Spectroscopic studies of the pulsating sdB binary PG1336-018

V.M. Woolf (1), C.S. Jeffery (1), D. Pollacco (2)

1. Armagh Observatory, College Hill, Armagh, Northern Ireland
2. Queens University Belfast, Belfast, Northern Ireland

We report null results from a series of studies of the pulsating binary
subdwarf B star PG 1336-018. These are presented here so that subsequent
studies might be guided by our experience.

Two attempts were made to detect the spectrum of the
secondary at, respectively, the calcium infrared triplet and
H$\alpha$. In both of these we obtained a series of spectra through
the binary orbit, but could find no evidence of spectral lines from
the low-luminosity companion in either the integrated spectrum or in a
cross-correlation analysis of the individual spectra.

3.4-hours of high time resolution spectroscopy were obtained at the 
Anglo-Australian Telescope in an effort to measure the
radial velocities due to the non-radial pulsations of the sdB star.
We again measured velocities using spectral cross correlation. The binary
orbital radial velocity is apparent in the velocity curve, but the
pulsational radial velocities cannot be detected in a power
spectrum.  To resolve the velocity variation due to stellar pulsation
it will be necessary to obtain spectra over a longer time period,
preferably with higher signal to noise.