Scientists have discovered a new ‘super Earth’ planet with a mass around 5.4 times that of the Earth, orbiting a very bright star near to our Sun. The exoplanet, GJ 536 b, is not within the star’s habitable zone, but its short orbital period of 8.7 days and the luminosity of its star make it an attractive candidate for investigating its atmospheric composition, researchers said. The star, GJ 536, is a red dwarf which is quite cool and near to our Sun, they said.
During the research, a cycle of magnetic activity similar to that of the Sun has been observed, but with a shorter period, three years. “So far, the only planet we have found is GJ 536 b, but we are continuing to monitor the star to see if we can find other companions,” said Alejandro Suarez Mascareno from the Instituto de Astrofisica de Canarias (IAC) and the University of La Laguna (ULL) in Spain.
“Rocky planets are usually found in groups, especially around stars of this type, and we are pretty sure that we can find other low-mass planets in orbits further from the star, with periods from 100 days up to a few years,” Mascareno said. “We are preparing a programme of monitoring for transits of this new exoplanet to determine its radius and mean density,” he said.
“This rocky exoplanet is orbiting a star much smaller and cooler than the Sun. But it is sufficiently nearby and bright,” said researcher Jonay Isai Gonzalez. “It is also observable from both the northern and southern hemispheres, which is very interesting for future high-stability spectrographs, and in particular, for the possible detection of another rocky planet in the habitability zone of the star,” said Gonzalez.
To detect the planet, the researchers had to measure the velocity of the star with an accuracy of the order of a metre per second. The planet was detected in a joint effort between the IAC and the Geneva Observatory, using the HARPS (High Accuracy Radial velocity Planet Seeker) spectrograph on the 3.6M ESO Telescope at La Silla in Chile and HARPS North, on the Telescopio Nacional Galileo (TNG) at the Roque de los Muchachos Observatory, Garafia in Spain. The finding appears in the journal Astronomy and Astrophysics.