Exploring the universe

Two confirmed Super-Earths around near by star

A new system has been discovered in June 2020. The star known as Gliese 887 or Lacaille 9352  is only located at a distance of about 10.74 light-years from Earth. That makes it the eleventh closest star system to our solar system. The star is a low mass M-type star half the size of our Sun and is the brightest M-type star in the sky. The star is still too faint to see with the naked eye but can be seen with a small telescope. The star has the fourth known highest velocity and is moving at 6.9 arcseconds per year (0.000277778 degrees). The discovery was made by using the HARPS spectrograph at the European Southern Observatory in Chile and HIRES in Hawaii. By using the radial velocity method. 

Image credit: NASA/JPL-Caltech

The system has two confirmed planets both super-earth sized. Gliese 887 b has a mass of 4.2 of Earth and an orbit period of 9 days and Gliese 887 c has a mass of 7.6 of Earth and an orbit period of 22 days. Both planets are closer to the star than the inner edge of the habitable zone. Gliese 887 c has an estimated temperature of 70 degrees celsius. There was a third signal with a period of 50.7 days in the data that suggest that there is a third planet in the habitable zone, but that may be due to stellar activity.

The good news is that the star is a so-called quiet star with not too much stellar activity much lower than our Sun. Which means that the planets will be able to retain their atmosphere. The brightness of the star is almost constant and that would make it easier to detect any atmospheres on the planet. This makes the new system a candidate for more studies for the upcoming James Webb Space telescope.

GJ 887

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