Third Of Milky Way’s Most Common Planets Could Harbor Life

A study based on the latest telescope data shows that one-third of the planets orbiting the most frequent stars in the Milky Way galaxy may retain liquid water and possibly sustain life.

Our galaxy’s most common stars are far smaller and cooler, with only half the mass of the Sun at most. These typical dwarf stars are orbited by Billions of planets.

The study, which was published in the journal Proceedings of the National Academy of Sciences, found that two-thirds of the planets orbiting these common tiny stars might be burnt by tidal extremes, rendering them sterile.

However, one-third of the planets-hundreds of millions across the galaxy– could be in a Goldilocks orbit, close enough and gentle enough to be potentially habitable.

A doctoral student at the University of Florida (UF), US, Sheila Sagear said, “I think this result is really important for the next decade of exoplanet research because eyes are shifting towards this population of stars”.

“These stars are excellent targets to look for small planets in an orbit where it’s conceivable that water might be liquid and therefore the planet might be habitable”, Sagear added.

Sagear and UF astronomy professor Sarah Ballard estimated the eccentricity of a sample of more than 150 planets around M dwarf stars the size of Jupiter.

The more eccentric an orbit is, the more oval it is. An eccentric orbit can subject a planet to tidal heating if it revolves near enough to its star, around the same distance as Mercury orbits the Sun.

Friction heats up the planet as it is stretched and twisted by varying gravitational pressures on its erratic orbit. At its most extreme, this might roast the globe, destroying all possibility of liquid water.

Ballard stated, “It’s only for these small stars that the zone of habitability is close enough for these tidal forces to be relevant”.

The researchers analyzed data from NASA’s Kepler telescope, which collects data on exoplanets as they pass in front of their host stars.

They concentrated particularly on how long it took the planets to cross the face of the stars in order to measure the planet’s orbit.

Additionally, they used fresh information from the Gaia telescope, which has calculated the separations between billions of stars throughout the galaxy.

Sagear stated that the distance is really the key piece of information we were missing before that allows us to do this analysis now.

The researchers discovered that stars with only many planets were more likely to have the kind of circular orbits necessary to support the presence of liquid water.

According to the researchers, stars with only one planet were the most likely to experience tidal extremes that would sterilize the surface.

Researchers stated that since one-third of the planets in this small sample had gentle enough orbits that might potentially support liquid water, the Milky Way likely contains hundreds of millions of promising targets to probe for signs of life outside our solar system.

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