A Hydrodynamical Model for Infalling Evaporating Bodies in the β Pictoris Circumstellar Disk

✍ Scribed by Hervé Beust; Michel Tagger

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 807 KB
• Volume: 106
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.1993.1157

✦ Synopsis

The temporal spectroscopic variations monitored since 1985 toward (\beta) Pictoris ( (\beta) Pic) in both visible and UV lines have been formerly interpreted as the result of the vaporization, in the vicinity of the star, of small cometary-sized bodies falling toward the star. This scenario received further confirmation by extensive modeling in past years. However, the mere presence of Al III ions near (\boldsymbol{\beta}) (\mathrm{Pic}) is still a puzzling problem, since the star itself is unable to photoionize Al II. We present here a new model, where the problem of the dynamics of metallic ions in a cometary-like cloud released by an infalling body is treated hydrodynamically. The surface limiting the ionic clouds is calculated as a bow shock, thus giving access to physical parameters. The first results of this model confirm those obtained from the previous simulations. Once applied to the dynamics of Al II ions, it reveals that for bodies sufficiently close to the star, the heat generated by compression and collisions within the shock surface of the Al II cloud is high enough to explain the collisional formation of Al III ions, thus giving for the first time a clue for solving this important problem. 1993 Academic Press, lnc.