Artistic impression of the very-Earth in orbit around the red dwarf star GJ-740. Credit: Gabriel Pérez Díaz, SMM (IAC)
In current years there has actually been an extensive research study of red dwarf stars to discover exoplanets in orbit around them. These stars have reliable surface area temperature levels in between 2400 and 3700 K (over 2000 degrees cooler than the Sun), and masses in between 0.08 and 0.45 solar masses. In this context, a group of scientists led by Borja Toledo Padrón, a Severo Ochoa-La Caixa doctoral trainee at the Instituto de Astrofísica de Canarias (IAC), concentrating on the look for worlds around this kind of stars, has actually found a very-Earth orbiting the star GJ 740, a red dwarf star positioned some 36 light years from the Earth.
The world orbits its star with a duration of 2.4 days and its mass is around 3 times the mass of the Earth. Because the star is so near to the Sun, and the world so near to the star, this brand-new very-Earth might be the things of future investigates with large size telescopes towards completion of this years. The outcomes of the research study were just recently released in the journal Astronomy & Astrophysics.
“This is the world with the 2nd quickest orbital duration around this kind of star. The mass and the duration recommend a rocky world, with a radius of around 1.4 Earth radii, which might be verified in future observations with the TESS satellite,” discusses Borja Toledo Padrón, the very first author of the short article. The information likewise show the existence of a 2nd world with an orbital duration of 9 years, and a mass equivalent to that of Saturn (near to 100 Earth masses), although its radial speed signal might be due to the magnetic cycle of the star (comparable to that of the Sun), so that more information are required to verify that the signal is actually due to a world.
The Kepler objective, acknowledged at one of the most effective in discovering exoplanets utilizing the transit technique (which is the look for little variations in the brightness of a star brought on by the transit in between it and ourselves of worlds orbiting around it), has actually found an overall of 156 brand-new worlds around cool stars. From its information, it has actually been approximated that this kind of star harbors approximately 2.5 worlds with orbital durations of less than 200 days. “The search for new exoplanets around cool stars is driven by the smaller difference between the planet’s mass and the star’s mass compared with stars in warmer spectral classes (which facilitates the detection of the planets’ signals), as well as the large number of this type of star in our Galaxy,” remarks Borja Toledo Padrón.
Cool stars are likewise a perfect target for the look for worlds by means of the radial speed technique. This technique is based upon the detection of little variations in the speed of a star due to the gravitational destination of a world in orbit around it, utilizing spectroscopic observations. Since the discovery in 1998 of the very first radial speed signal of an exoplanet around a cool star, previously, an overall of 116 exoplanets has actually been found around this class of stars utilizing the radial speed technique. “The main difficulty of this method is related to the intense magnetic activity of this type of stars, which can produce spectroscopic signals very similar to those due to an exoplanet,” states Jonay I. González Hernández, an IAC scientist who is a co-author of this short article.
Reference: “A super-Earth on a close-in orbit around the M1V star GJ 740: A HADES and CARMENES collaboration” by B. Toledo-Padrón, A. Suárez Mascareño, J. I. González Hernández, R. Rebolo,, M. Pinamonti, M. Perger, G. Scandariato, M. Damasso, A. Sozzetti, J. Maldonado, S. Desidera, I. Ribas, G. Micela, L. Affer, E. González-Alvarez, G. Leto, I. Pagano, R. Zanmar Sánchez, P. Giacobbe, E. Herrero, J. C. Morales, P. J. Amado, J. A. Caballero, A. Quirrenbach, A. Reiners and M. Zechmeister, 7 April 2021, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202040099
The research study belongs to the task HADES (HArps-n red Dwarf Exoplanet Survey), in which the IAC is teaming up with the Institut de Ciències de l’Espai (IEEC-CSIC) of Catalonia, and the Italian program SPACES (Global Architecture of Planetary Systems), whose goal is the detection and characterization of exoplanets round cool stars, in which are being utilized HARPS-N, on the Telescopio Nazionale Galileo (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma). This detection was possible due to a 6 year observing project with HARPS-N, matched with measurements with the CARMENES spectrograph on the 3.5m telescope at the Calar Alto Observatory (Almería) and HARPS, on the 3.6m telescope at the La Silla Observatory (Chile), in addition to photometric assistance from the ASAP and EXORAP studies. Also taking part in this work are IAC scientists Alejandro Suárez Mascareño, and Rafael Rebolo.
