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.

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

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.

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

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.

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

UBC Science Media Contacts
Chris Balma
UBC Science
604.202.5047 (c)

Silvia Moreno-Garcia
Coordinator, Communications

Next-Generation Thirty Meter Telescope Begins Construction in Hawaii

Following the approval of a sublease on July 25 by the Hawaii Board of Land and Natural Resources, the Thirty Meter Telescope (TMT) announces the beginning of the construction phase on Hawaii Island and around the world throughout the TMT international partnership. Contingent on that decision, the TMT International Observatory (TIO) Board of Directors, the project’s new governing body, recently approved the initial phase of construction, with activities near the summit of Mauna Kea scheduled to start later this year.

Kahu Ku Mauna and the Mauna Kea Management Board reviewed, and the University of Hawaii Board of Regents recently approved, the proposed TMT sublease. The final approval from the Board of Land and Natural Resources—the last step in the sublease process—allows TMT to begin on-site construction on Mauna Kea, home to many of the world’s premier observatories.

“It has been an amazing journey for TMT, from idea to shovel-ready project,” said Henry Yang, TIO Board Chair and Chancellor of the University of California Santa Barbara. “We are grateful to the Gordon and Betty Moore Foundation, the Hawaiian government, its citizens, and our project partners in bringing this important astronomical science effort to fruition. It is also my rewarding experience to work with so many community friends, University of Hawaii colleagues, and officials on both the Big Island and Oahu in this journey.”

The Rise of a New Observatory – Activities Around the World

The TMT project was initiated a decade ago by the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology (Caltech), and the University of California as the TMT Observatory Corporation. Now, as the TMT International Observatory (TIO)—founded as a nonprofit limited liability company on May 6, 2014 —the project has the official green light to begin constructing a powerful next-generation telescope.

The TIO founding members are Caltech, the National Astronomical Observatories of the Chinese Academy of Sciences, the National Institutes of Natural Sciences in Japan, and the University of California. India, an associate, is expected to become a full member later this year. Canada is also an associate and aiming to join as a full member in 2015.

Initial construction activities in Hawaii will include grading the site in preparation for future building work, enabling a site dedication ceremony in October. TMT is committed to work within a plan for responsible development on Mauna Kea created by the Office of Mauna Kea Management.

“TMT has worked for many years to design an unprecedented telescope, but also to work with the community to incorporate respect for Mauna Kea in our stewardship,” said Gary Sanders, Project Manager for TMT. “It is an honor and a privilege to now begin building our next-generation observatory in so special a place.”

Other work has already been proceeding off-site and will continue now apace.

“Design of the fully articulated main science steering mirror system in the telescope, as well as development of the lasers, laser guide star systems and other high-tech components, is proceeding in China,” said Yan Jun, Director General of the National Astronomical Observatories of China.

“Japan has seen to the production of over 60 mirror blanks made out of special zero-expansion glass that does not alter its shape with temperature changes. The blanks will be highly polished for use in the telescope’s 30-meter diameter primary mirror. The final design of the telescope structure itself is nearing completion,” said Masanori Iye, TMT International Observatory Board Vice Chair and TMT Japan Representative for the National Astronomical Observatory of Japan.

In Canada, the TMT adaptive optics facility is in final design. Ernie Seaquist, Executive Director of the ACURA, added, “The TMT enclosure design is complete and the enclosure is now ready for construction by a Canadian industrial firm.”

“Prototyping of TMT’s primary mirror assemblies and the building of mirror actuators, edge sensors, and support systems is ongoing in India,” noted Eswar Reddy, Program Director of the India TMT Coordination Centre.

Three “first-light” instruments are also under development with major contributions from all of the TMT partners.

The Path to Construction

The announcement of an imminent start to on-site work, where all of these initial developments will come together, is welcome news to scientists worldwide.

“The start of construction means that TMT is becoming real, and that’s exciting news for astronomers,” said Catherine Pilachowski, an astronomer at Indiana University in Bloomington, Ind., and an observer representing the United States astronomical community at TMT board meetings. “The science TMT will do is breathtaking, and will engage all astronomers in the adventure of new frontiers.”

The advancement of TMT to this stage of imminent on-site construction has been made possible by the support of the Gordon and Betty Moore Foundation. The foundation has spent $141 million to date to fund the design, development, and construction phases of TMT.

“I’d like to extend my deepest gratitude to the Gordon and Betty Moore Foundation and all of our partners and supporters,” said Edward Stone, the Morrisroe Professor of Physics at Caltech and the new Executive Director of TIO. “We are looking forward to starting construction this year and moving ahead.”

A Boost for Hawaii

The start of TMT on-site construction will directly benefit the local Hawaiian community. TMT will now make its first annual contribution to The Hawaii Island New Knowledge (THINK) Fund, a program that promotes science, technology, engineering, and math education across grades K-12, secondary, and post-secondary education. Over the life of the TMT lease on Mauna Kea, TMT will give $1 million per year to the THINK Fund.

