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Much Ado About HD141569
Notre Dame - Jul 08, 2002 Research by two University of Notre Dame astronomers may shed new light on how planets are formed. Terrence W. Rettig, professor of physics, and graduate student Sean Brittain report their findings in last Thursday's edition of the scientific journal Nature. Even though an Earth-like planet never has been detected outside the solar system, the formation process for these smaller planets is fairly well understood. Observations of infrared and radio emission from dust in space have revealed the presence of protoplanetary disks where dust grains likely accumulate to form rocky planets like Earth. It's a mystery, however, as to how gas giant planets, such as Jupiter and Saturn, form from the remaining primordial hydrogen and helium gas in the disk. The time scale as to how and when this occurs after the formation of Earth-like planets is unknown. Rettig and Brittain have been studying a protoplanetary disk around the star HD141569, located 320 light years from Earth. Particularly intriguing is the fact that they have found emission of gaseous H3+ ions coming from the region around the star. The only previous detection of H3+ emission of this type was in the upper atmospheres of Jupiter, Saturn, Uranus and Neptune. Rettig and Brittain cautiously point out that the detection of H3+ emission may indicate the existence of a forming gas giant planet, or shocked hydrogen gas at the inner edge of the disk. Higher resolution observations are needed to determine if the detection indicates the existence of a large gaseous protoplanet that may eventually form a Jupiter-like planet. However, the prospect is intriguing because this would be the first direct detection of light from an extrasolar planet or protoplanet. Even if future work shows the H3+ originates from the inner disk, the results will provide astronomers important information on how the material surrounding the star evolves chemically. Also, of the 20 stars observed by Rettig and Brittain, H3+ emission was only detected from the more evolved disk around HD141569. Related Links Dept of Physics University of Notre Dame SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express
Sun-Like Star, Dust Eclipse Offers Clues to Origins of Our Solar System
Middletown - Jun 25, 2002Astronomers say they discovered that a sun-like star is being eclipsed in a way never before seen -- not by another star, planet or moon, but by dust grains, rocks and maybe even asteroids orbiting it in a clumpy circumstellar disk. |
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