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Time-resolved high-resolution spectroscopy
of the pulsating
sdB star QQ Vir (PG1325+101)
John Telting et al., Shanghai, July 2009
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Seismology of stars; need for accurate mode identification
Seismologogy probes the inner
structure of stars, and can/may provide clues to the general
evolution of subdwarf OB stars
Observations reveal eigenvalues
(pulsation frequencies), and eigenfunctions (pulsation modes), and
basic stellar parameters
Asteroseismological analyses
benefit from observed frequencies and observed
mode-identifications to conclusively constrain the internal structure.
It was suggested to provide observational constraints on the pulsation
modes to aid the asteroseismological analyses (e.g. Charpinet et al
2005; PG1219). Van Grootel (2008), Hu (2008) further discuss the importance
of observational mode-identification for seismology of sdB stars.
Complementary observational
techniques to identify pulsation modes:
-
photometric/spectroscopic amplitude ratios ⇒ probes temperature,
gravity, radial velocity ⇒ gives L
(Baran et al. later today: QQ Vir)
- line-profile variability ⇒ probes 3D velocity field ⇒
gives L and |M|