![]() ![]() “If you don’t get it, there is a large part of the planet’s properties that remains undetermined.” “The mass affects everything on a planetary level,” de Wit says. In addition to a planet’s composition, its mass can provide a glimpse of the planet’s surface and internal activity - such as any plate tectonics, its internal cooling and convection, how it generates magnetic fields, and whether gas escapes from its atmosphere. “With this method, we realized the planetary mass - a key parameter that, if missing, could have prevented us from assessing the habitability of the first potentially habitable Earth-size planet in the next decade - will actually be accessible, together with its atmospheric properties,” says Julien de Wit, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences.ĭe Wit is lead author on a paper published today in the journal Science, with co-author Sara Seager, the Class of 1941 Professor of Physics and Planetary Science. This data has traditionally been used to determine a planet’s size and atmospheric properties, but the MIT team has found a way to interpret it such that it also reveals the planet’s mass. Now scientists at MIT have developed a new technique for determining the mass of exoplanets, using only their transmission spectra - dips in light as a planet passes in front of its star. ![]() But the technique is less successful with smaller planets that orbit much farther from their stars, as Earth does. For very large, Neptune-size planets, or smaller Earth-size planets orbiting very bright stars, radial velocity works relatively well. Radial velocity is the main method scientists use: tiny wobbles in a star’s orbit as it is tugged around by the planet’s gravitational force, from which scientists can derive the planet-to-star mass ratio. To determine if any of these far-off worlds are habitable requires knowing an exoplanet’s mass - which can help tell scientists whether the planet is made of gas or rock and other life-supporting materials.īut current techniques for estimating exoplanetary mass are limited. To date, scientists have confirmed the existence of more than 900 exoplanets circulating outside our solar system. Abstract: The Extremely Large Telescopes currently under construction have a collecting area that is. The delivered image quality approaches Gemini’s diffraction limit, with an average measured full-width at half-maximum (FHWM) of 0.09 arcsecond. ![]() Their Ks measurements of the Galactic globular cluster NGC 1851 are combined with HST photometry and the resulting color-magnitude diagram demonstrates that the ground-based data is of an unprecedented depth and precision for crowded field observations. It also illustrates the remarkable potential of MCAO-equipped Extremely Large Telescopes of the future. Their data present the most accurate and deepest near-infrared photometry from the ground of a crowded field. However, Paolo Turri (University of Victoria, Canada) and colleagues have used the Gemini Multi-conjugate adaptive optics System (GeMS) with the Gemini South Adaptive Optics Imager (GSAOI) to do just that. 30 September 2015: Expecting to resolve stars deep into the crowded field of a globular cluster is a tall order for ground-based telescopes. ![]()
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