Ref: SCART-2019-0111

Eclipse mapping of Algol-type systems with oscillating δ Scuti type components

Lampens, Patricia ; Vermeylen, Lore ; De Cat, Peter ; Van Cauteren, Paul

in press to Bulletin de la Société Royale des Sciences de Liège (2019)

Abstract: The oscillating Algol-type (oEA) stars are the former secondaries of evolved, semi-detached eclipsing binaries which are (still) undergoing mass transfer and form a newly detected class of pulsators close to the main sequence. Their unique feature consists of mass accretion onto the atmosphere of the pulsating star. Mass accretion affects the mass, radius, density as well as the star’s evolution (depending on the accretion rate). Such stars are therefore very attractive targets for asteroseismic studies. A new method for mode identification of pulsating components in eclipsing binaries was suggested by Nather & Robinson (1974). The method uses the primary eclipse event as a spatial filter to resolve the pulsations across the stellar surface of the pulsator. It is based on the fact that, during an eclipse of the pulsating component, the occulting star acts as a screen with a timely variable shape. During an eclipse, depending on the spatial structure of modes represented by the wave numbers (l,m), different shapes of the pulsation amplitude and phase variations are observed. A comparison between the modelled and the observed patterns (in amplitude and phase) provides the correct mode identification. The method needs a geometrical model, the pulsation frequencies and the light curves as input. The geometrical model can be obtained from a simultaneous modelling of the light (photometry) and radial velocity curves (e.g. as acquired with the HERMES spectrograph). The pulsation frequencies are obtained from subtracting a binary model from the original light curves followed by a frequency analysis of the residuals. We will identify and illustrate systems where observations with a fast CCD camera equipping the 3.6-m DOT telescope could deliver the data needed for the application of the eclipse mapping method.

Keyword(s): Stars: eclipsing binary – Stars: fundamental parameters – Stars: accretion – Stars: Delta Scuti
Note: In Proceedings of the Second Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop, October 2018, held at ROB, Uccle, Belgium

The record appears in these collections:
Royal Observatory of Belgium > Astronomy & Astrophysics
Science Articles > Peer Reviewed Articles

 Record created 2019-01-29, last modified 2019-02-08