HST/FOS Discovery of CVs and (?) in the Globular NGC6397

Session 85 - Cataclysmic Variables and Accretion Disks.
Oral session, Wednesday, January 15
Harbour A,

[85.01] HST/FOS Discovery of CVs and (?) in the Globular NGC6397

J. E. Grindlay (CfA), A. Cool (SFSU), C. Bailyn (Yale), H. Cohn, P. Lugger (Indiana U.)

The number and nature of cataclysmic variables (CVs) in globular clusters is one of the premier questions in current studies of globulars with HST and ROSAT (as well as future AXAF studies). CVs trace the production of compact binaries and white dwarfs in globulars and their role in the dynamical evolution of cluster cores. With HST imaging studies of the post core collapse globular NGC 6397, we found (Cool et al 1995, ApJ, 439, 695) the first emission line (H\alpha) CV candidates which we confirmed (Grindlay et al 1995, ApJ, 455, L47) with HST/FOS spectra as being almost certainly CVs and possibly magnetic (DQ Her type) CVs. We have now obtained (Cycle 6) FOS spectra (450-680nm) of two additional candidates. One is almost certainly a CV, with strong Balmer and HeI emission lines (and weak HeII), whereas the nature of the other object is puzzling. Results will be presented and implications for the total number and nature of CVs in globulars will be discussed.

The author(s) of this abstract have provided an email address for comments about the abstract: josh@cfa.harvard.edu

Program listing for Wednesday