American scientists have identified specific star systems where up to 1/3 of the planets could be teeming with water and life, rather than just a solitary Earth like in our Solar System.
A research team from the United States has focused on red dwarf stars, which are significantly smaller and cooler than our Sun. Their work suggests that these stars are the most promising candidates for hosting habitable worlds.
“These stars are excellent targets for searching for small planets in orbits where water can remain in liquid form, and therefore could be habitable planets” – said co-author Sheila Sagear from the University of Florida.
Graphic of Gliese 414, a red dwarf star system believed to contain habitable planets – (Image: SCI-NEWS).
Dr. Sagear’s team measured the eccentricities of a sample of 150 planets orbiting M-type red dwarf stars.
They found that many planets are located too close to their red dwarf stars, at distances comparable to that of Mercury to the Sun.
Such planets undergo a process known as tidal heating due to the influence of their parent stars, which can literally “cook” them and potentially eliminate any chance of retaining liquid water. However, as much as 1/3 of the observed planets lie outside this orbital zone and possess other factors that could allow them to maintain liquid water.
Liquid water is crucial; for example, our Solar System has three planets within the “habitable zone”, but Venus and Mars cannot retain liquid water, making them uninhabitable or, if life existed, it has since gone extinct, according to studies.
These should be planets within red dwarf star systems, as the interactions among planets often help them maintain stable, circular orbits, a condition conducive to life.
This means that our Milky Way galaxy is a promising place to search for extraterrestrial life, as red dwarfs are the most common type of star in the galaxy.
