Wood, Brian E.

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Institute: CASA
First Coauthor: Margarita Karovska
Institute: Harvard-Smithsonian Center for Astrophysics
Second Coauthor: Warren Hack
Institute: STSCI
Subject Area: Binary Stars: Interacting
Waveband: Ultraviolet
Technique: Spectroscopy
Presentation: Poster Display
Title: Detection of H₂ Emission from Mira B with the HST
Abstract: We present results from our HST/STIS observations of Mira's companion (Mira B) carried out in July-August 1999. Mira B is a compact object surrounded by an accretion disk at a distance of at least 70 AU from Mira. The high resolution ultraviolet spectra of Mira B obtained using STIS show that the spectral signatures of the accretion disk have changed dramatically when compared to HST observations obtained only four years earlier. The STIS UV spectrum detected numerous, narrow H₂ lines fluoresced by H I Ly$\alpha$, which have never been seen previously in spectra of the Mira AB system. Furthermore, the continuum fluxes in the Mira B spectra are much lower than observed before, at least an order of magnitude when compared to the 1995 HST/FOC objective prism spectra, and lower than ever observed by IUE. These significant changes in the spectral distribution of Mira B might be due to disk instabilities induced by substantial inhomogeneity in Mira A's massive wind.