphere may be very high.

Multiplicity surveys did not detect any stellar companions to WASP-69 as of 2020.

Nomenclature

The designation WASP-69 indicates that this was the 69th star found to have a planet by the Wide Angle Search for Planets.

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project. The approved names, proposed by a team from Cameroon, were announced in June 2023. WASP-69 is named Wouri and its planet is named Makombé, after the Wouri and Makombé rivers in Cameroon.

Planetary system

In 2013, one planet, named WASP-69b, was discovered on a tight, circular orbit. Its equilibrium temperature is 886 K, but the measured terminator temperature is significantly higher by at least 200 K. The planet is losing mass at a moderate rate of 0.5 M_🜨 per billion years, producing a tail detected in 2024 and measured to be at least 7 times its own radius.

The planetary atmosphere is extremely hazy and contains a partial cloud deck with cloud tops rising to a pressure of 100 Pa. Its composition is mostly hydrogen and helium, and sodium was also detected in low concentration. The sodium may originate from volcanic moons, not from the planet itself.

By 2021, the presence of hazes in atmosphere of WASP-69b was confirmed, along with a solar or super-solar water abundance.