28 April 2005

Speaker: Jaymie M. Matthews (University of British Columbia)

Title: Probing Pulsations and Planets with a Humble Space Telescope: Results of Ultraprecise Photometry from Canada's MOST Microsat

Abstract: Viewing the Universe in new ways has always yielded surprising discoveries. Astronomers are accustomed to extending the limits of wavelength coverage, light-gathering power, and angular resolution. The MOST (Microvariability and Oscillations of STars) mission - a suitcase-sized microsatellite housing an optical photometer of small (15-cm) aperture which deliberately blurs its stellar images for stability - forges its advances in totally different regions of parameter space. MOST is the only existing observatory on Earth or in space which can monitor stars several times per minute with almost no interruptions for weeks at a time, reaching photometric precisions of a few micromagnitudes (ppm). These demonstrated levels of time sampling and ultraprecise photometry enable the MOST Science Team to explore with unprecedented sensitivity acoustic (p-mode) oscillations and surface convection in other stars, reflected light from giant close-in exoplanets, and other phenomena associated with stellar variability. I will summarise the scientific results from MOST as it approaches its second anniversary in orbit. Those results include: (1) the first photometric detection of solar-like oscillations in a star other than the Sun, eta Boo; (2) a surprising null detection of oscillations in Procyon, and a direct comparison of MOST photometry to 3-D hydrodynamical simulations of granulation in that star; (3) real-time observations of differential rotation in a young active sun-like star, kappa 1 Ceti; (4) studies of pulsation in massive Oe stars and hot B subdwarfs; and (5) preliminary results on exoplanet systems.

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