Discovery of a super-Earth ideal for testing planetary atmospheric models

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March 4th 2021

An international team of astronomers has discovered a hot super-Earth around the Gliese 486 star, only 26 light-years away from our Sun. This exoplanet, detected by the CARMENES instrument at the Calar Alto observatory 3.5 meter telescope, might be the Rosetta Stone for the study of the atmospheres of rocky planets.

During the last quarter of century, astronomers have discovered an ample variety of exoplanets made of rock, ice or gas. The commissioning of new astronomical instruments, like the CARMENES spectrograph at Calar Alto Observatory (Almeria, Spain), specialized in planet hunting, has allowed us to detect several thousands of new worlds out of the Solar System. Among all of them, only a handful are similar to our Earth, like the Teegarden b exoplanet found at Calar Alto.

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Star formation in gravitationally perturbed galaxies

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December 31st 2020

An international team has studied the rates of star formation in galaxies from the CALIFA survey and has found subtle differences between galaxies influenced by neighbors, and those unperturbed. Gravitational interaction between galaxies could enhance the star formation in the inner regions of perturbed ones.

Galaxies are huge assemblies of billions of stars as well as tons of dust and gas. Stars were and are born from this gas, when it collapses by gravitation into “big balls of plasma”, so hot that nuclear reactions of fusion start in their cores. Then, stars live for millions to billions of years in a pretty stable state, converting hydrogen into helium -- and more complex atoms -- while releasing their heat and light, like our Sun does. Stars eventually die, in more or less violent explosions, rejecting their “recycled” material (richer in complex chemical elements) back to their host galaxy. New generations of stars can then be formed from this richer gas and dust.

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When Jupiter meets Saturn with the Schmidt telescope

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December 28th 2020

On the 2020 winter solstice, Jupiter passed Saturn in a great conjunction in dusk. This apparent (line-of-sight only) encounter, easily visible to the naked eye as a bright “double star” in the evening sky, was caught with the smallest of the four main telescopes in Calar Alto: the 1-meter class Schmidt telescope.

This historical telescope (Großer Hamburger Schmidtspiegel) represents the culmination of the know-how of Bernhard Schmidt, a German optician who proposed, in 1930, a brand new and revolutionary concept for a wide-field but nearly perfect quality optics telescope.  Despite the construction of a “great Schmidt”, of about one meter in diameter, was planned to start in 1937 inside the famous Carl Zeiss factory in Jena, World War II delayed its final commissioning to 1951.

Initially installed at Hamburg university observatory, near the village of Bergedorf, this site soon appeared to be hardly usable for serious astronomical research, due to the poor weather and growing light pollution in the Hamburg countryside. In the late 1970s, astronomers from Hamburg and MPIA Heidelberg thus decided to move the precious optical tube to Calar Alto; in 1980, the great Schmidt was commissioned again with a new, English made mount adapted to the lower Andalusian latitude of its new observatory.

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Habitable moons around cool nearby stars: from science fiction to reality

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December 14th 2020

CARMENES is an instrument designed to find small planets around cool dwarf stars, but it could also detect large satellites that is, moons, of exoplanets. Some of these exomoons may harbor seas of liquid water, favorable places for the development of life.

In Avatar’s universe, Pandora is the fifth moon of Polyphemus, a fictional giant planet around the nearby star Alpha Centauri A; in the Alien saga, Ellen Ripley fought xenomorphs in an infested colony on Acheron, one of the moons of Calpamos, another made-up planet around the real star zeta2 Reticuli; a long time ago, in a galaxy far, far away the Rebel Alliance defeated the Galactic Empire in space battles in orbit of Yavin IV first and, finally, Endor, which were also habitable moons. But do habitable extrasolar moons, or exomoons, exist in reality? And how are they related to Calar Alto?

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