Two new exoplanets detected by Complutense University’s Stellar Astrophysics Group
June 16, 2022

With the help of NASA’s Transiting Exoplanet Survey Satellite (TESS) space telescope, the Complutense University Stellar Astrophysics Group has detected two new exoplanets, HD 260655 b and HD 260655 c.

Research has determined that both planets are “super-Earths,” meaning like our own, but larger. Planet b is about 1.2 times as large as Earth, and planet c is 1.5 times as big as Earth. In this case, however, planet b, where neither world is closest to the star, has an estimated temperature of 435 °C and planet c at 284 °C.

At 33 light-years from Earth, their red dwarf is the brightest of its kind, though smaller than the Sun. This makes the two sister planets prime candidates for atmospheric research. Of all the Earth-like exoplanets discovered so far, planet b is among the top 10 candidates for atmospheric signatures; planet c is in the top five, according to the study. “They belong to the same category as one of the most famous planetary systems: seven Earth-sized planets orbiting the star TRAPPIST-1.”

These and other rocky exoplanets are already on the watch list of the James Webb Space Telescope (JWST), which will soon provide its first scientific images. The telescope will be able to capture data from starlight passing through the atmospheres of these planets. This light can diffuse across the spectrum and reveal molecular fingerprints of the atmosphere itself, enabling the detection of water, carbon and other components necessary for life. In addition to the TESS observations, the scientists used data from other ground-based telescopes using the HIRES (Keck Telescope, Mauna Kea) and CARMENES (3.5 m Telescope, Caral Alto, Almeria) spectrographs to Confirm the existence of both new planets. With this information about the planet’s mass, it is possible to determine the density and confirm that they are rocky worlds.

While it is unclear whether the two super-Earths have an atmosphere, and if so, what it is made of, combined data from different observational studies suggest that the atmospheres of the two planets do not have hydrogen expansion.

The project was led by an international team of astronomers led by researcher Rafael Luque of the Andalusian Institute of Astrophysics (IAA-CSIC) and the University of Chicago, with the participation of the Complutense University Stellar Astrophysics Group led by researcher David Montes. The discovery has been accepted for publication in the scientific journal Astronomy & Astrophysics, and the results were presented at the AAS (American Astronomical Society) meeting in Pasadena on June 15, 2022.