講演者: Andrzej Czechowski Spectroscopic observations show that the disk of beta-Pictoris includes, besides the dust component, also a gaseous one. A number of gas species have been identified both in absorption and emission spectra. We examine the possibility that the observed gas originates from collisional vaporization of the dust in the disk. The main mechanism is the vaporization of larger grains in bound orbits by the small grains ("beta-meteoroids") accelerated away from the star by radiation pressure. We also consider the velocity distribution of the resulting gas and find that some puzzling features of the observed emission spectra (peaks at the Keplerian orbital velocities) do not necessarily indicate that the emitting gas is corotating in bound orbits. |