The planets were found as part of the CARMENES radial velocity study. The results of the study are published on the preprint site arXiv.org.
An international team of astronomers announces the discovery of two new exoplanets with the mass of Saturn. The newly discovered alien worlds have been designated TYC 2187-512-1 b and TZ Ari b. Both planets orbit nearby M-dwarfs.
Scientists conducted observations using a 3.5-meter telescope at the Calar Alto Observatory in Almería, Spain. They confirmed that two nearby M-dwarfs were orbited by massive planets.
TYC 2187-512-1 b is 50.46 light-years from Earth. The planet revolves around the host star every 692 days in a nearly circular orbit at a distance of about 1.22 AU. from a star. The minimum mass of the planet is estimated at 0.33 Jupiter masses. The parent star TYC 2187-512-1 belongs to the spectral type M1.0 V, its size and mass is half that of the Sun. The effective temperature is 3,734 Kelvin (3,460.85 °C).
The mass of TZ Ari b is less than 0.21 Jupiter masses. The orbital period of this planet is 771 days. The results show that the exoplanet is about 0.88 AU distant. from the host star. Its spectral type is M5.0 V and its effective temperature is 3,154 K (2,880.85 °C). This M-dwarf is six times smaller and more massive than the Sun. The system is located at a distance of about 14.57 light years from Earth.
The authors of the article emphasize that the parameters of TZ Arib b make it a unique planet among other known giant exoworlds. It just shouldn’t exist, it’s just the second confirmed giant planet orbiting a star with a mass less than 0.3 solar masses.