An international team of astronomers has discovered a super-Earth planet in orbit around Gliese 536, a red dwarf star approximately 33 light-years away.
An artist’s concept of Gliese 536b orbiting its star, 33 light-years from Earth. Image credit: Gabriel Perez / Instituto de Astrofísica de Canarias.
Gliese 536, also known as GJ 536 and HD 122303, is a high proper-motion M1-type star of about half the mass of the Sun.
The star’s low activity combined with its long rotation period of 45 days makes it a very promising candidate to search for terrestrial planets.
The newfound planet, Gliese 536b (or GJ 536b), is about 5.4 times as massive as the Earth.
It has an orbital period of 8.7 days and is about 0.067 AU (astronomical units) from the parent star — much closer than our planet is to the Sun.
“So far the only planet we have found is Gliese 536b, but we are continuing to monitor the star to see if we can find other companions,” said team member Alejandro Suarez Mascareno, from the Instituto de Astrofísica de Canarias and the University of La Laguna, Spain.
“Rocky planets are usually found in groups, especially around stars of this type, and we are pretty sure that we can find other super-Earths in orbits further from the star, with periods from 100 days up to a few years.”
According to Suarez Mascareno and co-authors, Gliese 536b is too close to its star to be considered habitable.
Based on the planet’s distance from the star, they estimate that the planet’s temperature ranges between 158 and 417 degrees Fahrenheit (70 – 214 degrees Celsius).
“For Gliese 536 the orbital periods of the habitable zone would be from 20 days to 40 days,” they explained.
Gliese 536b was detected using the HARPS spectrograph on the 3.6-m telescope at ESO’s La Silla Observatory in Chile and the HARPS-North instrument on the Telescopio Nacional Galileo at the Roque de los Muchachos Observatory in the Canary Islands.
“This rocky exoplanet is orbiting a star much smaller and cooler than the Sun, but sufficiently nearby and bright,” said team member Dr. Jonay Gonzalez Hernandez, also from the Instituto de Astrofísica de Canarias and the University of La Laguna.
“It is also observable from both the northern and southern hemispheres, so that it is a very interesting for future high stability spectrographs and, in particular, for the possible detection of another rocky planet in the habitable zone of the star.”
The discovery is reported in the journal Astronomy & Astrophysics (arXiv.org preprint).
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A. Suarez Mascareno et al. A super-Earth orbiting the nearby M dwarf GJ 536. A&A, published online November 17, 2016; doi: 10.1051/0004-6361/201629291
