A group of astrophysicists from The
University of Texas at Arlington plans to expand the discussion about a newly
discovered planet orbiting two stars by presenting a study suggesting where an
Earth-type planet could exist in the system.
An illustration of the habitable zone
and extended habitable zone in the Kepler-16 System. The axes are given in
Kepler-16 System made headlines in September when researchers at NASA’s Kepler
space telescope mission revealed the discovery of Kepler-16b, a cold, gaseous
planet that orbits two stars like Star Wars’ fictional Tatooine.
The UT Arlington team, using data from
the Kepler and previous research, have concluded that an Earth-type planet
could exist in the system’s “habitable zone” as an exomoon orbiting
Kepler-16b. They also think an “extended
habitable zone” exists outside the orbit of the gaseous planet, under certain
conditions. To host life in that zone, a terrestrial planet orbiting the two
stars would need to have high levels of greenhouse gases in its atmosphere such
as carbon monoxide or methane, they said.
Billy Quarles, a doctoral student in
the UT Arlington College
of Science, will present the findings at the annual meeting of the
American Astronomical Society on Jan. 9 in Austin. Co-authors on the work are
UT Arlington Department of Physics professor Zdzislaw Musielak and associate
professor Manfred Cuntz.
“This is an assessment of the
possibilities,” said Musielak, a two-time winner of the prestigious Humboldt
Prize for his work in astrophysics. “We’re telling them where a planet has to
be in the system to be habitable. We’re hoping they will look there.”
The Kepler Mission is a space telescope
launched by NASA in 2009 that measures light from 150,000 stars. Scientists
working with Kepler data look for changes in stellar brightness that suggest a
transit, or a planet passing in front of a star. They use measurements of the
star’s luminosity to determine whether the planet is in a “habitable zone,” an
area where the planet would be orbitally stable and where conditions hospitable
to the formation and sustainment of life could exist.
The UT Arlington team based their
conclusions about an “extended habitable zone” outside the orbit of Kepler-16b
on work by scientists such as NASA’s Michael A. Mischna. That research says
life could be found outside the traditional habitable zone, but it requires a
more extreme planetary atmosphere, one in which chemicals in the atmosphere
create a strong back-warming effect, Quarles said.
“There is less light from the star, so the
planet itself has to maintain more heat,” he said.
In addition to their presentation at
the AAS meeting, the UT Arlington team hopes to publish its findings soon.
Cuntz said the work demonstrates how the search for habitable planets requires
both the development of theory and observations.
“This work is informed by observations
and it has the potential to trigger more observations,” he said.
Pamela Jansma, dean of the UT Arlington
College of Science, said the University is proud to have the team of researchers
selected from scientists across the country to present at the American
Astronomical Society meeting.
“This is the type of work that captures
the imaginations of students and gets them excited about exploring a career in
science. It’s certain to catch the attention of other researchers and spark
even more examination,” she said.
Arlington is a comprehensive research institution of 33,439 students in the
heart of North Texas. Visit www.uta.edu to learn more.