Image 1. The planet GU Psc b and its star GU Psc composed of visible and
infrared images from the Gemini South telescope and an infrared image
from the CFHT. Because infrared light is invisible to the naked eye,
astronomers use a colour code in which infrared light is represented by
the colour red. GU Psc b is brighter in infrared than in other filters,
which is why it appears red in this image. download JPG 1.2MB
Image 2. Artist's view of the planet GU Psc b and its star GU Psc. (© Lucas Granito. download JPG 434 KB
Image 3. Constellation of Pisces (© Stellarium)
Joint press release from Université de Montréal, Observatoire du Mont-Mégantic, Centre for Research in Astrophysics of Québec, and Gemini Observatory
An international team led by Université de Montréal researchers has
discovered and photographed a new planet 155 light years from our solar
system.
A gas giant has been added to the short list of exoplanets discovered
through direct imaging. It is located around GU Psc, a star three times
less massive than the Sun and located in the constellation Pisces. The
international research team, led by Marie-Ève Naud, a PhD student in the
Department of Physics at the Université de Montréal, was able to find
this planet by combining observations from the Gemini Observatory, the
Observatoire Mont-Mégantic (OMM), the Canada-France-Hawaii Telescope
(CFHT) and the W.M. Keck Observatory.
A distant planet that can be studied in detail
GU Psc b is around 2,000 times the Earth-Sun distance from its star, a
record among exoplanets. Given this distance, it takes approximately
80,000 Earth years for GU Psc b to make a complete orbit around its
star! The researchers also took advantage of the large distance between
the planet and its star to obtain images. By comparing images obtained
in different wavelengths (colours) from the OMM and CFHT, they were able
to correctly detect the planet.
"Planets are much brighter when viewed in infrared rather than visible
light, because their surface temperature is lower compared to other
stars," says Naud. "This allowed us to indentify GU Psc b."
Knowing where to look
The researchers were looking around GU Psc because the star had just
been identified as a member of the young star group AB Doradus. Young
stars (only 100 million years old) are prime targets for planetary
detection through imaging because the planets around them are still
cooling and are therefore brighter. This does not mean that planets
similar to GU Psc b exist in large numbers, as noted by by Étiene
Artigau, co-supervisor of Naud's thesis and astrophysicist at the
Université de Montréal. "We observed more than 90 stars and found only
one planet, so this is truly an astronomical oddity!"
Observing a planet does not directly allow determining its mass.
Instead, researchers use theoretical models of planetary evolution to
determine its characteristics. The light spectrum of GU Psc b obtained
from the Gemini North Telescope in Hawaii was compared to such models to
show that it has a temperature of around 800°C. Knowing the age of GU
Psc due to its location in AB Doradus, the team was able to determine
its mass, which is 9-13 times that of Jupiter.
In the coming years, the astrophysicists hope to detect planets that are
similar to GU Psc but much closer to their stars, thanks, among other
things, to new instruments such as the GPI (Gemini Planet Imager)
recently installed on the Gemini South telescope in Chile. The
proximity of these planets to their stars will make them much more
difficult to observe. GU Psc b is therefore a model for better
understanding these objects.
"GU Psc b is a true gift of nature. The large distance that separates it
from its star allows it to be studied in depth with a variety of
instruments, which will provide a better understanding of giant
exoplanets in general," says René Doyon, co-supervisor of Naud's thesis
and OMM Director.
The team has started a project to observe several hundred stars and
detect planets lighter than GU Psc b with similar orbits. The discovery
of GU Psc, a rare object indeed, raises awareness of the significant
distance that can exist between planets and their stars, opening the
possibility of searching for planets with powerful infrared cameras
using much smaller telescopes such at the one at the Observatoire du
Mont-Mégantic. The researchers also hope to learn more about the
abundance of such objects in the next few years, in particular, using
the Gemini Planet Imager, the CFHT's SPIRou, and the James Webb Space Telescope's FGS/NIRISS.
About the study
The article Discovery of a Wide Planetary-Mass Companion to the Young M3
Star GU Psc will be published in The Astrophysical Journal on May 20,
2014. The team, led by Marie-Ève Naud, doctoral student at the
Department of Physics of the Université de Montréal and member of the
CRAQ, consisted mainly of UdeM students and researchers, including
Étienne Artigau, Lison Malo, Loïc Albert, René Doyon, David Lafrenière,
Jonathan Gagné, and Anne Boucher. Collaborators from other institutions
also participated, including Didier Saumon, Los Alamos National
Laboratory, New Mexico; Caroline Morley, UC Santa Cruz, California;
France Allard and Derek Homeier, Centre for Astrophysical Research,
Lyon, France; and Christopher Gelino and Charles Beichman, Caltech,
California. The study was made possible with funding from the Fonds de
recherche du Québec – Nature et technologies and the Natural Sciences
and Engineering Research Council of Canada. See the article in The Astrophysical Journal
About the CRAQ
The Centre for Research in Astrophysics of Québec is a partnership
between the Université de Montréal, McGill University, and the
Université Laval. The CRAQ brings together all researchers working in
the field of astronomy and astrophysics of these three institutions, as
well as other collaborators from Bishop's University, the Canadian Space
Agency, the Cégep de Sherbrooke, and the private sector (Photon etc.,
ABB Bomem Inc., Nüvü Caméras). The CRAQ is funded through the program
Regroupements stratégiques of the Fonds de recherche du Québec – Nature
et technologies (FRQ-NT). The CRAQ constitutes a unique grouping of
researchers in astrophysics in Québec bent on excellence and whose
varying and complementary fields of expertise allows them to be
innovative, creative and competitive in several scientific fields, thus
offering graduate students a wide variety of subjects in both
fundamental and applied fields of research.
Science Contacts:
- Marie-Ève Naud
CRAQ – Université de Montréal
514 343-6111, ext 3797
naud@astro.umontreal.ca
-
René Doyon
Director, Observatoire du Mont-Mégantic
Professor, Department of Physics
CRAQ – Université de Montréal
514 343-6111, ext 3204
doyon@astro.umontreal.ca
Media Contacts:
-
Olivier Hernandez, Ph. D.
CRAQ – Université de Montréal / Head of Media Relations
olivier@astro.umontreal.ca
514 343-6111, ext 4681
- Peter Michaud
Gemini Observatory Public Information and Outreach Office
Hilo, Hawai‘i
pmichaud@gemini.edu
Desk: (808) 974-2510
Cell: (808) 936-6643
Source: Gemini Observatory
