In work that should make it easier to determine which planets are capable of supporting life and which are not, an international team of researchers has come up with a new way to measure the pull of gravity from the surface of the stars orbited by exoplanets.
Their findings, published Friday in the journal Science Advances, will help determine how much a person or other biological lifeform would weigh on that star if it had a solid surface. Using this new method could measure stars too far away for current techniques.
In their paper, Thomas Kallinger from the University of Vienna and his colleagues explained that a person would weigh 20 times more on the sun than they do on Earth, and 50 times less on a red giant star. Since surface gravity depends on the radius and mass of a star, it can be used to discern the sizes and masses of distant stars, they explained.
“The size of an exoplanet is measured relative to the size of its parent star,” Jaymie Matthews, a professor at the University of British Columbia and study co-author, said in a statement. “If you find a planet around a star that 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.”
Findings could help find distant, potentially habitable exoplanets
This new approach, which is called the autocorrelation function timescale technique, can be used to determine how big and bright a distant star is, and whether a planet orbiting said star is just the right size and temperature to support liquid water on its surface, Matthews added.
The autocorrelation function timescale technique uses slight variations in the brightness of stars detected by satellites such as NASA’s Kepler mission, and could be used to study planets so far away that not even the basic characteristics of the stars they orbit can be accurately measured.
“The timescale technique is a simple but powerful tool that can be applied to the data from these searches to help understand the nature of stars like our Sun and to help find other planets like our Earth,” said Kallinger, the lead author of the new study. His team’s work may help narrow down the list of research targets for future surveys searching for potentially habitable exoplanets.
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