Originally Posted: February 14, 2017
Astronomers are reporting a rare star as big — or bigger — than the Earth’s sun and that is expanding and contracting in a unique pattern in three different directions.
The star is one that pulsates and so is characterized by varying brightness over time. It’s situated 7,000 light years away from the Earth in the constellation Pegasus, said astronomer Farley Ferrante, a member of the team that made the discovery at Southern Methodist University, Dallas.
Called a variable star, this particular star is one of only seven known stars of its kind in our Milky Way galaxy.
“It was challenging to identify it,” Ferrante said. “This is the first time we’d encountered this rare type.”
The Milky Way has more than 100 billion stars. But just over 400,900 are catalogued as variable stars. Of those, a mere seven — including the one identified at SMU — are the rare intrinsic variable star called a Triple Mode ‘high amplitude delta Scuti’ (pronounced SKOO-tee) or Triple Mode HADS(B), for short.
“The discovery of this object helps to flesh out the characteristics of this unique type of variable star. These and further measurements can be used to probe the way the pulsations happen,” said SMU’s Robert Kehoe, a professor in the Department of Physics who leads the SMU astronomy team. “Pulsating stars have also been important to improving our understanding of the expansion of the universe and its origins, which is another exciting piece of this puzzle.”
The star doesn’t yet have a common name, only an official designation based on the telescope that recorded it and its celestial coordinates. The star can be observed through a telescope, but identifying it was much more complicated.
A high school student in an SMU summer astronomy program made the initial discovery upon culling through archived star observation data recorded by the small but powerful ROTSE-I telescope formerly at Los Alamos National Laboratory in New Mexico.
Upon verification, the star was logged into the International Variable Star Index as ROTSE1 J232056.45+345150.9 by the American Association of Variable Star Observers at https://www.aavso.org/vsx/index.php?view=detail.top&oid=473892.