L 168-9
L 168-9 is a red dwarf star located away from the Solar System in the constellation of Tucana. The star has about 61% the mass and 60% the radius of the Sun. It has a temperature of and a rotation period of 29 days. L 168-9 is orbited by one known exoplanet.
Nomenclature
The designation L 168-9 comes from Luyten's first catalogue of stars with high proper motion.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 China, were announced in June 2023. L 168-9 is named Danfeng and its planet is named Qingluan, after mythological birds of ancient China.
Planetary system
The exoplanet L 168-9 b, officially named Qingluan, was discovered in 2020 using TESS. At the discovery, this terrestrial super-Earth was thought to have about 4.6 times the mass and 1.39 times the radius of Earth, and an estimated equilibrium temperature of. L 168-9 b is a target for observation and atmospheric characterization with the James Webb Space Telescope, and has been observed as one of its first targets.A newer study refined the planetary parameters of L 168-9 b. The newer research found a lower mass of and a higher radius of. These parameters imply a lower density of, in contrast to the previous value of. Given the lower density of the planet, it more likely has a pure rock composition, rather than a 50% iron core and 50% silicate mantle as previously proposed. The orbital parameters show little variation, while the equilibrium temperature was updated to.
Transmission spectra of combined near- and mid-infrared observations by the James Webb Space Telescope showed no atmospheric features. However, further observations are required to rule out a thick carbon dioxide atmosphere, which could also explain the data.