agencies
Saturday, 03 June 2023 03:00 PM
New research shows that most of the stars in Our galaxy is the Milky Way They are of class M, known as red dwarfs, which are smaller and redder than the Sun, and many of them may have the potential to host life.
And a new analysis of data from the planet-hunting Kepler mission found that a third of the planets around red dwarfs could be suitable for life, which means that hundreds of millions of planets could potentially exist. habitable planets In the Milky Way alone.
For the analysis, astronomers at the University of Florida incorporated new information from the European Space Agency’s Gaia satellite, which accurately measures the distances and motions of stars, to adjust the measurements of the orbits of the exoplanets.
For each orbit, the scientists wanted to determine an indicator known as eccentricity (or eccentricity), which is a measure of how far a planet’s path extends around its star.
“Distance is really the key piece of information that we were missing before that allows us to do this analysis now,” Sheila Sager, an astronomy graduate student at the University of Florida and lead author of the study, said in a statement.
Planets around red dwarfs with large eccentricities — highly elongated elliptical orbits — end up “fried” by the star if they are close enough, in a process called tidal heating.
The tidal heating is caused by the planet’s precarious orbit, which leads to expansion and compression from the star’s gravity. Just like rubbing your hands together, all this motion results in heat from friction.
If there is too much heat, the planet loses its water, along with the chances of life developing on its surface. Since it is essential to life as we know it, water in general is at the center of the search for habitable worlds beyond Earth.
If a planet orbits a red dwarf far away, this distance may prevent tidal heating, but then the planet will be very cold and lack the warmth necessary for life.
Therefore, exoplanets around red dwarfs must live close to their stars in order to get a chance to get hot enough for life, which puts them at risk of tidal overheating if their orbits are not perfectly circular.
“Only for these young stars is the habitable zone close enough for these tidal forces to be relevant,” Sarah Ballard, a University of Florida astronomer and study co-author, said in the release.
With their new and improved measurements of the large number of exoplanets discovered by the Kepler space telescope, Sager and Ballard found that two-thirds of the planets around red dwarfs would be affected by the heat of their host stars, burning their chances of life.
But that leaves a third of the planets in the so-called Goldilocks region where liquid water could theoretically exist — along with the possibility of life.
The team found that star systems with multiple planets are more likely to have circular orbits, which allows them to retain liquid water. It is believed that stars with one planet are more exposed to strong tidal forces, which remove traces of the biofluid, and the results were published in the journal PNAS.
