Dr. Sara Ellison awarded the Rutherford Memorial Medal in Physics by the Royal Society of Canada (September 24, 2014)

This is an official CASCA Press Release.

It is with great pleasure that the Canadian Astronomical Society / Société Canadienne d’Astronomie recognizes and applauds Dr. Sara Ellison of the University of Victoria in Victoria, British Columbia for being awarded the prestigious Rutherford Memorial Medal in Physics by the Royal Society of Canada.

As Canada’s senior National Academy, the RSC exists to promote Canadian research and scholarly accomplishment in both of Canada’s official languages, to mentor young scholars and artists, to recognize academic and artistic excellence, and to advise governments, non-governmental organizations, and Canadians generally on matters of public interest (http://rsc-src.ca/en/about-us/our-purpose/mandate-mission-and-vision).

Dr Ellison received her PhD in astronomy from Cambridge University in 2000,  then moved to the European Southern Observatory in Chile as an ESO fellow.  She joined the University of Victoria in 2003, and was promoted to associate professor in 2008 and full professor this year. Amongst other honours, she was given the Annie Jump Cannon award by the American Astronomical Society in 2004. Her research focuses on understanding galaxy evolution through cosmic time.

Contacts:
Leslie Sage
CASCA Press Officer
+1 (301) 675 8957
cascapressofficer@gmail.com

Dr. Christian Marois elected to the College of New Scholars of the Royal Society of Canada (September 17, 2014)

This is an official CASCA Press Release.

It is with great pleasure that the Canadian Astronomical Society / Société Canadienne d’Astronomie recognizes and applauds the election of Dr. Christian Marois of the NRC Herzberg Astronomy and Astrophysics in Victoria, British Columbia to the College of New Scholars of the Royal Society of Canada.

The College of New Scholars, Artists and Scientists is Canada’s first national system of multidisciplinary recognition for the emerging generation of Canadian intellectual leadership (http://rsc-src.ca/en/college-new-scholars-artists-and-scientists ).

Dr Marois received his PhD in astronomy from the Université de Montréal in  2004, then moved to Lawrence Livermore National Laboratory in California as  a post-doc. He joined the Herzberg Institute of Astrophysics in 2008. He was awarded CASCA’s Plaskett Medal in 2005 for the best PhD thesis in astronomy in the preceding year, and the CBC named him their scientist of the year in 2008. His research is focused on the direct imaging of exoplanets.

Contacts:
Leslie Sage
CASCA Press Officer
+1 (301) 675 8957
cascapressofficer@gmail.com

Dr. Harvey Richer is Elected to the Royal Society of Canada (Sept. 16, 2014)

This is an official CASCA Press Release.

It is with great pleasure that the Canadian Astronomical Society / Société Canadienne d’Astronomie recognizes and applauds the election of Dr. Harvey Richer of the University of British Columbia, in Vancouver, British Columbia, to the Royal Society of Canada.

As Canada’s senior National Academy, the RSC exists to promote Canadian research and scholarly accomplishment in both of Canada’s official languages, to mentor young scholars and artists, to recognize academic and artistic excellence, and to advise governments, non-governmental organizations, and Canadians generally on matters of public interest (http://rsc-src.ca/en/about-us/our-purpose/mandate-mission-and-vision).

Harvey received his PhD in astronomy from the University of Rochester in 1970, and moved to UBC the same year. He was the Gemini Scientist for Canada 2000-2003, and has won the Carlyle S. Beals Award from CASCA, the Canada-Fulbright Fellowship in 2005, held the Canada Council Killam Fellowship 2001-2003 and the UBC Killam Fellowship in1991. His current research focuses on the oldest white dwarf stars and what they can tell us about the formation and evolution of stellar systems like globular clusters.

