IOI
As part of the CARMENES radial velocity study, a multinational team of astronomers announced the discovery of two new Saturn-mass exoplanets. The newly discovered alien worlds TYC 2187-512-1 b and TZ Ari b orbit nearby M-dwarf stars and have been given the names TYC 2187-512-1 b and TZ Ari b. The results were presented in an article published on arXiv.org on March 30.
More than 600 exoplanets have been discovered so far using the radial velocity (RV) technique, with more than 100 of them orbiting M dwarfs. The Calar Alto high-resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs (CARMENES) project has played a critical role in the search for new extraterrestrial worlds orbiting our galaxy’s most frequent stars.
As part of the CARMENES study, a group of researchers led by Andreas Quirrenbach of Heidelberg University in Germany recently announced the finding of two more extrasolar worlds. Observations made with the 3.5 m telescope at the Calar Alto observatory in Almera, Spain, have verified the presence of huge planets in two neighbouring M dwarfs, TYC 2187-512-1 and TZ Ari.
“Here, we report on the discovery of two Saturn-mass planets from the CARMENES survey, which is currently carrying out precise radial-velocity observations of a sample of 387 M dwarfs,” the astronomers wrote in the paper.
TYC 2187-512-1 b orbits its host every 692 days in a near-circular orbit, at a distance of around 1.22 AU from the star, at a distance of 50.46 light years. The lowest mass of the planet was calculated to be 0.33 Jupiter masses. The parent star, TYC 2187-512-1, has a spectral class of M1.0 V and is approximately half the size and mass of our sun. The effective temperature of the device was determined to be 3,734 K.
The mass of TZ Ari b is at least 0.21 Jupiter masses. The orbital period of this planet is 771 days, and its orbital eccentricity is 0.46. According to the findings, the exoplanet is around 0.88 AU away from TZ Ari. The host star’s spectral type is M5.0 V, and its effective temperature is 3,154 K. This M dwarf is over six times smaller and has a fraction of the mass of the sun. The system is 14.57 light years away from us.
The properties of TZ Ari b, according to the authors of the article, distinguish it from other known huge exoworlds. It is just the second confirmed big planet orbiting a star with a mass less than 0.3 solar masses, according to the researchers.
“In fact, TZ Ari has a mass of 0.15 solar masses, which is identical to GJ 3512, another low-mass gas giant planet host. These two systems are in a region of the planet mass / host mass parameter space where disc fragmentation appears to be a more likely formation mechanism than planetesimal or pebble accretion to develop a core, ” according to the researchers.
The researchers stated in their concluding remarks that, based on their estimates, the occurrence rate of massive planets orbiting M dwarfs with periods up to two years should be in the range of 2 to 6%. They pointed out that once the CARMENES study is completed, this number would be more constrained.
