ARLINGTON - Work by a team of University of
Texas at Arlington astronomers could significantly broaden astrophysicists'
search for planets in other solar systems by changing the way they think about
the orbiting bodies.
If correct, the findings could
increase the opportunities for the discovery of new planets in candidate
The paper by Manfred Cuntz, UT
Arlington associate professor of physics, and Jason Eberle, a doctoral
candidate from UT Arlington, is being published Oct. 1 in the American
Astronomical Society's Astrophysical Journal Letters. "On the reality of the
suggested planet in the ν Octantis System" is already available online.
In the paper, the two scientists explore the possible existence of a proposed
planet in a binary star system 69 light years, or 400 trillion miles, from
Based on six years of data,
observers have suggested a planet may exist in the ν Octantis system, a star
system visible only from the southern half of the globe, particularly from
Antarctica. The observing technique is based on radial velocity variations or
RV readings of the orbiting planet's effect on its host star - a slight wobble
created by the planet's pull. Surprisingly, the planet of the system seemed to
be outside of the commonly accepted zone where such an orbit could exist
without disruption from the gravitational force of the second star in the
binary system, Cuntz said.
and Cuntz examined the data by performing detailed time-dependent simulations
of orbital stability. They concluded
there is a significant chance that the planet is indeed able to exist but in a
retrograde orbit. A retrograde orbit means the planet is orbiting the primary
star in a different direction compared to the orbit of the secondary star. This
would allow for a wider area of orbital stability, the study says.
an orbit is previously unheard of for a planet in an extrasolar planetary
system, but this type of orbit occurs for some moons of planets in our Solar
System. If confirmed, the existence of such a planet would significantly
enhance the search for planets in multiple stellar systems, including the
search for those that could potentially support life, according to Cuntz.
our theoretical studies turn out to be applicable to the ν Octantis system, they
will provide evidence for the first case of a planet in a retrograde orbit in a
stellar binary system," said Cuntz. Previously, retrograde planetary
orbits have been detected for planets around single stars in regard to the
stellar rotational axis.
research team's findings are likely to gain attention, according to another
expert in the field.
results of Eberle and Cuntz are important for the big hot topic of astronomy,
namely extrasolar planets, and especially interesting for the dynamics of
planets in double stars," said Rudolf Dvorak, a professor at the Institute for
Astronomy at the University of Vienna. "Note that in the solar neighborhood more
than 60 percent of the stars are not single."
and Eberle's study says there is still a slim chance that the suggested planet
is in a prograde orbit, traveling in the same direction as the primary star's
partner star. This is highly unlikely, as it would require detailed assumptions
concerning the orbital parameters of the planet.
existence of a planet in ν Octantis was first suggested by a research team led
by David Ramm of the Department of Physics and Astronomy at the University of
Canterbury in New Zealand.
The University of Texas at Arlington is an Equal Opportunity and Affirmative Action employer.