On the Vega Debris Discs Dust Grains: Short-lived or Long-Iived?
Through Spitzer Space Telescopes observations, Su et al. (2005) show that the Vega debris disc is dominated by grains which are small enough to be blown out by radiation pressure. This implies the lifetime of Vega debris discs grains is relatively short, about 1000 year8, and a continuous dust production is necessary to maintain the observed debris disc. However, Krivov et al. (2006)s theoretical calculations show that the Vega debris disc is dominated by 10 μm grains, which would be in bound orbits and thus long-lived, provided that the disc is in a steady 8tate. In order to solve the above contradiction, through dynamical simulations, we determine the grains orbital evolutions and density profiles and seek a model of size distribution which can reproduce the observed surface brightness. Our results show that a self-consistent dynamical model with a 1/R disc density profile can be constructed when the grains have a power-law size distribution. Moreover, both types of models, dominated by short-lived and long-lived grains, are consistent with the observational data.
circumstellar matter planetary systems stellar dynamics
Ing-Guey Jiang Li-Chin Yeh
Department of Physics and Institute of Astronomy,National Tsing-Hua University,Hsin-Chu,Taiwan Department of Applied Mathematics,National Hsinchu University of Education Hsin-Chu,Taiwan
国际会议
The 10th Asian-Pacific Regional International Astronomical Union Meeting(第十届亚洲及太平洋地区天文学大会 APRIM)
昆明
英文
44-46
2008-08-03（万方平台首次上网日期，不代表论文的发表时间）