Gilles Fontaine died on Friday the 1st of November, 2019.
Gilles Fontaine was born in Lévis, Québec, on August 13, 1948. As a youth, he developed a passion for ice hockey, a love of music and parties, and a deep interest in science, all of which remained with him throughout his life. He received a B.Sc. from the Université Laval in 1969 and joined the Department of Physics and Astronomy at the University of Rochester that fall. Initially planning to do graduate work in quantum optics, he instead switched to theoretical astrophysics, receiving his doctorate in 1974 for a thesis entitled “Outer Layers of White Dwarf Stars.” He extended his expertise into observational astronomy during a postdoctoral position at the University of Western Ontario.
In 1977, Gilles returned to Québec with an appointment in the Département de Physique at the Université de Montréal, where he remained for the rest of his productive career. He became a tenured member of the faculty in 1980. In 1981, he was joined at the university by another white-dwarf astrophysicist, François Wesemael. They established a world-renowned research team that rapidly attracted a group of very capable students — many of whom subsequently went on to productive and distinguished careers themselves — and which became an internationally recognized center in the field of white-dwarf research. Gilles made exceptional contributions to the field by training great young scientists, and he encouraged many students to pursue postgraduate education. He was an incredible teacher and a great communicator.
In 1982, Gilles partnered in a search for rapid pulsations that had been predicted to exist in DB (helium-atmosphere) white dwarfs. He and his colleague verified this theoretical prediction observationally, and according to one reliable source, “Much beer was drunk on the mountain that night!” Their discovery made headlines around the world.
Gilles was also one of the pioneers who first used white dwarfs as cosmochronometers to measure the age of our Milky Way Galaxy. In 1987, he and his collaborators accomplished this feat by determining the time required for the faintest white dwarfs to cool to their lowest observed luminosities.
Gilles also became a true leader in the field of asteroseismology, the unique method by which we can examine the internal structures of stars by using observations and numerical modeling to analyze their multiple oscillation modes. In 1990, he and his colleagues published the first asteroseismological results from the Whole Earth Telescope — a collaborative effort involving observatories from around the world to enable continuous high-speed photometric observations of rapidly varying objects like pulsating white dwarfs. As one wit quipped, “The sun never rises on the Whole Earth Telescope!”
In 1996, Fontaine’s group predicted that rapid pulsations should also occur in the degenerate stars known as hot subdwarfs, and in 1997 pulsations were discovered in the sdB star EC 14026. Gilles continued to be active in teaching and research until shortly before his death. One of his last publications reported the observational confirmation of the half-century-old prediction of core crystallization in white dwarfs, an effort led by a former student from his group, utilizing Gaia data for white dwarfs within 100 pc from the sun.
Gilles was internationally respected for the exceptional quality of his research in stellar astrophysics, especially for his studies of the final phases of stellar evolution (white dwarfs and hot subdwarfs, the final products of stellar evolution for most stars). In particular, he made major contributions to the equation of state for white dwarfs and to investigations of pulsating compact stars.
In 1986, Gilles received the E. W. R. Steacie Memorial Research Fellowship, the first of his many prizes and awards. Among other awards he received for his pioneering theoretical and observational work, Gilles was named a Fellow of the Royal Society of Canada in 1992. He received the 1999 Prix Marie-Victorin, one of 14 prizes awarded annually by the Government of Québec, was awarded the 2000 Carlyle S. Beals Award from the Canadian Astronomical Society, and held the Canada Research Chair in Stellar Astrophysics from 2000 until his death. He was awarded the 2016 Medal for Lifetime Achievement in Physics by the Canadian Association of Physicists. The asteroid 2010 GF153, discovered in April 2010 as part of a deep survey of NASA’s Wide Field Infrared Explorer (WISE) telescope, was renamed (400811) Gillesfontaine in his honor.
In addition to being a prolific and productive scientist, Gilles was also a dedicated and active musician, and for many years he was an avid hockey player. He was an exceptional colleague and a dear friend to all who knew him, and he will be sorely missed.