University of Florida astronomers find that hundreds of millions of planets orbiting dwarf stars in the Milky Way could potentially harbor life, occupying a ‘Goldilocks’ orbit that allows them to withstand extreme tidal forces and retain liquid water, according to data from NASA’s Kepler and Gaia telescopes.
Our familiar, warm, yellow sun is a relative rarity in the Milky Way. By far the most common stars are considerably smaller and cooler, sporting just half the mass of our sun at most. Billions of planets orbit these common dwarf stars in our galaxy.
To capture enough warmth to be habitable, these planets would need to huddle very close to their small stars, which leaves them susceptible to extreme tidal forces.
In a new analysis based on the latest telescope data, University of Florida astronomers have discovered that two-thirds of the planets around these ubiquitous small stars could be roasted by these tidal extremes, sterilizing them. But that leaves one-third of the planets – hundreds of millions across the galaxy – that could be in a Goldilocks orbit close enough, and gentle enough, to hold onto liquid water and possibly harbor life.
UF astronomy professor Sarah Ballard and doctoral student Sheila Sagear published their findings the week of May 29 in the Proceedings of the National Academy of Sciences. Ballard and Sagear have long studied exoplanets, those worlds that orbit stars other than the sun.