Contacts:
Leslie Sage
CASCA Press Officer
+1 (301) 675 8957

UBC Science Media Contacts
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UBC Science
balma@science.ubc.ca
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Une planète bien curieuse, si loin de son étoile… (13 Mai 2014)

Une équipe internationale dirigée par des chercheurs de l’Université de Montréal a découvert et photographié une nouvelle planète située à 155 années-lumière de notre système solaire.

MONTRÉAL, le 13 mai 2014 – Une planète géante gazeuse vient s’ajouter à la courte liste des exoplanètes découvertes par imagerie directe. Elle se trouve autour de GU Psc, une étoile trois fois moins massive que le Soleil et située dans la constellation des Poissons. L’équipe de recherche internationale dirigée par Marie-Ève Naud, étudiante au doctorat au Département de physique de l’Université de Montréal, a réussi à trouver cette planète en combinant des observations provenant du télescope de l’Observatoire du Mont-Mégantic (OMM), des télescopes Gemini Nord et Sud, du Télescope Canada-France-Hawaii (TCFH), et du télescope Keck.

Une planète distante qui se laisse étudier en détail

GU Psc b est située à environ 2000 fois la distance Terre-Soleil de son étoile, un record parmi les exoplanètes. Étant donné cette distance, il faut environ 80 000 années terrestres pour que GU Psc b fasse une orbite complète autour de son étoile! Les chercheurs ont d’ailleurs profité de la grande distance qui sépare la planète de son étoile afin d’en obtenir des images. En comparant des clichés obtenus dans différentes longueurs d’onde (couleurs) à l’OMM et au TFCH, ils ont pu correctement détecter la planète.

« Les planètes sont beaucoup plus brillantes lorsqu’on les observe dans l’infrarouge plutôt qu’en lumière visible, car leur température de surface est plus basse que celles des étoiles, explique Marie-Ève Naud. C’est ce qui a permis de repérer GU Psc b. »

 

Savoir où regarder!

Si les chercheurs scrutaient les alentours de GU Psc, c’est parce que cette étoile venait tout juste d’être identifiée comme membre du groupe d’étoiles jeunes AB Doradus. Les étoiles jeunes (âgées de seulement 100 millions d’années) sont des cibles de premier choix pour la détection de planètes par imagerie car les planètes en orbite autour d’elles sont encore en train de se refroidir, et sont donc plus lumineuses. Cela ne veut pas dire pour autant que des planètes semblables à GU Psc b existent en grand nombre, comme le précise Étienne Artigau, codirecteur de thèse de Marie-Ève Naud et astrophysicien à l’Université de Montréal : « Nous avons observé plus de 90 étoiles et n’avons trouvé qu’une seule planète. Il s’agit donc d’une curiosité astronomique! »

L’observation d’une planète ne permet pas de déterminer directement sa masse. Les chercheurs utilisent donc des modèles théoriques d’évolution planétaire pour établir ses caractéristiques. Le spectre de la lumière de la planète, obtenu au télescope Gemini Nord, à Hawaii, a pu être comparé à des modèles pour montrer que celle-ci aurait une température aux alentours de 800 °C. Connaissant l’âge de GU Psc par son appartenance à AB Doradus, l’équipe a pu déterminer sa masse, comprise entre 9 et 13 fois celle de Jupiter.

Les astrophysiciens ont bon espoir de détecter au cours des prochaines années des planètes semblables à GU Psc b, mais beaucoup plus près de leur étoile, grâce, entre autres, à de nouveaux instruments comme GPI (Gemini Planet Imager), récemment installé sur Gemini Sud, au Chili. La proximité de ces planètes avec leur étoile rendra toutefois leur observation beaucoup plus ardue. GU Psc b sera donc un modèle permettant de mieux comprendre ces objets.

« GU Psc b est un véritable cadeau de la nature. La grande distance qui la sépare de son étoile rend possible son étude approfondie avec une variété d’instruments, ce qui permettra de mieux comprendre les exoplanètes géantes, en général », précise René Doyon, codirecteur de thèse de Marie-Ève Naud et directeur de l’OMM.