In the construction sector, TMT will create about 300 full-time construction jobs. TMT has committed to the hiring of union workers for these positions. Looking further ahead, during operations, TMT will have a staff of about 120-140, which will be drawn as much as possible from Hawaii Island’s available labor pool. A workforce pipeline program in the meantime will also educate and train island residents for jobs with TMT, as well as other observatories and high-tech industries.

“The start of construction of TMT is great news for Hawaii Island residents,” said Sandra Dawson, TMT’s Manager of Hawaii Community Affairs. “We are proud to be a good citizen of the community as we all work toward building a revolutionary astronomical instrument.”

Original press release: http://www.tmt.org/news-center/next-generation-thirty-meter-telescope-begins-construction-hawaii

CFHT Uncovers Large Number of Dark Matter Peaks Using Gravitational Lensing (July 15, 2014).

A number of studies have shown that Dark Matter is the principal mass component of the Universe making up about 80% of the mass budget. The most direct technique to reveal the Dark Matter distribution is by using the gravitational lensing technique. Indeed, following Einstein’s theory of Gravitation, we know that a mass concentration will deform locally the Space-Time and the observed shapes of distant galaxies seen through the such concentration will be deflected and distorted. By measuring the exact shapes of millions of these distant galaxies we can then map accurately the mass distribution in the Universe, and identify the mass peaks tracing mass concentration along their line of sight. Importantly, the number of mass peaks as a function of the mass peak significance encodes important information on the cosmological world model. In particular this distribution is sensitive to the nature of Gravitational force at large scales as well as the geometry of the Universe. Measuring mass peaks is thus one of the most attractive way to probe the relative importance and nature of Dark Matter and Dark Energy, measure the evolution the Universe and predict its fate.

In a new publication of the Monthly Notice of Royal Astronomical Society, an international team, comprising researchers from Swiss, France, Brazil, Canada, and Germany present the first detailed analysis of the weak lensing peaks. This work is considered as a milestone, given the possible importance of the weak lensing peaks for cosmology. Because mass peaks are identified in two–dimensional dark matter maps directly, they can provide constraints that are free from potential selection effects and biases involved in identifying and measuring the masses of galaxy clusters. In fact a small fraction of the max peaks are just mass concentration excess along the line of sight, and not genuine massive clusters.

To detect the weak lensing mass peaks, the research team used the Canada-France-Hawaii Telescope Stripe 82 Survey (CS82 in short), still one of the largest weak lensing survey yet. The Survey covers ~170 square degrees of the Stripe 82 of the Sloan Digital Sky Survey (SDSS), an equatorial region of the South Galactic Cap that has been extensively studied by the SDSS project. With the precise shape measurement for more than four million faint distant galaxies, a dark matter mass map was generated. Huan Yuan Shan, the lead author of this publication explains that: “By studying the mass peaks in the map, we found that the abundance of mass peaks detected in CS82 is consistent with predictions from a ΛCDM cosmological model. This result confirms that the dark matter distribution from weak lensing measurement can be used as a cosmological probe”.

Jean-Paul Kneib, co-author of the publication explains that: “This work opens a new window to constrain cosmology with weak gravitational lensing. We can not only reveal where the dark matter is located using space-time distortion, but also use the distributions of mass peaks to better constrain and understand our Universe”.

Huan Yuan Shan, adds that: “Because of their large number, the small mass peaks in the Dark Matter maps contain more resolving power than the most massive peaks to constrain cosmological models”. As a cosmological probe, the weak lensing mass peak abundance is very complementary to the other cosmology probes, such as the study of the Cosmological Microwave Background (CMB), the study of distant SuperNovae, the measure of the Baryonic Accoustic Oscillation and the cosmic shear.

The abundance of mass peaks in the Dark Matter mass map confirms the theories of structure formation. In the near future, with the up-coming weak lensing surveys (to be conducted with the DES survey, LSST and Euclid), by precisely counting the peaks of dark matter mass maps, we will be able to set constrains on the nature of Dark Matter and Dark Energy.

About the CFHT Stripe 82 survey:

The CFHT Stripe 82 (CS82) collaboration comprises scientists from the following institutions: University of British Columbia (Canada), Laboratoire d’Astrophysique de Marseille (France), Brazilian Center for Physics Research (Brazil), École Polytechnique Fédérale de Lausanne (Switzerland), Institute for the Physics and Mathematics of the Universe (Japan), Universität Bonn (Germany), Institut d’Astrophysique de Paris (France), Valongo Observatory/Federal University of Rio de Janeiro (Brazil), Instituto de Astronomia, Geofísica e Ciências Atmosféricas – USP (Brazil), Instituto de Física – UFRGS (Brazil), Observatório Nacional (Brazil), Universitá deli studi di Ferrara (Italy), University of Hertfordshire (UK), University of Oxford (UK), University College London (UK), University of Waterloo (Canada), Leiden Observatory (Netherlands), Lawrence Berkeley National Laboratory (USA), University of California Berkeley (USA), Stanford (USA).

