14 DAY TRIAL // A paper recently published in the journal Monthly Notices of the Royal Astronomical Society and authored by researchers with the Universities of Arizona and Washington should make it easier to find life outside the solar system.
Thus, this paper shows that, when compared to exoplanets doomed to float about in space all by themselves, those lucky enough to have a companion nearby are more likely to accommodate for various forms of life.
As shown by previous investigations, planets tend to cool as they age. Specifically, their molten cores turn into solids, and heat-generating activity is reduced up to the point when the planets can no longer host life, Science Daily informs.
According to specialists with the Universities of Washington and Arizona in the US, planets that have a companion are less likely to witness their molted cores solidifying and to experience a drastic drop in heat-generating activity.
This is because one such companion is bound to exert a gravitational pull strong enough to result in tidal heating when in conjunction with the influence of a nearby star, and keep planets outside the solar system warm and fuzzy enough to be able to sustain life.
In the journal Monthly Notices of the Royal Astronomical Society, specialists explain that companion planets help keep others in their proximity stay habitable by causing them to have a noncircular orbit, i.e. to constantly move closer and farther from their host star.
It is precisely this variation in how close a planet gets to come to a star while busy orbiting it that encourages habitability by triggering regular changes in the planet's shape and birthing frictional heating, the scientists behind this research project argue.
“When the planet is closer to the star, the gravitational field is stronger and the planet is deformed into an American football shape. When farther from the star, the field is weaker and the planet relaxes into a more spherical shape. This constant flexing causes layers inside the planet to rub against each other, producing frictional heating.”
“The outer planet is necessary to keep the potentially habitable planet's orbit noncircular. When a planet's orbit is circular, the gravitational pull from its host star is constant, so its shape never changes, and there is no tidal heating,” says specialist Rory Barnes with the University of Washington.
Evidence collected with the help of computer models indicates that, all things considered, such frictional heating can also affect planets orbiting stars about one-quarter the mass of our Sun. Such planets could therefore host life, Rory Barnes and fellow researchers argue.
The University of Washington specialist concludes that, even if they do not accommodate for life forms to begin with, such planets might be just right for us to inhabit at some point. “Perhaps in the distant future, after our sun has died out, our descendants will live on worlds like these,” the researcher says.