Seeking Cosmic Evolution in a Grain of Dust
7 Jan 2003
(Source: University of Toronto)
Extrasolar meteors hint at distant planet formation Radar telecopes could trace dust grains back to neighbouring solar systems by Nicolle Wahl
University of Toronto
January 6, 2003
University of Toronto astronomers say that detecting microscopic meteors from other solar systems could provide clues about the formation of planets like Earth.
Dust streams from our sun's stellar neighbours consist of tiny grains of pulverized rock ejected from a disk of dust and debris that commonly surrounds young stars, says Joseph Weingartner, a post-doctoral fellow at U of T's Canadian Institute for Theoretical Astrophysics. According to Professor Norman Murray, associate director of CITA and co-author of the study, "if we can detect these grains and trace them back to the star system that they came from, we'd have very good evidence of planet formation going on in that system." Weingartner presented the study Jan. 6 at the American Astronomical Society meeting in Seattle, Wash.
The tiny grains are created by collisions of large objects such as boulders and asteroids during or slightly after the process of planet formation, he explains. The collisions create a disk of particulate grains (each grain is about 100 times smaller than a grain of sand).
Some of these grains are then ejected from a disk after "slingshotting" around a planet. Weingartner says the speeds of the grains entering our solar system can range from a few kilometers to 100 kilometres per second. If the grains are travelling at high velocities, researchers know that they originate from outside our solar system.
Weingartner and Murray propose that future radar telescope facilities that can examine roughly one million square kilometers of space be used to detect dust streams coming from nearby stars. By detecting the speed and direction of grains when they hit the Earth's atmosphere, scientists could potentially trace the path of the tiny grains back to star systems where planet formation may be occurring.
"In astronomy, if you want information, you always rely on radiation like visible light or infrared light," says Weingartner. "You can think of these radar facilities as a different type of telescope - a telescope for collecting dust rather than a telescope for collecting light."
Among the star systems whose dust streams could be studied is beta Pictoris, a 10-to-20 million-year-old star located roughly 63 light years from the sun. Weingartner and Murray estimate that in the dust disk around beta Pictoris, the mass of the particles with a radius of one centimeter or smaller is about 19 times the mass of the Moon.
"We have a real opportunity to open a new window on these kinds of systems," says Weingartner. He and Murray say that their study is a first step in a new approach to astronomical research, and note that further studies will require the construction of large radar telescope facilities with expanded sky coverage.
The study was funded by the Natural Sciences and Engineering Research Council of Canada.
Nicolle Wahl is a news services officer with the department of public affairs.
CITA ph: (416) 978-8497
Norman Murray, CITA
ph: (416) 978-1778
(Available Jan. 7)
U of T Public Affairs
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