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Artist’s impression of two super earths around the red dwarf star Gliese 887 (illustration).
Copyright: Mark Garlick
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Göttingen (Germany) – Around the sun-like star “Gliese 887” astronomers have discovered a system of super-earth planets that orbit their star on the edge of its “habitable zone” and thus orbit within the distance region within which a planet orbits its star must, so that due to mild temperatures liquid water – and thus the basis of at least earthly life – can exist.
As the team around Dr. Sandra Jeffers from the University of Göttingen currently in the specialist journal “Sciecne” (DOI: 10.1126/science.aaz0795), such exoplanets closest to us offer the best opportunities to search for evidence of life outside the solar system.
As part of the “RedDots” observation program, the astronomers observed the red dwarf “Gliese 887” using the HARPS spectrograph at the European Southern Observatory (ESO) in Chile. Using the so-called radial velocity method, which measures minimal star motions caused by orbiting planets, the team discovered regular signals that correspond to orbits of only 9.3 and 21.8 days. The planets are most likely two so-called super-earths – Gliese 887b and Gliese 887c. Super-earths are planets larger than our earth. However, the two planets move very quickly around their star, much faster than Mercury. Scientists estimate the temperature of Gliese 887c to be around 70 degrees Celsius.
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With a distance of around 11 light years, the star itself (Gliese 887) is one of the closest stars to the sun. It is much fainter and just about half the size of our sun. “This means that the habitable zone is closer to Gliese 887 than the distance from the earth to the sun,” explain the astronomers.
The researchers also found two other interesting facts about Gliese 887: “On the one hand, in contrast to our sun, the red dwarf has very few sun or star spots. If ‘Gliese 887’ were as active as our sun, a strong stellar wind – emanating material that can erode the atmosphere of a planet – would probably simply sweep away the atmosphere of the newly discovered super-earths. This means that the planets keep their atmosphere or have a thicker atmosphere than Earth and could possibly harbor life. Secondly, the brightness of ‘Gliese 887’ is almost constant. Therefore, it will be relatively easy to identify the atmosphere of the super earth system, which makes it a key target for the James Webb Space telescope, a successor to the Hubble telescope. ”
“These planets will offer the best opportunities for more detailed studies, including finding life outside of our solar system,” explains Jeffers.
As early as 2016, the RedDots astronomy team found the closest exoplanet to the Sun, which corresponds approximately to the earth’s mass and orbits Proxima Centauri (…GreWi reported). This was followed in 2018 by the announcement of a super-near-Earth planet orbiting Barnard’s star, the second closest star to the sun (… GreWi reported). A system of three planets orbiting the red dwarf star GJ 1061, which is only a little further away from us than GJ 887, was also discovered by the team in 2019 (… GreWi reported).
FURTHER MESSAGES ON THE SUBJECT
Hubble data confirm second planet around Proxima Centauri 15. June 2020
Proxima b: ESPRESSO spectrograph confirms earth-like planets around the nearest star to the sun 29. April 2020
Direct observation: have astronomers photographed super-earth around Proxima Centauri? 19. April 2020
Proxima b: Exoplanet closest to Earth, but probably life-friendly March 12, 2020
Astronomers publish articles on the second rocky planet around Proxima Centauri January 15, 2020
Search for Earth-like planets in the Alpha Centauri system begins 12. June 2019
Proxima Centauri: indications of super earth around the nearest sun neighbor 15. April 2019
Proxima Centauri’s sunburst questions the friendliness of our neighboring star February 27, 2018
Have astronomers found possible clues to other planets around Proxima Centauri? 13. September 2017
Life on planets around our direct neighboring stars may be possible because of high radiation doses 10. April 2019
Cold dust belts circle Proxima Centauri 3. November 2017
Proxima Centauri b: The closest potentially life-friendly exoplanet could be water-rich 19. November 2018
Exoplanet closest to the sun: Proxima Centauri’s friendliness is rather questionable February 12, 2017
Proxima Centauri: The mother star of the next potentially life-friendly planet is closer to the sun than expected October 28, 2016
Assessment: how friendly is Proxima Centauri b? 31. August 2016
Proxima Centauri: Earth-sized planet found in a life-friendly zone around the nearest star 25. August 2016
Those: University of Göttingen
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