The designation WASP-63 indicates that this was the 63rd star found to have a planet by the Wide Angle Search for Planets. It is also known as CD-38 2551 from the Durchmusterung catalog.[8]
In the 2019 NameExoWorlds campaign, this system was assigned to Malawi[9][10] but did not get named at that time. It was then included among 20 systems to be named by the following NameExoWorlds campaign in August 2022.[11] The approved names, proposed by a team from Croatia, were announced in June 2023. WASP-63 is named Kosjenka and its planet is named Regoč, after characters from Croatian Tales of Long Ago by Ivana Brlić-Mažuranić.[12]
Stellar properties
This is a G-type star with a stellar classification of G8;[4] the luminosity class is currently unknown. The star is much older than the Sun at approximately 8.3+1.3 −1.2 billion years. WASP-63 is slightly enriched in heavy elements, having 120% of the solar abundance of iron.[6] The stellar radius is enlarged for a G8 star,[4] and models suggest it has evolved into a subgiant star.[2] It has 1.1 times the mass of the Sun and is spinning with a projected rotational velocity of 3 km/s.[6]
Planetary system
In 2012 a transitinggas giant planet WASP-63b was detected on a tight, circular orbit.[4] Its equilibrium temperature is 1536±37 K, and measured dayside temperature is 1547±308 K.[13] The planet is similar to Saturn in mass but is highly inflated due to proximity to the parent star. The planetary atmosphere contains water and likely has a high cloud deck of indeterminate composition.[14]
