There has been a fully comprehensive study of red dwarf stars to find exoplanets in orbit around them in recent years. These stars have masses between 0.08 and 0.45 solar masses and effective surface temperatures between 2400 and 3700 K. A team of researchers led by Borja Toledo Padrón, a Severo Ochoa-La Caixa doctoral student at IAC specializing in searching planets around this type of stars. They have discovered a super-Earth orbiting a red dwarf star GJ 740, situated some 36 light-years from the Earth.
With a period of 2.4 days, the planet orbits its star, and its mass is around three times the mass of the Earth. The star is very close to the sun, and the planet is so closed to the star; towards the end of the decade, with giant diameter telescopes, this new super-Earth could be the object of future researches. In the journal Astronomy & Astrophysics, the results of the study were recently published.
As per Borja Toledo Padrón, “This is the planet with the second shortest orbital period around this type of star. The mass and the period suggest a rocky planet, with a radius of around 1.4 Earth radii, which could be confirmed in future observations with the TESS satellite.” The data also indicate the presence of the 2nd planet with a mass comparable to Saturn and with an orbital period of 9 years. But its radial velocity signal could be due to the magnetic cycle of the star, so more data is needed to be gathered to confirm that the signal is due to the planet.
The Kepler mission has discovered a total of 156 new planets around cool stars. This mission is one of the successful missions in detecting exoplanets using the transit method. The data collected in this mission estimates that this type of star has orbital periods of less than 200 days with 2.5 planets. According to Borja Toledo Padrón, the search for new exoplanets around cool stars is driven by the minor difference between the star’s mass and the planet’s mass compared with stars in warmer spectral classes, as well as a large number of this type of star in our Galaxy.