L 98-59
L 98-59 is a bright M dwarf star, located in the constellation of Volans, at a distance of, as measured by the Gaia spacecraft.
Broadband photometry shows that it is an M3 dwarf star with three confirmed terrestrial-sized planets in transit, which were announced in March 2019 by TESS, as well as two additional non-transiting planets, for a total of five known planets. The outermost planet is in the habitable zone.
Planetary system
The planets b, c, and d of L 98-59 were discovered in 2019 by TESS. The potential super-Venus planet L 98-59 e was discovered in 2021, along with potentially habitable super-Earth L 98-59 f. In September 2021, suggested tests of the abilities of the Hubble Space Telescope and the James Webb Space Telescope to detect and describe the atmospheric features of the three inner planets were reported. Planet f was confirmed in 2025, along with the detection of an additional planet candidate.The two innermost confirmed planets, L 98-59 b and c, as well as L 98-59 e are possibly hot rocky worlds. L 98-59 d has a low density, indicating large amounts of water, potentially making up as much as 30% of its entire mass. It may therefore be covered in a deep global ocean. Hubble observations of the three transiting planets in 2022 have found no clear evidence of atmospheres, with high mean molecular weight atmospheres, cloudy or hazy atmospheres, or no atmospheres all being consistent with the observed flat spectra. One study found some evidence of an atmosphere on L 98-59 c, which has yet to be confirmed as of 2023. Transmission spectroscopy by the JWST suggest that L 98-59 d might have a atmosphere rich in sulfur-compounds.