Star-skimming Planet
Brian Jackson's study focuses on planetary candidates with orbital
periods so close to their host stars that they are nearly skimming the
stellar surface. This artist's conception from the European Southern
Observatory depicts the exoplanet Corot-7b, which is so close to its
Sun-like host star that it must experience extreme conditions. This
planet has a mass five times that of Earth’s and is in fact the closest
known exoplanet to its host star. Theoretical models suggest that the
planet may have lava or boiling oceans on its surface. The ESO artist
has provided an impression of how it may look like if it were covered by
lava. Image courtesy of ESO/L. Calcada. The original image is available
here.
Washington, D.C.— A new planet-hunting survey has
revealed planetary candidates with orbital periods as short as four
hours and so close to their host stars that they are nearly skimming the
stellar surface. If confirmed, these candidates would be among the
closest planets to their stars discovered so far. Brian Jackson of the
Carnegie Institution for Science’s Department of Terrestrial Magnetism
will present his team’s findings, which are based on data from NASA’s
Kepler mission, at the American Astronomical Society’s Division of
Planetary Sciences meeting.
Most gas giant exoplanets with orbital periods less than or equal to a
few days are unstable. This is due to decay in their orbits caused by
the effects of their star’s proximity. For rocky or icy planets, this
disruption could bring them close enough to the star that the force of
their own gravity can no longer hold them together in the face of the
star’s gravity.
Motivated by these considerations, Jackson’s team conducted a search
for very short-period transiting objects in the publicly available
Kepler dataset. Their preliminary survey revealed about a half dozen
planetary candidates, all with periods less than 12 hours. Even with
masses of only a few times that of Earth, the short periods mean they
might be detectable by currently operating ground-based facilities.
If confirmed, these planets would be among the shortest-period
planets ever discovered, and if common, such planets would be
particularly amenable to discovery by the planned TESS mission, which
will look for, among other things, short-period rocky planets.
In his presentation, Jackson will describe the survey, what has been
learned about the candidates from Kepler data, and the team’s plans for
follow-up observations.
The team includes Carnegie’s Christopher Stark and Alan Boss, as well
as Elisabeth Adams of the Planetary Science Institute, Michael Endl of
the McDonald Observatory, Phil Arras of the University of Virginia, and
Drake Deming of the University of Maryland at College Park.
Caption: Brian Jackson's study focuses on planetary
candidates with orbital periods so close to their host stars that they
are nearly skimming the stellar surface. This artist's conception from
the European Southern Observatory depicts the exoplanet Corot-7b, which
is so close to its Sun-like host star that it must experience extreme
conditions. A larger image and more details are available here.
***
Funding for this work was provided by the Carnegie Institution for Science’s Department of Terrestrial Magnetism.
Source: Carnegie Institution for Science
