UCSB: Scientists Discover a New Type of Pulsating Star

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UCSB: Scientists Discover a New Type of Pulsating Star

Post by bystander » Thu Aug 08, 2019 4:39 pm

Star Light, Star Bright: Scientists Discover a New Type of Pulsating Star
University of California, Santa Barbara | 2019 Aug 01
Scientists can tell a lot about a star by the light it gives off. The color, for example, reveals its surface temperature and the elements in and around it. Brightness correlates with a star’s mass, and for many stars, brightness fluctuates, a bit like a flickering candle.

A team of scientists led by UC Santa Barbara researcher Thomas Kupfer recently discovered a new class of these pulsators that vary in brightness every five minutes. ...

Initially, Kupfer and his colleagues at Caltech were searching for binary stars with periods less than an hour in observations from the Zwicky Transient Facility, a sky survey at the Palomar Observatory near San Diego. Four stood out due to large changes in their brightness over just a few minutes. Follow-up data quickly confirmed that they were indeed pulsators, not binary pairs. ...

Kupfer has now identified the stand-out stars as hot subdwarf pulsators. A subdwarf is a star about one-tenth the diameter of the Sun with a mass between 20 and 50% that of the Sun. They’re incredibly hot -- up to 90,000 degrees Fahrenheit, compared to the Sun’s 10,000 F. ...

The discovery came as a surprise. Scientists hadn’t previously predicted the existence of these stars, Kupfer explained, but in retrospect they fit well into the leading models of stellar evolution. ...

A New Class of Large-Amplitude Radial-Mode Hot Subdwarf Pulsators ~ Thomas Kupfer et al
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