AAS 204th Meeting, June 2004
Session 85 What's New with Old Variable Stars?
Special Session, Thursday, June 3, 2004, 10:00-11:30am, 710/712

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[85.02] Mira Variable Stars: Spectroscopic and Photometric Monitoring of this broad class of Long Term Variable and Highly Evolved Stars.

D.E. Mais (Department of Astronomy, Palomar College, San Marcos, CA), R.E. Stencel (Department of Physics and Astronomy, University of Denver, Denver, CO), D. Richards (Wessex Astronomy Society, Dorset, UK)

Mira variable stars are a broad class long period variable stars, which encompass spectroscopic classes of type M, S and C. Recently, evidence has accumulated to suggest that Mira variables may go through flare up stages which result in brightening on the order of several tenths of a magnitude or more and may last hours to days in length (Schaefer, B., 1991, Maffei, P., and Tosti, G., 1995 and de Laverny, P., et. al., 1998). Very little is known about these events, indeed it is not clear that these events are real. If they are real events, the spectroscopic changes, which occur during these flare-up episodes, remain relatively unexplored. This project was initiated in order to monitor a group of program stars of these classes in the V and R photometric bands in the hopes of “catching” some of these stars during one of these flare ups, thus offering confirmation to their reality and to be able to conduct spectral analysis of the flare-ups in real time and compare these spectra to the non-flare spectra. Monitoring of a group of these stars was carried out using equipment readily available to amateurs, both in the way of telescopes, CCD cameras and software. Commercially available software was used to control telescope pointing and image acquisition with different filters. In addition, in order to make analysis as real time as possible, scripts for reduction of images were created to automatically perform astrometric solutions and determine magnitudes of the variables from standard stars in the field. During the course of the past year, nearly 98 program stars have been monitored to address the potential flare up episodes. These include 25 M-type, 16-S type and 57 C-type Mira’s. Precision of these measurements are in the milli-magnitude regime. This talk will describe the results obtained so far.


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