Angular size measurements of 19 Mira variable stars

Session 60 - Stellar Astrophysics I.
Oral session, Tuesday, January 16
Salon del Rey North, Hilton

[60.03] Angular size measurements of 19 Mira variable stars

G. T. van Belle, H. M. Dyck (U. Wyoming), J. A. Benson (USNO), M. G. Lacasse (Harvard U.)

We present angular size measurements of 19 oxygen-rich Mira variable stars made at IOTA (IR Optical Telescope Array). These observations are part of a long term observational program to directly ascertain the oscillation mode of these variables. From the data, the Rosseland mean diameter is calculated using the Mira atmosphere models of Scholz amp; Takeda (1987 Aamp;A, 186, 200). Estimates of bolometric flux for these stars, combined with the diameter measurements, are used to calculate effective temperatures, T_EFF. The stars observed were similar in nature and represent an extensive sample of points along a single phase cycle of Mira variables; the phase dependence of T_EFF is shown to follow simple expectations. Using distance estimates for these stars, linear sizes are also calculated, and the phase dependence of radius is discussed.

Program listing for Tuesday