HST observations of the gas around \bp : additional evidence for infalling evaporating bodies

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Session 41 -- Circumstellar Disks
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[41.08] HST observations of the gas around \bp : additional evidence for infalling evaporating bodies

P. D. Feldman, J. B. McPhate, H. W. Moos (JHU), H. Beust, R. Ferlet, A. Lecavelier, A. Vidal-Madjar (IAP, Paris), A.-M. Lagrange-Henri (Obs. de Grenoble), J. J. Lissauer (SUNY, Stony Brook), M. Deleuil, C. Gry (LAS, Marseille), L. M. Hobbs (Yerkes Obs.), M. A. McGrath (STScI)

Spectroscopic studies of the circumstellar (CS) gas around \bp\ since 1984 have led to the detection of strong short-term variations in the CS lines of ionized species (see for instance Ferlet \etal , 1987, A\&A 185, 267, and Lagrange \etal , 1992, A\&A 264, 637 for the visible data and Lagrange \etal , 1988, A\&A 190, 275 for the UV data), tentatively attributed to evaporation from solid, cometary-like bodies falling on the star. Detailed simulations of such a scenario have been developed and reproduce the medium resolution UV as well as the high resolution visible data available so far (Beust \etal , 1990, A\&A 236, 202; 1991, A\&A, 241, 488; Beust and Tagger, 1993, Icarus, in press). In this poster, we will present high resolution UV spectra obtained in December 1992 with the Hubble Space Telescope GHRS. These data (Vidal-Madjar \etal , 1993, A\&A, to be submitted) enable us to confirm the presence of very ionized species around \bp\ such as C\,{\sc iv}, already proposed by Deleuil \etal\ (1993, A\&A 267, 187) from IUE data, but also to detect unambiguously the molecular species CO. The variable parts of other CS lines (e.g., Fe\,{\sc ii}, Mg\,{\sc ii}, Al\,{\sc iii}), observed with unprecedented high resolution and high signal-to-noise, also bring strong support to the evaporating infalling body scenario.

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