Discovered L 98-59 F, a “super-deer” light years from the earth, in the habitable area of its red dwarf star, fueling the search for extraterrestrial life.
Instead of the sun … there is a red dwarf
The mother star is a cold and weak “red dwarf”, already known to host a compact system of small rocky planets. Red dwarfs are small -mass stars, about 0.1-0 times that of the sun. They have a relatively low surface temperature (about 2,500–3,500 k), for this reason they appear red. They burn hydrogen very slowly, so they can live hundreds of billions of years. Although they are the most common in the universe, their light is so weak that they make them invisible to the naked eye.
The new Esopiana, described in a study published in the magazine Earth and Planetary Astrophysicsit is a “super-terme”: it has a minimum mass of 2.8 times that of our planet and orbit around its star in 23 terrestrial days. What makes the discovery particularly relevant is that the 98-59 F is located within the so-called “habitable area”-a range of distance from the star in which, if the right weather conditions existed, there could be water in the liquid state. This is one of the fundamental premises for the potential presence of life as we know it.
“Finding a tempered planet in such a compact system makes this discovery particularly exciting,” commented Charles Cadieux, post-dictated researcher of the University of Montréal and first author of the study. “It shows how different planetary systems can be and how important it is to continue studying the worlds around the small mass stars”.
How the planet was discovered
The planet does not transit in front of its star from our point of view, so it was not possible to observe it with traditional transit methods. Its presence was detected thanks to the radial speed technique, monitoring the slight movements of the star caused by the gravitational force of the planet.
The analysis was made possible thanks to the data collected by the Harps spectrographers and Espresso of the Southern European Observatory (ESO), combined with the observations of the NASA Tess Space Telescopes and James Webb (JWST). The researchers used advanced techniques to filter the “noise” produced by the star activity, thus managing to precisely measure the properties of all five planets of the system.
A varied planetary system
The internal planets of the L 98-59 system show extremely different characteristics. The planet closest to the star, L 98-59 B, has a diameter of 84% of the terrestrial one and a mass equal to half. It is one of the smaller exoplanets ever detected.
The analyzes suggest that the sea forces could feed the volcanic activity on the two closest planets, while the third planet has a surprisingly low density, suggesting that it may be a world rich in water, very different from any planet in our solar system. This diversity offers astronomers a unique opportunity to study how planetary systems evolve and evolve. According to Cadieux, “These new results give us the most detailed picture never obtained of this fascinating system.”
Next steps: look for an atmosphere
L 98-59 is a small and relatively close star, characteristics that make its planets ideal for future atmospheric studies. If the 98-59 F possessed an atmosphere, advanced telescopes such as James Webb could even detect the presence of water vapor, carbon dioxide or-potentially-biological clues.
The discovery of L 98-59 F represents another step towards one of the most ambitious objectives of modern astronomy: finding a world, or even inhabited, outside our solar system.
