2014 programme

Sun 20th
13:30-14:00
New York

Delta Scuti–type pulsating stars in eclipsing binary systems

Margaret Streamer

Variable Stars South, Canberra Astronomical Society, Astonomical Society of New South Wales

Isolated δ Scuti-type (DSCT) stars show pulsations with low amplitude (less than 0.1 magnitudes) and short periods (less than 3 hours).

They can also be found in binary systems which can be detached or semi-detached. In the detached systems, the δ Scuti component is a typical DSCT star. However in more evolved, semi-detached systems the pulsator is accreting mass from the other component in the binary system.

Although not particularly common, several δ Scuti-type pulsating components in short-period (<5days) eclipsing systems have been discovered as part of the Southern Eclipsing Binaries Programme of Variable Stars South. The light curves of each system are all slightly different but are characterised by a very shallow secondary eclipse compared to the primary eclipse. The longer-period magnitude changes due to the eclipses can be separated from the much shorter pulsation periods, thus allowing the determination of the frequency and amplitude of the pulsations.

Margaret Streamer

Margaret is a keen amateur with an interest in technical astronomy – thanks to attendance at past NACAA’s. Her main interest is variable stars with a focus on eclipsing binary systems, though she also does the occasional lunar graze.