Author: Lisa Grossman / Source: Science News
BOSTON — Many sunlike stars are eerie clones, but ours is an individual.
A study of solar twins reveals that the sun’s chemical makeup is surprisingly different from that of its nearby peers, while those stars are almost identical to one another. Since a star and its planets are made from the same materials, that may mean the exoplanets orbiting those stars come in just a few flavors. It also could point to a new way to discover stars with solar systems more like ours.Astronomer Megan Bedell of the Flatiron Institute Center for Computational Astrophysics in New York City and her colleagues studied the elements in 79 “solar twins” — stars with nearly the same temperature, gravity and iron content as the sun. The stars had been observed with the HARPS planet-hunting telescope in Chile, which measures stars’ spectra, or the rainbow of light emitted across different wavelengths. Subtle shifts in the light can reveal an orbiting planet. Spectra can also reveal the abundance of specific elements that make up a star.
“This dataset is really a treasure trove for abundance analyses,” Bedell told the Cool Stars 20 meeting on July 30.
Bedell’s team measured the abundances of 30 elements to 2 percent precision, higher than previous studies had been able to achieve, and confirmed that some elements vary with a star’s age (SN: 10/1/16, p. 25). That was what they expected — younger stars probably formed from clouds of dust…
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