A new super-land has fallen into the exoplanet hunting nets. Gliese 411b is only 8 light years away from the Sun, which bodes well for the analysis of the atmosphere it may have.
The Observatoire de Haute-Provence (OHP), which, as its name suggests, is located in the Alpes-de-Haute-Provence, was for decades the most important observatory in Europe before ESO finally its now famous telescopes in Chile. Located at Saint-Michel-l’Observatoire, near Forcalquier and Manosque, its pre-eminence was largely due to the 1.93 m diameter telescope which saw its first light in 1958, but also because the observations there are possible for a very large number of nights throughout the year.
The 1.93 m telescope is still there. It became particularly famous in 1995, and thanks to the spectrograph Elodie, a discovery of the first exoplanet in orbit around a star on the famous main sequence was made. It is the use of the radial velocity method that has allowed this success that, without any doubt, has brought the OHP into the history of Humanity.
Today, the large 1.93 m telescope still contributes to the hunt for exoplanets, especially since it was equipped with an even more powerful spectrograph in 2006: Sophie. We have a new proof of this with the announcement of the discovery by an international team of astronomers of the third exoplanet closest to our solar system. It is a super-earth located about 8 light-years from the Solar System and is orbiting a red dwarf in the constellation Ursa Major, numbered 411 in the famous Gliese-Jahreiss catalog. This catalog, named after astronomers Wilhelm Gliese and Hartmut Jahreiss, attempts to list all the stars located within 25 parsecs of the Sun.
Gl 411b: a target for the next generation of telescopes
Among the astronomers responsible for the discovery of the Gl 411b exoplanet is Xavier Delfosse, a researcher at the Institute of Planetology and Astrophysics of Grenoble (Ipag, University Grenoble-Alpes / CNRS), who had granted an interview to Futura at subject of discoveries of superterre in the Milky Way. He recalls in the CNRS press release, accompanying the publication of an article in Astronomy & Astrophysics available for free access on arXiv, about Gl 411b the following: “Direct observations to characterize terrestrial-type extraterrestrial planets will only be possible in the coming years if the target is one of the closest exoplanets to us. It is therefore crucial today to discover our closest neighbors.” This is especially necessary if we are to be able to analyze relatively pushing the composition of the atmosphere of potentially habitable planets in search of biosignatures.
But let’s do a little digging into Gl 411b. Its mass is estimated to be about three times that of the Earth and it winds its orbit in about 13 days at only 0.08 AU, which in the Solar System would place it at a distance five times closer to its star than Mercury does. But since Gl 411 is a red dwarf with a colder surface temperature (3.300 ° C, compared to 5.500 ° C for the Sun), Gl 411b receives only 3.5 times more energy than the Earth receives. This remains considerable so that it is not in the livability zone and if it has an atmosphere, which remains to be demonstrated, Gl 411b should rather resemble the infernal world of Venus.