This gray mouse appears to be regularly in the spotlight.

The star GJ 887 is one of the brightest M stars in the night sky. M stars are so-called red dwarfs: cool, not so large and therefore often more difficult to see from Earth than giant stars such as Sirius. Fortunately, GJ 887 is very close to Earth, only 11 light-years away.

Scientists think red dwarfs are the perfect locations to look for habitable planets. Only in our Milky Way are there possible sixty billion habitable exoplanets near red stars. This is because red dwarfs live much longer than larger stars, such as our sun. In addition, red dwarfs are often calmer and planets are less affected by solar flares. After all, red dwarf stars often harbor rocky planets, such as Mars and Earth.

Incidentally, there are not only advantages. Recently there has been a visible shift towards orange dwarf stars (K stars). That’s because planets orbiting red dwarfs are often bombarded with dangerous ones X-ray and ultraviolet (UV) radiation, which can be up to hundreds of thousands of times more intense than what the earth receives from the sun. Circling exoplanets are therefore not sure of their lives and can be deprived of their atmosphere at any moment. It means that these planets are possible be bone dry.

Bursts in UV light
Now it appears that the red dwarf star GJ 887 is also less boring than expected. Two (possibly three) planets revolve around this star. Scientists observed the star for 27 days with the TESS satellite, but did not see any large solar flares. Yet historical Hubble data shows that GJ 887 hurls solar flares into space every hour. These peaks in brightness are only clearly visible in far ultraviolet light (122–200 nm) and were missed by TESS.

No atmosphere?
It shows again how difficult it is to predict whether an exoplanet is habitable or not. In ‘normal’ light, GJ 887 appears to be a fine parent star, but ultraviolet light shows that the star is continuously bombarding the planets with radiation. The exoplanets at GJ 887 may have (almost) no atmosphere anymore, like Mars. In that case, there is a very good chance that there is no life on these alien worlds.