Researchers discover super earths near a nearby red dwarf star

At least two super earths orbit one of the nearest stars. Because of the short distance of eleven light years, this planetary system can be studied particularly well.

Super earths, GJ 887.

Researchers have discovered a planetary system near a red dwarf star in our immediate cosmic neighbourhood.

The star with the catalogue number GJ 887, which is only eleven light years away, is orbited by at least two planets of the Super Earth class, possibly even three.

This was reported by Sandra Jeffers' team from the University of Göttingen in the journal "Science". The scientists believe that the planetary system could become one of the most studied because of its short distance.

Planets are usually outshined by home stars

Red dwarfs are the most common type of star in our home galaxy, the Milky Way. Most of them probably have planets. The nearest planet outside our solar system also orbits a red dwarf.

Picture of Proxima Centauri 4.2 light years away from earth.
Proxima Centauri, 4.2 light years away. 

GJ 887 is the twelfth-next star to the Sun. Jeffers' team observed it every night for three months and combined this data with archived observational data from almost 20 years.

The analysis showed that the red dwarf fluctuates slightly, sometimes moving towards the observer and sometimes away from him.

The reason for this wobbling is the planets, which are pulling the star with their gravity while orbiting it.

Hardly any of the planets outside our solar system can be observed directly; they are usually outshined by their home star.

Super earth too hot for life

The two confirmed planets are heavier than Earth, but lighter than Uranus, the smallest gas planet in our system. They therefore fall into the category of Super Earths.

  • Both orbit the red dwarf at a short distance, one in about 9 days, the other in just under 22 days. 
  • They receive about two and a half times and eight times as much energy from their star as the Earth receives from the Sun. 
  • According to model calculations, the average temperature on these stars is 80 and almost 200 degrees Celsius respectively - too hot for life.

However, the data contain references to a third planet with an orbital period of about 50 days. This would be located in the so-called habitable zone around the red dwarf, where moderate temperatures prevail and the existence of liquid water is possible.

Red dwarf offers stable conditions

Liquid water is considered to be the basic prerequisite for life as we know it. Should the existence of this third planet be confirmed, it could be an interesting target for the search for extraterrestrial life.

This is because GJ 887 is a remarkably a quiet star for a red dwarf, offering stable conditions.

"In addition, the short distance allows the next generation of space telescopes to study possible atmospheres of the planets in this system," the researchers say.

The "James Webb" space telescope, for example, which is to be launched into space next year, can detect the signatures of gases such as carbon dioxide in the starlight reflected by the planets.