An international collaboration of researchers has discovered two new super-Earths orbiting around a bright red dwarf star located 33 light years away.
Both objects are among the closest rocky planets known to date outside the solar system.
These two new exoplanets, HD 260655 b and HD 260655 c, have been detected with the help of the US agency NASA’s Transiting Exoplanet Survey Satellite (TESS), a space telescope designed to search for planets in orbit around nearby bright stars using the method of transit.
This system measures the decrease in brightness of a star when the planet crosses the stellar disk seen from the telescope, explains in a statement the Institute of Astrophysics of the Spanish archipelago of the Canary Islands (IAC), which participates in the study,
The research, whose results are presented this Wednesday at the meeting of the American Astronomical Society (AAS) in Pasadena (California, United States), has determined that both planets are super-earths, that is, planets like Earth, but larger.
Planet b is about 1.2 times as big as Earth and planet c is 1.5 times as big.
However, it is unlikely that either world could support life. The temperature of planet b, the closest to the star, is estimated at 435 degrees Celsius, and that of c, at 284 degrees.
At 33 light-years away, the discovered exoplanets are relatively close together, in what is called the solar neighborhood, and their red dwarf star, although smaller than the Sun, is one of the brightest of its kind.
This makes the two planets ideal candidates for investigating their atmospheres.
According to the study, both planets are among the top ten candidates for atmospheric characterization among all terrestrial exoplanets discovered to date.
“This places them in the same category as one of the most famous planetary systems: the seven planets similar in size to Earth that surround the TRAPPIST-1 star,” explains Spaniard Rafael Luque, who led the study.
These and other rocky exoplanets are already on the list of observing targets for the James Webb Space Telescope, which will soon show scientific images.
This telescope will be able to capture data on starlight through the atmospheres of these planets.
Said light can be broken down into its different frequencies (spectrum) and reveal the “fingerprints” of the molecules within the atmosphere itself, being able to detect water, carbon and other essential components for life, the IAC sources detail.
To confirm the existence of the two new planets, in addition to the observations made by TESS, the scientific team has also used ground-based instrumentation, such as the CARMENES spectrographs from the Calar Alto Observatory (Almería, southeastern Spain) and HIRES from the WM Keck observatory ( Mauna Kea, Hawaii).
These instruments have made it possible to measure the “wobble” of the star caused by the gravitational pulls of the orbiting planets (radial velocity), which yields information about their masses. Combining these measurements, it has also been possible to determine the density and confirm that they are rocky worlds.
Although it is still unknown whether either of the two super-Earths has an atmosphere and, if so, what it is made of, the combined data from the different observational studies suggest that the planets do not have dense hydrogen atmospheres.
But for the scientific team it is just an interesting clue that encourages further investigation.
“Learning more about the atmospheres of rocky planets will help scientists understand the formation and development of worlds like ours,” concludes Luque.