The CS82 survey is based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. The Brazilian partnership on CFHT is managed by the Laboratório Nacional de Astrofísica (LNA). We thank the support of the Laboratório Interinstitucional de e-Astronomia (LIneA). We thank the CFHTLensS team through the expertise they built in analysing CFHT/Megacam weak lensing data.

ADS link to the paper

Contact information:
Dr. HuanYuan Shan
Affiliation: EPFL, Switzerland
Phone number: +41 22 379 2427

Prof. Jean-Paul Kneib.
Affiliation: EPFL, Switzerland
Phone number +33 695 795 392

Prof. Martin Makler.
Affiliation: CBPF, Brazil
Phone number +55 21 2141 7191

Prof. Ludovic van Waerbeke
Affiliation: UBC, Canada
Phone number +1 604 822 5515

Dr. Eric Jullo.
Affiliation: LAM, France
Phone number +33 491 05 59 51

Dr. Daniel Devost
Director of Science Operations
Phone: (808)885-3163

TMT Exhibits a Next-Generation Telescope Mirror Assembly in Canada (June 9, 2014)

The Thirty Meter Telescope (TMT) project will unveil a polished mirror assembly – a key piece of astronomy’s next-generation telescope – at the 2014 annual meeting of the Canadian Astronomical Society (CASCA). The assembly will be unveiled at a reception at 5:30pm EDT, Monday, June 9 at the Hotel Chateau Laurier, in Quebec City, Canada.

The assembly is a demonstration model of just one of the 492 mirror segments that will ultimately comprise TMT’s giant 30-meter primary mirror. TMT is a revolutionary telescope slated to begin operations in Hawaii in the 2020s.

“We are delighted that the first presentation of these sophisticated mirror assemblies is happening right here at CASCA 2014,” said Laura Ferrarese, CASCA president. “For the past decade, the Thirty Meter Telescope has been the top priority for the Canadian astronomical community, and we have worked tirelessly with our international partners to design this marvel of engineering. The science TMT will deliver will be transformative for astronomy, in Canada and worldwide.”

The polished mirror assembly displayed at CASCA, though a prototype, has nearly all of the features of a production version. The hexagonal 1.44-meter diameter mirror is made of a 45-millimeter-thick ClearCeram glass produced by the Japanese company OHARA and procured by TMT’s Canadian partners. The glass has “zero expansion” properties, meaning it retains its precise figure irrespective of changes in temperature. Within the mirror’s support assembly, 21 actuators can fine-tune the mirror’s shape for optimal telescope performance. The prototype assembly weighs about 220 kilograms.

“Given the extensive involvement by Canadian scientists and engineers in the technology development of TMT, it is fitting to offer the world a first look at a polished mirror assembly—the application of all that hard work—right here in Quebec City,” said Ernie Seaquist, executive director of the Association of Canadian Universities for Research in Astronomy (ACURA). An organization of 20 universities dedicated to the advancement of university research in astronomy and astrophysics in Canada, ACURA is an associate of the TMT project and one of its original members.

The production segments will include an extremely reflective mirror coating, and edge sensors that sense the height and tilt of neighboring mirror segments, allowing for precise positioning of each segment relative to the other segments. Together, 492 of these mirrors will work together as a single optical surface comprising TMT’s 30-meter-diameter primary mirror.

“Being able to showcase this polished mirror assembly to the scientific community and the general public is very rewarding,” said Eric Williams, the Optics Group leader for TMT. Williams has been working on designing and testing elements of the assembly for nine years.

TMT is identified as the highest priority project by CASCA in “Unveiling the Cosmos: A Vision for Canadian Astronomy, Report of the Long Range Plan 2010 Panel”. This plan, released in 2011, is the result of a detailed survey of the challenges and opportunities over the 2010-20 decade.

Through ACURA universities with support from the Federal Granting Councils, the National Research Council of Canada, and provincial funding, the Canadian astronomical community has contributed important work to TMT over the last decade in two key development areas.

Canada has been designing the telescope facility’s large aerodynamic enclosure. The innovative enclosure design features a circular opening that minimizes the wind-induced vibrations of the telescope structure while optimizing air-flow around the building to reduce distortion of the light collected by the telescope’s giant mirror. The contractor for the enclosure work is Dynamic Structures Ltd., based in Port Coquitlam, British Columbia, whose parent holding company is the Canadian firm Empire Industries Ltd.

