In this specific case, the definition of Earth-like is if the exoplanets can simultaneously retain gases similar to the ones present in the atmosphere of Earth and host liquid water.
– We use a robust theoretical analysis of the exoplanets using the known measured properties such as mass and radius of the exoplanet along with the temperature of the star, Samuel Konatham, PhD candidate in Atmospheric Science explains.
– We use simple law of physics to calculate the velocities that the atmospheric gases can achieve and determine if the gas can escape from the gravity of the exoplanets and then from the atmosphere. Over time, the gases that can escape should disappear from the atmosphere. Based on the gases that can be retained, they determine their similarity to Earth and their potential habitability.
An exoplanet is a planet situated outside our solar system. The closest exoplanet is Proxima Centauri b, about 4.3 light-years away. A light-year is the distance that light travels in one year: 9,46 trillion kilometers. So far, there are more than 4,200 exoplanets found. The astronomical distances pose various technological problems to observe and study the atmospheres of these exoplanets.
– The information we have about exoplanets is scarce and not all the needed parameters for our study are available. We have considered the 3,705 exoplanets where these parameters are measured and from that list, we have found that 45 exoplanets that are potentially habitable, says Samuel Konatham.
The model that Samuel Konatham and his LTU PhD supervisors, Prof. Martin-Torres and Prof. Zorzano have developed, provides a list of exoplanets that could have an Earth-like atmosphere and hence are potentially habitable. The results can be used when prioritizing observations by space telescopes such as James Webb Space Telescope (JWST) and CHEOPS in the search for habitable exoplanets.
Do your results suggest that there could be – or was – life on these planets?
– Currently, we are far from answering this age-old question. Scientific evidence of today suggests to the curious mind that there are numerous possibilities, and there is still a lot for us to explore within our solar system and the vast universe.
The study has been published in the journal Proceedings of the Royal Society A.