L’équipe a entamé un projet afin d’observer plusieurs centaines d’étoiles et de détecter des planètes plus légères que GU Psc b sur des orbites comparables. La découverte de GU Psc b, un objet certes rare, permet de prendre conscience de la distance importante qui peut exister entre certaines planètes et leur étoile, ce qui laisse entrevoir la possibilité de chercher des planètes avec des caméras infrarouges performantes à partir de télescopes beaucoup plus petits, tels que celui de l’Observatoire du Mont-Mégantic. Les chercheurs espèrent aussi en savoir davantage sur l’abondance de tels objets d’ici quelques années, notamment grâce aux instruments GPI, SPIRou pour le TCFH et FGS/NIRISS pour le télescope spatial Webb.

À propos de cette étude

L’article Discovery of a Wide Planetary-Mass Companion to the Young M3 Star GU Psc sera publié dans la revue The Astrophysical Journal, le 20 mai 2014. L’équipe, menée par Marie-Ève Naud, étudiante au doctorat au Département de physique de l’Université de Montréal et membre du CRAQ, était principalement constituée d’étudiants et de chercheurs de l’UdeM, notamment Étienne Artigau, Lison Malo, Loïc Albert, René Doyon, David Lafrenière, Jonathan Gagné et Anne Boucher. Des collaborateurs d’autres établissements ont aussi participé, notamment Didier Saumon, du Los Alamos National Laboratory au Nouveau-Mexique, Caroline Morley, de UC Santa Cruz en Californie, France Allard et Derek Homeier, du Centre de Recherche Astrophysique de Lyon, en France, de même que Christopher Gelino et Charles Beichman, de Caltech, en Californie. Cette étude a été possible grâce aux financements du Fonds de recherche du Québec – Nature et technologies et du Conseil de recherches en sciences naturelles et en génie du Canada.

Consultez l’article de l’Astrophysical Journal.

À propos du CRAQ

Le Centre de recherche en astrophysique du Québec est un partenariat entre l’Université de Montréal, l’Université McGill et l’Université Laval. Il regroupe tous les chercheurs dans le domaine de l’astronomie et de l’astrophysique de ces trois établissements, et aussi des collaborateurs de l’Université Bishop’s, de l’Agence spatiale canadienne, du Cégep de Sherbrooke et d’entreprises privées (Photon etc., ABB Bomem, Nüvü Caméras). Le CRAQ est l’un des regroupements stratégiques financés par Le Fonds de recherche du Québec – Nature et technologies (FQRNT). Le CRAQ constitue un pôle unique au Québec de chercheurs en astrophysique, dont les expertises variées et complémentaires, axées sur l’excellence, permettent l’innovation, la créativité et la compétitivité dans plusieurs domaines scientifiques, offrant ainsi aux étudiants de cycles supérieurs un éventail important de sujets en recherche fondamentale et appliquée.

Renseignements supplémentaires

Sources :

Marie-Ève Naud
CRAQ – Université de Montréal
514 343-6111, poste 3797
naud@astro.umontreal.ca
 

René Doyon
Directeur de l’Observatoire du Mont-Mégantic
Professeur titulaire au Département de physique
CRAQ – Université de Montréal
514 343-6111, poste 3204
doyon@astro.umontreal.ca

Renseignements :

Olivier Hernandez, Ph. D.
CRAQ – Université de Montréal / Responsable des relations médias
514 343-6111, poste 4681 | olivier@astro.umontreal.ca | @OMM_Officiel  | @CRAQ_Officiel

Milky Way amidst a ‘Council of Giants’ (March 11, 2014)

We live in a galaxy known as the Milky Way – a vast conglomeration of 300 billion stars, planets whizzing around them, and clouds of gas and dust floating in between.

Though it has long been known that the Milky Way and its orbiting companion Andromeda are the dominant members of a small group of galaxies, the Local Group, which is about 3 million light years across, much less was known about our immediate neighbourhood in the universe.

