Looking for planets in cold stars
Small movements of the stars caused by the gravitational pull of the planets can provide evidence for exoplanets; It is a technique known as radial velocity. This method is based on the detection of small variations in the speed of a star due to the gravitational attraction of a planet in orbit around it, using spectroscopic observations. Recall that since the discovery in 1998 of the first radial velocity signal from an exoplanet around a cold star, A total of 116 exoplanets have been discovered around these types of stars and with this specific search method.
Evidence for this second planet, collected by measuring the star’s radial velocity, could be caused by the star’s magnetic field itself, not by a planet.
“The main difficulty of this method is related to the intense magnetic activity of this type of stars, which can produce spectroscopic signals very similar to those due to an exoplanet”, Explains Jonay I. González Hernández, IAC researcher.
The planet orbits its star with a period of 2.4 days and, because the star is so close to the Sun and the planet so close to the star, this new super Earth could be the subject of future research with large diameter telescopes as soon as towards the end of this decade. For the moment, more data is needed to confirm that the signal is actually due to that of a planet.
This detection was possible thanks to a six-year observation campaign with HARPS-N, from the HADES project, complemented with measurements with the CARMENES spectrograph at the 3.5 m telescope at the Calar Alto Observatory (Almería) and HARPS, at the 3.6 m telescope at the La Silla Observatory (Chile), among other instruments.