Two new super-Earths discovered near Earth

The researchers report in a study accepted in the journal. astronomy and astrophysics, discovery by space telescope tess of two La question des exoplanètes est très ancienne dans l’astronomie. Leur existence est pour la première fois attestée de façon indirecte dans…” data-image=”” data-url=”” data-more=”Lire la suite”>exoplanets strangely similar to Earth. Called HD 260655b and HD 260655c, these two super-Earths orbit around one étoile woman red, HD 260655, 33 light-years away. A distance that makes this system “the fourth closest known multiplanetary system after HD 219134, LTT 1445 A and AU Mic”details the study.

Two new uninhabitable super-Earths

the space telescope tess (Transiting Exoplanet Survey Satellite) of NASA applies from 2018 to detect exoplanets associated with the bright stars closest to us. To do this, it uses the method of transits: it consists of pointing at a star for a period of time sufficient to observe variations in brightness periodic, due to the passage of a planet in front of its host star. Using this, scientists can track the diameter of the planet, using the intensity of the dip in brightness, and the size of its star.

In the case of the red dwarf HD 260655, much smaller than the Le Soleil est l’étoile la plus proche de la Terre, dont elle est distante d’environ 150 millions de kilomètres. Le Soleil est situé à 8,5 kparsecs du centre de la Voie lactée. Dans la classification des étoiles, le soleil est une étoile de type G2.
La masse…” data-image=”” data-url=”” data-more=”Lire la suite”>Sun
but nonetheless bright enough, the researchers also determined its dough Thanks to the radial velocity method. It allows us to deduce the gravitational influence that is exerted on the star, observing periodic variations in its luminous spectrum: when the radial velocity of the star changes, the lines ofPHYSIOLOGIE Pénétration d’une substance venant de l’extérieur dans un organisme vivant. Absorption intestinale : passage des substances nutritives de…” data-url=”” data-more=”Lire la suite”>absorption change. “Every planet in orbit around a star is going to have a small gravitational pull on its star.explains Michelle Kunimoto, postdoctoral researcher at MIT (Massachusetts Institute of Technology) and who participated in the discovery of the two exoplanets. “What we are looking for is very light movement of this star which could indicate that a planetary-mass object is shooting at it. »

From these data, it is possible to deduce the mass that causes this influence, therefore, the mass of the exoplanet. Combined with the diameter, the researchers deduced the density of the two exoplanets: being similar to that of Earth, they most likely correspond to rocky planetslike mercure, Venusearth and Mars. With a mass and size close to that of Earth, this makes them super-Earths. However, they are uninhabitable: with tight orbits close to their star, the temperatures calculated by scientists reach 435 °C for HD 260655b and 284 °C for HD 260655c. “We consider this beach to be outside the habitable zone, too warm for any warm water. liquid exists on the surfaceby M Kunimoto

Ideal candidates for an atmospheric study

But hope is not lost for the HD 260655 system: the researchers estimate that it could host more than two exoplanets. “There could be more planets in the system”adds Avi Shporer, co-discoverer of these two rocky worlds and a researcher at MIT. “There are many multiplanetary systems that host five or six planets, especially around small stars like this one. Hopefully we’ll find more, and maybe we’ll be in the habitable zone. It is an optimistic thought. »

Very soon they could be the target of the James–Webb Telescopewhich will present its first images on July 12. Because of its proximity and the luminosity of its star, “The two planets of this system are considered among the best targets for atmospheric study”explains Mr. Kunimoto. For now, the team has determined that if they have a atmosphereIt is not extensive and consists mainly ofGénéralités
Symbole : H Numéro atomique :…” data-image=”” data-url=”” data-more=”Lire la suite”>hydrogen
. Being similar in density and size to Earth, the team hopes to learn more about its formation through them.

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