So far, scientists have identified two planets, Gliese 887b and Gliese 887c, each averaging temperatures between 200 and 80 degrees Celsius. “We found two worlds orbiting one of the closest stars to Earth, which is just over 10 light-years away. These have a minimum mass of between 4 and 8 times that of our planet ”, details Doctor James Jenkins, astronomer of the Astronomy Department of the Faculty of Physical and Mathematical Sciences of the University of Chile.
The team, led by Dr. Sandra Jeffers of the University of Göttingen (Germany), observed the star GJ 887 for three months thanks to the High Accuracy Radial Velocity Planet Searcher (HARPS), a high-precision spectrograph dedicated to searching for planets. , located at ESO’s La Silla Observatory (Chile).
Detection was performed using the method called Doppler spectroscopy or radial velocities. This method measures the “wobble” of the star due to the gravitational influence of the planets that orbit it. Archival observations spanning more than twenty years are included in the data.
The two planets fall into the category of super-Earths, that is, with a mass greater than that of our planet but substantially less than Neptune.
A third guest
“We know that these types of planetary systems are quite common in other stars – between 15 and 30% of solar-type stars – but we had not found any so close to the Sun,” says Guillem Anglada-Escudé, another of the authors of the research and member of the Institute of Space Sciences (ICE-CSIC in Spain).
“The star of this System is so bright, that we can be sure that later we will be able to study the heat distribution of its atmospheres, that is something remarkable. Additionally we find the sign of what a third planet would be, if we get to confirm it the good news is that it would be located in what we call the ‘habitable zone’, that is, it would be in an area that has a temperature that is not nearly as neither hot nor cold, which makes possible the existence of liquid water on its surface ”, indicates James Jenkins, who is also a researcher at the CATA Center of Excellence in Astrophysics and Related Technologies.
“For the study, data from 4 different instruments were used, of which 2 are installed in Chile. Our group contributed data that complemented that obtained by the RedDots # 2 campaign. For the analysis of more than 20 years of data, a set of statistical and computational tools were used that included a code developed in our group, which allowed confirming the results and ruling out possible scenarios due to the star’s activity, “explains Matías Díaz, PhD student in sciences mentioning astronomy FCFM of the University of Chile and one of the authors of the paper.
“GJ887 is one of the 12 closest stars to the Sun, to continue on this path we will be adding a new grain of sand in our permanent search to find life outside of planet Earth”, concludes Díaz
To confirm the existence of this third planet around GJ 887, some more data is needed, scientists believe that these could be obtained in a couple of more observation campaigns.
Original note published in Science Magazine in https://science.sciencemag.org/content/368/6498/1477
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