it’s just the tip of the iceberg

Just outside our solar system – no more than 30 to 35 light years from Earth – not only is it teeming with red dwarfs, but there are also many worlds to explore.

The first dataset of the CARMENES project has been published. It contains data from about 20,000 observations of 362 nearby red dwarf stars. Spanish and German scientists used the CARMENES instrument on a 3.5-meter telescope at the Calar Alto Observatory in Spain to find the exoplanets. The CARMENES instrument is a very sensitive spectrograph, that is to say an instrument which breaks down light into its different colours. This allows scientists to determine the speed of a star with an accuracy of one meter per second. As a planet orbits a star, the star oscillates back and forth, increasing or decreasing its relative speed relative to Earth. Thus, a flickering star can betray the presence of a planet. Here is an example of a flickering star.

The researchers selected dwarf stars up to ten parsecs (or about 32 light-years) from Earth. It concerns no less than 48% of all known red dwarf stars within ten parsecs of Earth. You might find it hard to imagine ten parsecs, but it’s very close. Our Milky Way is 100,000 light years across. If we were to think of the Milky Way as a big city, we could say that these stars live on the same “street” as our own parent star: the sun.

A total of 59 new exoplanets have been discovered. Among these 59 new exoplanets, 33 extraterrestrial worlds have been discovered for the first time. Another 26 exoplanets have already been spotted as candidate exoplanets, but have now been confirmed.

What is a candidate exoplanet?
A candidate exoplanet is a potential exoplanet whose existence cannot yet be confirmed with certainty. It is therefore also possible that a candidate exoplanet ultimately turns out not to be an exoplanet. Usually, astronomers use multiple telescopes to prove the existence of a candidate exoplanet.

A motley crew of planets
Among the 59 exoplanets are six Jupiter-like planets (with a mass greater than fifty times that of Earth), ten Neptune-like planets (ten to fifty times the mass of Earth) and 43 Earths or super-Earths (up to ten times the mass of our planet). A dozen planets have been discovered in the so-called Goldilocks area around the red dwarf star. It is the habitable zone around a star, where liquid water can exist on the surface of a planet. The Earth is in the habitable zone around the Sun.

Every red dwarf has a planet
In the paper the researchers write that the discovery of the 59 exoplanets is just the tip of the iceberg. It is possible that almost all red dwarf stars contain at least one planet. Many instruments and telescopes are not yet sensitive enough to detect small planets or planets with a large orbital period around a star. So the hunt continues!