New York: Astronomers have discovered a
second exoplanet orbiting its star backwards, a day after the
first "retrograde" exoplanet was spotted.
Using the Japanese Subaru telescope to observe planet
HAT-P-7b, two teams, one led by Joshua Winn of MIT and another
led by Norio Narita at the National Astronomical Observatory
of Japan, have discovered the second exoplanet.
"It is funny that the two good cases for really
misaligned orbits, even retrograde orbits, have come at around
the same time.
"We don`t know if it`s a slowly rotating star that
we`re seeing edge-on, or a really rapidly rotating star that
we`re seeing pole-on. It could be like the solar system -- but
reversed, or it could be going pole over pole. Either way it`s
cool," Winn said.
However, both the teams disagree on the tilt of the
exoplanet`s orbit.
While the US team`s measurements indicate that
the planet either runs backwards along the star`s equator, at
a tilt of about 180°, or it orbits the star`s poles, at a 90°
tilt, the Japanese team claimed that the orbit is inclined by
227° with respect to the star`s equator.
"Statistically, they`re highly discrepant. It could be
due to differences in how the two teams used the telescope, or
in the models they used to interpret their findings. They will
not know for certain until they can exchange their data," Winn
was quoted by the `New Scientist` as saying.
Bureau Report
