star system forms. In that case, even if GU Psc
b is in all likelihood below 13 Jupiter masses,
and thus of “planetary mass,” we can wonder
if it should be called a “planet.”
At this point, it’s hard to exclude other exotic
scenarios, such as the capture by the current
host star of a free-floating planet, formed
on its own, or ejected from another star system. The host star and its companion could
also have been ejected from the system of
a more massive star. On various fronts, this
object raises many questions.
A Key to Understanding
We expect to find more of these peculiar
planets in the future. Their unique characteristics will allow us to not only study them in
great detail but also improve our knowledge
of giant exoplanets and other exotic planetary systems.
Marie-Eve Naud is a Ph.D. student at Université
de Montréal. She can be reached at:
[email protected]
Étienne Artigau is a research scientist at Université de Montréal. He can be reached at:
[email protected]
The large distance between GU Psc b and its
host star is an important attribute and a major advantage when it comes to acquiring a
detailed characterization of the companion
object. This planetary-mass companion can
be studied like few other exoplanets, because the task requires no AO systems or sophisticated high-contrast imaging methods.
We can expect this object to help by constraining models of cool brown dwarfs and
exoplanets in this age range. It can also constitute a reference in the understanding of
other closer-in planets we should find with
instruments like GPI.
The discovery of GU Psc b makes it clear that
massive planets very distant from their host
stars do exist, even around low-mass stars.
Although they are probably rare, they can
be discovered quite easily using “standard”
direct imaging techniques.
Indeed, Frédérique Baron, a Ph.D. student at
Université de Montréal under the direction
of David Lafrenière and Étienne Artigau, will
expand the present survey with deep z- and
J-band imaging at Gemini and CFHT, targeting a sample of 300 stars. This survey will be
sensitive to objects down to 1-2 times the
mass of Jupiter at separations ranging from
200 to 5000 AU.
January 2015
2014 Year in Review
GeminiFocus
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