Another major Canadian initiative has been the development of TMT’s “adaptive optics” system, called the Narrow Field Infrared Adaptive Optics System (NFIRAOS). Adaptive optics removes the blurring effects of the Earth’s atmosphere, greatly increasing the acuity of astronomical images and allowing astronomers to study very faint and distant objects in the universe.

To date, Canada has invested more than $30 million in TMT. The TMT project plans to begin construction later this year. As an Associate in the TMT International Observatory, Canada continues to be engaged in the project.

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

Laura Ferrarese
CASCA President

TMT Contact:
Gordon K. Squires
TMT Communications Lead
+1 (626) 216 4257

More information about TMT:

Odd planet, so far from its star… (May 13, 2014)

An international team led by Université de Montréal researchers has discovered and photographed a new planet 155 light years from our solar system.

MONTRÉAL, May 13, 2014 – 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 the Gemini Observatories, 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 Observatory 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 Gemini South 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 GPI instruments, 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.

Additional information




Marie-Ève Naud
CRAQ – Université de Montréal
514 343-6111, ext 3797

René Doyon
Director, Observatoire du Mont-Mégantic
Professor, Department of Physics
CRAQ – Université de Montréal
514 343-6111, ext 3204


Olivier Hernandez, Ph. D.
CRAQ – Université de Montréal / Head of Media Relations
514 343-6111, ext 4681 | olivier@astro.umontreal.ca | @OMM_Officiel  | @CRAQ_Officiel

‘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

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
Tel: +1 416 736 2100 x22097

Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7734 3307 x214
Mob: +44 (0)794 124 8035

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

Phosphorus in the Young Supernova Remnant Cassiopeia A

An international team of astronomers, including Prof. Dae-Sik Moon at the University of Toronto, has measured for the first time the abundance of phosphorus created in a supernova explosion.

The team’s observational results show that phosphorus is 100 times more abundant in the remains left over from a supernova than elsewhere in the galaxy, confirming that massive exploding stars are the crucibles in which the element is created.

Astronomers have measured the abundance of carbon, nitrogen, oxygen, and sulphur in supernovae remnants before. But this is the first measurement of the relatively scarce phosphorus.

“These five elements are essential to life and can only be created in massive stars,” says Moon, co-author of the paper being published in the journal Science on December 13, 2013.

“They are scattered throughout our galaxy when the star explodes, and they become part of other stars, planets and ultimately, humans,” says Moon. “This is why Carl Sagan said we are made of ‘starstuff’. Now we have measured how much of this particular element of starstuff is created in supernovae.”

Moon is in the Department of Astronomy & Astrophysics and the Dunlap Institute for Astronomy & Astrophysics at the U of T. Other members of the research team include lead author Bon-Chul Koo, Yong Hyun Lee and Sung-Chul Yoon of Seoul National University in Korea, and John Raymond of the Harvard-Smithsonian Center for Astrophysics.

The observations were of the remnant of a supernova believed to have been observed over 300 years ago. Called Cassiopeia A (Cas A), it lies at a distance of about 11,000 light-years.

Astronomers believe the original star was between 15 and 25 times the mass of the Sun. When a star of such mass runs out of the hydrogen that it burns to produce energy, the core of the star goes through a sequence of collapses, synthesizing heavier elements with each collapse.

Moon and his colleagues made their observations using the TripleSpec near-infrared spectrograph on the Palomar 5-metre Hale telescope. The instrument—which Moon co-developed—allowed the team to directly compare the spectral lines of phosphorus and iron and, thus, calculate the abundance ratio of the two.

Carl Sagan knew that this starstuff is the “…the calcium in our teeth, the iron in our blood.” Now, Moon and his colleagues have directly measured the starstuff that is the phosphorus in our DNA and our bones.


Prof. Dae-Sik Moon
Department of Astronomy & Astrophysics
Dunlap Institute for Astronomy & Astrophysics
University of Toronto
e: moon@astro.utoronto.ca
p: 416-978-6566

Chris Sasaki
Public Information Officer
Dunlap Institute for Astronomy & Astrophysics
University of Toronto
e: csasaki@dunlap.utoronto.ca
p: 416-978-6613

The Dunlap Institute for Astronomy & Astrophysics, University of Toronto, continues the legacy of the David Dunlap Observatory: by developing innovative astronomical instrumentation, including for the largest, most advanced telescopes in the world; by training the next generation of astronomers; and by fostering public engagement in science. The research of its faculty and postdoctoral fellows includes the discovery of exoplanets, the formation of stars, galactic nuclei, the evolution and nature of galaxies, the early Universe and the Cosmic Microwave Background, and the Search for Extra-terrestrial Intelligence (SETI).

Special Instructions: For image for splash page, visit http://dunlap.utoronto.ca/for-the-media/downloads/ Password: CasA