Untitled Essay Research Paper BETA PICTORIS PLANETS — страница 2
- Просмотров 146
- Скачиваний 5
- Размер файла 16 Кб
planet accretion (2). This retention of nearly coplanar orbits in the Beta Pictoris disk is a qualitative argument in support of its being a relatively young system (2). Some astronomers believe that we are witnessing planet formation in the process. Lagage and Pantin found that the inner region of the disk surrounding Beta Pictoris is clear of dust, a prime indicator that there is evidence of one or more planetary bodies (3). The depletion zone extends to about 15 AU from the star, about the same size as our solar system; and has an average particle density only one tenth of the area just outside this zone (3). Lagage and Pantin believe that the inner zone may have been swept clean by the gravitational pull of a planet orbiting around Beta Pictoris (3). A planet would gravitationally deflect the particles out of the inner zone. This planet, which is only believed to exist, may also be deflecting comets into the star, as indicated by the presence of highly variable absorption lines in the spectrum of Beta Pictoris (3). The infrared image by Lagage and Pantin also provide information that the edge-on disk is not symmetrical around the star (3). This suggests a more intimate relationship between the asymmetry and the properties of the inner disk. As the orbital timescale for particles is relatively short (less than 100 years), one would expect that the irregularities in the disk would have been smoothed out by now (3). Unless, there was something stirring it up, such as a planet (3). If there is a planet orbiting Beta Pictoris, its orbit is probably eccentric, as are most of the planetary orbits in our solar system (4). A planet with even a moderately eccentric orbit would generate the asymmetry that is been noted in the dust disk surrounding Beat Pictoris (4). The Hubble Space Telescope, using the high-resolution spectrograph, found that the disk surrounding beta Pictoris consists of two parts: an outer ring of small, solid particles, and an inner ring of diffuse gas within a few hundred miles of the star (5). Albert Boggess, an astronomer at NASA’s Goddard Space Flight Center, suspects that the gas comes from the ring of solid particles (5). If he is correct, then the gas may be a sign that planets are being born there. The gas could be a result from the collision of solid particles in the outer ring accreting into planets that are still too small to see because of the brightness of the star itself (5). During the collisions some of the particles would be vaporized and drawn toward the star. The planets in our own solar system are believed to have formed through countless numbers of such collisions (5). Boggess also believes that Beta Pictoris is very similar to a very early phase of our own solar system (5). Additional evidence, from the Hubble, also suggests that Beta Pictoris might be following in our footsteps. The gaseous inner ring appears to contain clumps of material spiraling toward the star (5). These clumps may be comets, diverted from the normal paths by close calls with protoplanets (5). This also fits with current ideas about the evolution of our own solar system. Gases from comet impacts may have been the creating factor of the Earth’s atmosphere and oceans (5). Wetherill argues that life on Earth is reliant upon the existence of Jupiter and Saturn, because they cleansed our Solar System of most of its planetesimals (comets) that, otherwise, would be striking the Earth (6). In order for a planet to survive long enough for life to begin, it is necessary for the existence of gas giants (Jupiter and Saturn) to get rid of the hazardous comets. No one person can say for sure whether there are planets in the Beta Pictoris System, or not. However, it is definitely a possibility. There is a circumstellar disk surrounding Beta Pictoris. It is a highly flattened disk, as was the disk that once surrounded the Sun. The disk contains the necessary elements for planet formation. The star is a young one. The inner zone of the disk is clear. All of these things point to the almost probable formation of planets. Richard Terrile, from the Jet Propulsion Laboratory, says, “It’s hard not to form planets from material like this (7).” To answer whether or not there could be life on one of these planets, is not easy to say. No one can really even speculate. I, believe that it is possible, if all the variables come together in just the right way. I am not ‘earthnocentric’ to assume that the earth is the only planet in the Universe that can sustain life. Whether or not a planet in the Beta Pictoris system has what it takes, who knows, we can only wait and watch. BIBLIOGRAPHY(1) Moons And Planets, third edition; William K.