New Technique to Measure Stars' Gravity May Help Us Discover Alien, Habitable Worlds

Scientists may have found a new way to measure the pull of gravity at the surface of a star, which could help them find new, distant worlds. The information is key for determining whether or not these planets have the possibility of hosting life.

Knowing the surface gravity of a star is essentially knowing how much you would weigh on that star. If stars had solid surfaces on which you could stand, then your weight would change from star to star. On our own sun, you'd weigh 20 times more than on Earth. On a red giant star, though, you'd be 50 times lighter.

So what is the new technique? It's called autocorrelation function timescale technique, or timescale technique for short. It uses subtle variations in the brightness of distant stars recorded by satellites.

The latest method has an accuracy of about four percent, for stars too distant and too far to apply current techniques. Since surface gravity depends on the star's mass and radius, just as your weight on Earth depends on its mass and radius, the new technique will allow astronomers to better gauge the masses and sizes of distant stars.

"If you don't know about the star, you don't know about the planet," said Jaymie Matthews, the co-author of the new study, in a news release. "The size of an exoplanet is measured relative to the size of its parent star. If you find a planet around a star you think is sun-like but is actually a giant, you may have fooled yourself into thinking you've found a habitable Earth-sized world. Our technique can tell you how big and bright is the star, and if a planet around it is the right size and temperature to have water oceans, and maybe life."

The findings could be huge when it comes to searching for life on other planets. In theory, it could use data from future space satellites to narrow down the locations to look for life.

The findings are published in the journal Science Advances.

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