Evidence of Potentially Habitable Exoplanets Abundant in Milky Way Galaxy

Monday - May 29 2023, 23:32 UTC - 1 year ago

A new study has attempted to narrow down the possibilities of discovering potentially habitable exoplanets within the Milky Way, according to which roughly one-third of the galaxy's planets may be in the Goldilocks zone. The team used data from the Kepler and Gaia telescopes and noted that stars with multiple planets in a circular orbit are more likely to retain liquid water. Despite this, the authors note that searching for lifeforms beyond Earth could require developing more advanced technology.

The ultimate goal of space exploration has been to find habitable worlds similar to Earth that have all of the ideal conditions for life to thrive. Scientists have gathered a plethora of evidence of potentially habitable worlds over decades of scientific research, but none come close to our one-of-a-kind blue world. Despite the oddities, the hope of finding a habitable exoplanet continues. A new study has attempted to narrow down the possibilities of discovering potentially habitable exoplanets within the Milky Way.

According to the calculations of University of Florida professor Sarah Ballard and doctoral student Sheila Sagear, roughly one-third of the galaxy's planets may be in the Goldilocks zone, which is an ideal orbit that allows these worlds to retain liquid water and possibly sustain any form of life.

Finding the ideal orbit is the key .

The team measured the "eccentricity" of over 150 planets that orbit M dwarf stars — stars about the size of Jupiter. Orbital eccentricity determines the shape of the planet’s orbit around its host star, for instance, whether the planet has an elliptical orbit or deviates from a perfect circle. The researchers used data from the Kepler and Gaia telescopes. According to the study, Kepler assisted in determining how exoplanets move in front of their host stars, while Gaia measured the distance between stars in the galaxy. "The distance is really the key piece of information we were missing before that allows us to do this analysis now," noted Sagear, one of the authors of this new study, in an official statement.

Following a thorough examination of the data, the authors noted that stars with multiple planets in a circular orbit are more likely to retain liquid water. Star systems with only one planet, on the other hand, may undergo "tidal extremes that would sterilize the surface." .

As a result, there are only a small fraction (one-third) of planets in this sample size that may lie in the Goldilocks zone. Despite this, one-third of the planets imply "hundreds of millions" of potentially promising liquid world candidates for searching for any life forms beyond our precious Earth.

"I think this result is really important for the next decade of exoplanet research because eyes are shifting toward 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," concluded Sagear.

The results have been published in the journal Proceedings of the National Academy of Sciences.