Astronomers Detect a New Super-Earth Orbiting a Red Dwarf Star

Artistic impression of the super-Earth in orbit around the red dwarf star GJ-740. Credit: Gabriel Pérez Díaz, SMM (IAC)

In recent years there has been an exhaustive study of red dwarf stars to find exoplanets in orbit around them. These stars have effective surface temperatures between 2400 and 3700 K (over 2000 degrees cooler than the Sun), and masses between 0.08 and 0.45 solar masses. In this context, a team of researchers led by Borja Toledo Padrón, a Severo Ochoa-La Caixa doctoral student at the Instituto de Astrofísica de Canarias (IAC), specializing in the search for planets around this type of stars, has discovered a super-Earth orbiting the star GJ 740, a red dwarf star situated some 36 light years from the Earth.

The planet orbits its star with a period of 2.4 days and its mass is around 3 times the mass of the Earth. Because the star is so close to the Sun, and the planet so close to the star, this new super-Earth could be the object of future researches with very large diameter telescopes towards the end of this decade. The results of the study were recently published in the journal Astronomy & Astrophysics.

“This is the planet with the second shortest orbital period around this type of star. The mass and the period suggest a rocky planet, with a radius of around 1.4 Earth radii, which could be confirmed in future observations with the TESS satellite,” explains Borja Toledo Padrón, the first author of the article. The data also indicate the presence of a second planet with an orbital period of 9 years, and a mass comparable to that of Saturn (close to 100 Earth masses), although its radial velocity signal could be due to the magnetic cycle of the star (similar to that of the Sun), so that more data are needed to confirm that the signal is really due to a planet.

The Kepler mission, recognized at one of the most successful in detecting exoplanets using the transit method (which is the search for small variations in the brightness of a star caused by the transit between it and ourselves of planets orbiting around it), has discovered a total of 156 new planets around cool stars. From its data, it has been estimated that this type of star harbors an average of 2.5 planets with orbital periods 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,” comments Borja Toledo Padrón.

Cool stars are also an ideal target for the search for planets via the radial velocity method. This method is based on the detection of small variations in the velocity of a star due to the gravitational attraction of a planet in orbit around it, using spectroscopic observations. Since the discovery in 1998 of the first radial velocity signal of an exoplanet around a cool star, until now, a total of 116 exoplanets has been discovered around this class of stars using the radial velocity method. “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,” says Jonay I. González Hernández, an IAC researcher who is a co-author of this 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 study is part of the project HADES (HArps-n red Dwarf Exoplanet Survey), in which the IAC is collaborating with the Institut de Ciències de l’Espai (IEEC-CSIC) of Catalonia, and the Italian program GAPS (Global Architecture of Planetary Systems), whose objective is the detection and characterization of exoplanets round cool stars, in which are being used 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 six year observing campaign with HARPS-N, complemented 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), as well as photometric support from the ASAP and EXORAP surveys. Also participating in this work are IAC researchers Alejandro Suárez Mascareño, and Rafael Rebolo.

AstronomyAstrophysicsExoplanetInstituto De Astrofísica De CanariasPopular
Comments ( 11 )
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  • mike lermontov

    36 light years? that’s only an hour or so at warp 7.

  • JimB

    You said “ Because the star is so close to the Sun, and the planet so close to the star, this new super-Earth could be the object of future researches with very large diameter telescopes towards the end of this decade.”
    I don’t understand. I thought the sun was the star. What’s the deal with a Star, Sun and planet?? Please help me understand. I thought I was pretty good with astronomy.

  • Alex

    Sounds like we found Superman’s home plant, aka Krypton… Anyone else think it, am I right?

  • Me

    I think us Humans as we call ourselves are the future in other words we been existing for unumbered yrs we came to this world we destroyed marsin the way way way past future

  • Me

    And Kno as we know earth is in danger and we looking for another place to live the reason is that technology if we don’t understand it we live longer there should only exist technology for science only to better the worlds around us n this where we live and we shoUld live

  • Lee Lewis

    That’s just round the corner. It’s 36 light years so that’s about 6 day’s to get there if we travel at 150 miles per hour. Lol 😂

  • Turbo

    With all these new planets we are discovering, I don’t see any of them being populated in the future.

    • Adrian Scott Herbert

      Yes, there’s only been 50 Earth-like planets identified within habitable zones lol. And that number precludes gas giants with large Earth-like planets within their atmospheres.

  • TOM

    @Jim B
    They are explaining to us, that this star is so close to our sun we should think about it as a destination; Apparently 36 years traveling at the speed of light is close.

  • TOM

    @JimB.
    Clearly you werent paying attention during your schooling.
    Sun = the name of our star
    Star = generic name of bright hot large ass burning object in space

  • Chris Wheeler

    Wevhumans are ignorant!!! That’s all