A team of researchers from the Université de Montréal and Trottier Institute for Research on Exoplanets has confirmed a fifth potentially habitable planet around L 98-59, a red dwarf star located 35 light-years away. The discovery was made using a combination of data from space-based telescopes and high-precision instruments.
The study found that four planets in the system are small and rocky, with masses and sizes compatible with terrestrial regimes. One of these planets, L 98-59 b, is a sub-Earth with a size similar to Earth’s but half its mass. The other two inner planets may experience extreme volcanic activity due to tidal heating.
A fifth planet, designated L 98-59 f, was confirmed using radial velocity measurements from HARPS and ESPRESSO spectrographs. This planet receives about the same amount of stellar energy as Earth does from the sun, placing it firmly within the habitable zone, where water could remain in liquid form.
The team used a novel line-by-line radial velocity analysis technique to improve the precision of the data significantly. By combining this with analysis of transits seen by the James Webb Space Telescope (JWST), they were able to precisely identify and remove the stellar activity signal from the data, revealing the planetary signal in unprecedented detail.
The discovery highlights the diversity of exoplanetary systems and strengthens the case for studying potentially habitable worlds around low-mass stars. L 98-59 joins a select group of nearby compact planetary systems that are being studied in greater detail using the JWST.
Source: https://phys.org/news/2025-07-team-potentially-habitable-planet-red.html