Now, a new paper by York University Physics & Astronomy Professor Marshall McCall, published today in the Monthly Notices of the Royal Astronomical Society, maps out bright galaxies within 35-million light years of the Earth, offering up an expanded picture of what lies beyond our doorstep.

“All bright galaxies within 20 million light years, including us, are organized in a ‘Local Sheet’ 34-million light years across and only 1.5-million light years thick,” says McCall. “The Milky Way and Andromeda are encircled by twelve large galaxies arranged in a ring about 24-million light years across – this ‘Council of Giants’ stands in gravitational judgment of the Local Group by restricting its range of influence.”

McCall says twelve of the fourteen giants in the Local Sheet, including the Milky Way and Andromeda, are “spiral galaxies” which have highly flattened disks in which stars are forming. The remaining two are more puffy “elliptical galaxies”, whose stellar bulks were laid down long ago. Intriguingly, the two ellipticals sit on opposite sides of the Council. Winds expelled in the earliest phases of their development might have shepherded gas towards the Local Group, thereby helping to build the disks of the Milky Way and Andromeda.

McCall also examined how galaxies in the Council are spinning. He comments: “Thinking of a galaxy as a screw in a piece of wood, the direction of spin can be described as the direction the screw would move (in or out) if it were turned the same way as the galaxy rotates. Unexpectedly, the spin directions of Council giants are arranged around a small circle on the sky. This unusual alignment might have been set up by gravitational torques imposed by the Milky Way and Andromeda when the universe was smaller.”

The boundary defined by the Council has led to insights about the conditions which led to the formation of the Milky Way. Most important, only a very small enhancement in the density of matter in the universe appears to have been required to produce the Local Group. To arrive at such an orderly arrangement as the Local Sheet and its Council, it seems that nearby galaxies must have developed within a pre-existing sheet-like foundation comprised primarily of dark matter.

“Recent surveys of the more distant universe have revealed that galaxies lie in sheets and filaments with large regions of empty space called voids in between,” says McCall. “The geometry is like that of a sponge. What the new map reveals is that structure akin to that seen on large scales extends down to the smallest.”

Original Press Release from the Royal Astronomical Society, on behalf of York University, Toronto, Canada (RAS PR 14/16)

Media Contacts

Robin Heron
Media Relations
York University
Canada
Tel: +1 416 736 2100 x22097
rheron@yorku.ca

Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7734 3307 x214
Mob: +44 (0)794 124 8035
rm@ras.org.uk

Images and animations

Image 1: https://www.ras.org.uk/images/stories/press/Local%20sheet%20topview.jpg
A diagram showing the brightest galaxies within 20 million light years of the Milky Way, as seen from above. The largest galaxies, here shown in yellow at different points around the dotted line, make up the ‘Council of Giants’. Credit: Marshall McCall / York University

Image 2: https://www.ras.org.uk/images/stories/press/Local%20sheet%20sideview.jpg
A diagram showing the brightest galaxies within 20 million light years of the Milky Way, this time viewed from the side. Credit: Marshall McCall / York University

Movie with sound: http://youtube/VzL7xGzfNlU (channel YorkU Astronomer)
An animation that illustrates the positions of the nearby galaxies, including those in the ‘Council of Giants’, in three dimensions. Credit: Marshall McCall / York University

Movie with no sound: https://www.ras.org.uk/images/stories/press/council_of_giants_nosound_v2.mp4
An animation that illustrates the positions of the nearby galaxies, including those in the ‘Council of Giants’, in three dimensions. Credit: Marshall McCall / York University

Further information

The new work appears in “A Council of Giants”, M. L. McCall, Monthly Notices of the Royal Astronomical Society, Oxford University Press, in press. A copy of the paper is available from http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stu199

‘Death Stars’ in Orion Blast Planets before They Even Form (March 13, 2014)

The Orion Nebula is home to hundreds of young stars and even younger protostars known as proplyds. Many of these nascent systems will go on to develop planets, while others will have their planet-forming dust and gas blasted away by the fierce ultraviolet radiation emitted by massive O-type stars that lurk nearby.

