A super-Earth orbiting its star smaller than the Sun.

Discovered by astrophysicist Hiroki Harakawa and his colleagues at the National Astronomical Observatory of Japan, the planet named Ross 508 b is located approximately 36.5 million light years from us.

Its approximate mass, about four times larger than that of Earth, indicates that it will be rocky instead of gas.

The star it orbits is a faint red dwarf that is almost five times smaller and smaller than the Sun.

The Japanese team announced this using the IRD (infrared Doppler) instrument installed on the Subaru telescope, located in the shield of the Mauna Kea volcano, on the island of Hawaii. This spectrometer specializes in detecting exoplanets around red dwarf stars that emit most of their energy in infrared.

Ross 508 b was not directly identified using the radial velocity technique which has detected more than 18% of the exoplanets confirmed to date. This method involves observing the Doppler-Fizeau effect, a slight shrinkage, in the spectrum of the star on which a planet rotates.

Scientists now want to determine if Ross 508 b has an atmosphere.

Ross 508 b orbits its star Ross 508 in full for 10.77 days and is already away only 8 million kilometers. This will be at the inner limit of living area around the planet.

The concept of the habitable zone, i.e., the distance between a planet and its star, is considered a key element in a planet’s capacity to retain elements on its surface that are essential to the appearance of life as we know it, including the liquid water.

In our solar system, Venus rotates near the inner boundary of the habitable zone, and Mars near the outer boundary. Other factors may affect whether this zone expands or constricts.

More than 5000 exoplanets have been discovered

Last March, NASA’s official census passed the threshold of 5,000 exoplanets detected.

As of June 7, at least 5035 were officially identified in more than 3775 planetary systems.

More than 9017 additional exoplanets are currently awaiting confirmation.

NASA’s official archive records only exoplanet discoveries that are the subject of peer-reviewed scientific articles and whose existence has been confirmed by multiple detection methods or analytical methods.

Other methods of observation

The transit strategy has so far confirmed the presence of most of them (76.6%) to date. It consists of detecting a decrease in the brightness of a star when an object passes in front of it.

The gravitational microlensing technique constitutes 2.6% of the findings. This effect occurs when a star’s gravitational field distorts spacetime, diverting light from a distant star behind it, like a lens.

Direct observation, which is very difficult, allows 1.2% of sightings. Because they are small and fuzzy, the planets can easily disappear in the light of the bright giant stars around which they orbit. However, thanks to current telescopes, there are special circumstances in which a planet can be directly observed. Three Quebecers also participated in creating the first direct image of the exoplanet. They received the Scientist of the Year 2008 title from Radio-Canada for their achievement.

The detail of this discovery is the subject of an article published in the review ofAstronomical Society of Japan (New window).