The first three years of the outburst and light-echo evolution of V838 Mon and the nature of its progenitor

V838 Mon has undergone one of the most mysterious stellar outbursts on record, with (a) a large amplitude (Delta B ~ 10 mag) and multi-maxima photometric pattern, (b) a cool spectral type at maximum becoming cooler and cooler with time during the descent, until it reached the never-seen-before realm of L-type supergiants, never passing through optically thin or nebular stages, (c) the development of a spectacular, monotonically expanding light-echo in the circumstellar material, and (d) the identification of a massive and young B3V companion, unaffected by the outburst. In this talk we review the photometric and spectroscopic evolution during the first three full years of outburst, the light-echo development and infer the nature of the progenitor, which was brighter and hotter in quiescence than the B3V companion and with an inferred ZAMS mass of about 65 Msun.Comment: to appear in the Proceedings of the Colloquium "Interacting Binaries: Accretion, Evolution and Outcome", held in Cefalu' (Sicily) July 4-10, 2004, L.A. Antonelli et al. eds., American Institute of Physics Conf. Proc. series, in press. 6 pages, 4 figure

Writing instrument interfaces with xf/tktcl

Tcl is an embedded control language written in C, running primarily under Unix and with an interpreted C look-and-feel. Tk is an X11 toolkit based on tcl. Xf is an application builder for tk. The entire package is public domain and available from sprite.berkeley.edu. This paper discusses the use of tk to develop a user interface for OSIRIS, an infrared camera/spectrograph now operational on the OSU Perkins 1.8m telescope. The good and bad features of the development process are described

Activity of the Polar AM Her (RX J1816.2+4952): A Short Review

We show that AM Her displays the transitions between the high and low states with an intermittently existing dominant cycle with length between 400 and 800 days. Moreover, these transitions accumulate in clusters, which produces an additional long cycle after smoothing; a single isolated short episode of the low state does not suggest a break of this cycle. The seasons of existence of the cycle can be controlled by the lifetime of the active regions (e.g. prominences, spots) on the donor. In some high-state episodes, a higher luminosity of the bremsstrahlung emission is not accompanied by a higher optical (cyclotron+stream) emission. Part of the bremsstrahlung emission can be buried in some episodes. Changes of the structure of the accretion region(s) are necessary to explain the variations of the optical and X-ray activity in the high-state episodes of AM Her