A team of astronomers from Canada and the United States has used the Atacama Large Millimeter/submillimeter Array (ALMA) to study the often deadly relationship between highly luminous O-type stars and nearby protostars in the Orion Nebula. Their data reveal that protostars within 0.1 light-years (about 600 billion miles) of an O-type star are doomed to have their cocoons of dust and gas stripped away in just a few millions years, much faster than planets are able to form.

“O-type stars, which are really monsters compared to our Sun, emit tremendous amounts of ultraviolet radiation and this can play havoc during the development of young planetary systems,” remarked Rita Mann, an astronomer with the National Research Council of Canada in Victoria, and lead author on a paper in the Astrophysical Journal. “Using ALMA, we looked at dozens of embryonic stars with planet-forming potential and, for the first time, found clear indications where protoplanetary disks simply vanished under the intense glow of a neighboring massive star.”

Many, if not all, Sun-like stars are born in crowded stellar nurseries similar to the Orion Nebula. Over the course of just a few million years, grains of dust and reservoirs of gas combine into larger, denser bodies. Left relatively undisturbed, these systems will eventually evolve into fully fledged star systems, with planets – large and small – and ultimately drift away to become part of the galactic stellar population.

Astronomers believe that massive yet short-lived stars in and around large interstellar clouds are essential for this ongoing process of star formation. At the end of their lives, massive stars explode as supernovas, seeding the surrounding area with dust and heavy elements that will get taken up in the next generation of stars. These explosions also provide the kick necessary to initiate a new round of star and planet formation. But while they still shine bright, these larger stars can be downright deadly to planets if an embryonic solar systems strays too close.

“Massive stars are hot and hundreds of times more luminous than our Sun,” said James Di Francesco, also with the National Research Council of Canada. “Their energetic photons can quickly deplete a nearby protoplanetary disk by heating up its gas, breaking it up, and sweeping it away.”

Earlier observations with the Hubble Space Telescope revealed striking images proplyds in Orion. Many had taken on tear-drop shapes, with their dust and gas trailing away from a nearby massive star. These optical images, however, couldn’t reveal anything about the amount of dust that was present or how the dust and gas concentrations changed in relation to massive stars.

The new ALMA observations detected these and other never-before-imaged proplyds, essentially doubling the number of protoplanetary disks discovered in that region. ALMA also could see past their surface appearance, peering deep inside to actually measure how much mass was in the proplyds.
Combining these studies with previous observations from the Submillimeter Array (SMA) in Hawai‛i, the researchers found that any protostar within the extreme-UV envelope of a massive star would have much of its disk of material destroyed in very short order. Proplyds in these close-in regions retained only a fraction (one half or less) of the mass necessary to create one Jupiter-sized planet. Beyond the 0.1 light-year radius, in the far-UV dominated region, the researchers observed a wide range of disk masses containing anywhere for one to 80 times the mass of Jupiter. This is similar to the amount of dust found in low-mass star forming regions.

“Taken together, our investigations with ALMA suggest that extreme UV regions are not just inhospitable, but they’re downright hazardous for planet formation. With enough distance, however, it’s possible to find a much more congenial environment,” said Mann. “This work is really the tip of the iceberg of what will come out of ALMA; we hope to eventually learn how common solar systems like our own are.”

Other researchers involved in this project include Doug Johnstone, National Research Council of Canada; Sean M. Andrews, Harvard-Smithsonian Center for Astrophysics; Jonathan P. Williams, University of Hawai‛i; John Bally, University of Colorado; Luca Ricci, California Institute of Technology; A. Meredith Hughes, Wesleyan University, and Brenda C. Matthews, National Research Council of Canada.

Official press release: https://public.nrao.edu/news/pressreleases/death-stars-in-orion