Astronomer John Gizis of the University
of Delaware, working with data obtained by NASA's Kepler telescope, is
studying a highly unusual dwarf star and its powerful flares that may
hold clues to the likelihood of life on other planets as well as to the
behavior of our sun.
Department of Physics and Astronomy,
discovered the star two years ago using a ground-based telescope and
now has conducted additional research using Kepler observations over the
past two years.
Known as an L-dwarf, this coolest type of star is about 53 light
years from Earth. About once a week, the star flares, heating up from
its usual 3,700 degrees Fahrenheit to about 14,000 degrees in just three
minutes, and then slowly cooling again.
"We saw these white-light flares, which were a first for such a cool
star," Gizis said. "We hope we can use what we're learning to understand
what's happening with our sun how flares work there and how magnetic
fields in stars behave."
In addition, he said, the powerful flares may indicate that
conditions for life on other planets near such activity are more
dangerous than previously thought.
Kep
ler, the NASA mission subtitled "A Search for Habitable Planets,"
launched in 2009 and orbited the sun, focusing on a single, large
section of sky. With recent equipment malfunctions, scientists believe
the mission has now come to an end.
G
izis expects to spend about six more months analyzing data that
Kepler has already gathered and to then continue studying the L-dwarf
with different equipment.
"What was really marvelous about Kepler is that it was able to watch
about 160,000 stars for four years without a break, which would have
been impossible otherwise," Gizis said. "And now that we know what we're
looking for, we can continue to observe the L-dwarf with other
telescopes."
The star, designated W1906+40, is smaller than Jupiter, cooler than
the sun and "many billions" of years old, possibly a similar age as the 4
billion-year-old sun, he said. It's closer to Earth than the other
stars Kepler studied, but because it's dimmer, it was more difficult to
find.
"I'm an observational astronomer," Gizis said. "I like discovering new stars."
He presented his discoveries June 3 at the 222nd meeting of the
American Astronomical Society, and the results are to be published in an
upcoming issue of The Astrophysical Journal. His presentation at the society's meeting has resulted in media attention, with articles appearing in publications including The Economist and Nature World News.
The research was funded by a NASA grant.
