Eclipsing binary systems with pulsating components. Gamarova A. Yu., Mkrtichian D.E., Hatzes A.P., Lehmann H. Liege, 2002

Eclipsing binaries with pulsating components (EBPC) Detached systems: Typical objects: AI Hya, MM Cas, RS Cha etc. (See Lampens & Boffin, 2000, ASP vol 210) Eclipsing binaries with b Cep stars; Eclipsing binaries with RR Lyr stars; Eclipsing binaries with Cepheids (See Szatmary K. 1990, JAAVSO, vol 19 ) Semi-detached Algol-type systems: oscillating EA (oEA) (See Mkrtichian et al, 2002, ASP vol.259) Known objects: AB Cas, RZ Cas, Y Cam, AS Eri, R CMa, TW Dra, AB Per, RX Hya

Parameters of known oEA: Name Sp. type Porb, d Ppuls,min AB Cas A3 V+K0 IV 1.3668783 83.93 RZ Cas 1.1953 22.43, 25.44 Y Cam A7 V+K1 IV 3.3055 95.74, 78.77, 97.17, 81.22 R CMa F1 V+G2-K2 IV 1.1359 68.5 TW Dra A6 V+K0 IV 2.8069 80 AS Eri A3 V+K0 III 2.6642 24.39, 23.01, 23.34 RX Hya A8 V+K5 2.2816 74.26 AB Per A5 V+G9 IV 7.16028 282.02

The description of oEA group: Evolution: low-mass progenitors of EBS  rapid mass transfer stage rapid evolution into the d Scu,  Boo ... instability strip  slow mass-transfer/accretion stage, evolution along the MS and & pulsations Features: Mass accretion and pulsations , Multiperiodicity (RZ Cas, AS Eri, Y Cam) the shortest known pulsation periods ford Scu–type pulsators are presented (RZ Cas, AS Eri) – high overtone modes; SMT RMT MS

The description of oEA group: Features: orbital modulation of pulsation RV amplitude (RZ Cas, top graph) – screening and attenuation of NRP by inhomogeneous circumbinary envelope & accretion stream rapid changes (during several months) of the pattern of pulsation spectrum (RZ Cas); Anomalous Schlesinger-Rossiter effect (RZ Cas) (Lehmann& Mkrtichian, 2002) Expected Features: Dependence of (dP/dt 1/P) on the accretion rate Influence of rapid mass accretion episodes on pulsation properties and on mode selection mechanism f=0.1 f=0.9

Advantages presented by EBPC: Asteroseismology: The possibility of the precise determination of parameters (masses, radii, effective temperatures); The higher probability of the detection of the sectorial NRP modes; The possibility of mode identification during primary eclipse (the method of spatial filtration); The possibility of use of the circum-binary envelope as a spatial filter. Evolution of eclipsing binaries: The possibility of the precise determination of the asynchronism; The possibility of the precise estimation of the accretion rate and the status on a slow mass-transfer stage (i.e. the age of the system); The possibility of the investigation of the gas envelope properties basing on the inspection of pulsations at different orbital phases.

Mode identification in the oEA AB Cas: Considered pulsation characteristics: Gain factor is the ratio of the observed pulsation amplitudes during the eclipse of pulsating component to the amplitude outside the eclipse: Pulsational phase shift : tmax - the time moment of observed maximum; t0 - predicted by the pulsation ephemeris time of maximum; Ppuls - the observed pulsation period.

Mode identification in the oEA AB Cas:

Prospects for future COROT investigation: Pulsation mode spectra and doing seismology Estimation of the accretion driven photometric noise Hypothesis of synchronization & asynchronity in binary systems

Short summary on the EB in the COROT FOV: Why are these objects suitable for COROT observations? Situated in the possible COROT FOV; The range of magnitudes matches with the range chosen for the COROT transit search; COROT will provide the sufficient accuracy and time coverage for investigation of this type of pulsation variability and mode identifiction; What is known about binaries in the COROT FOV? Faint objects  poorly investigated; No spectral types & effective temeratures are known; No orbital elements are available; No detections of pulsations!!! What do we need to know for application of mode identification techniques and seismology? Spectral types & effective temperatures; Orbital parameters

The prospects for ground-based support: Spectral type classification & effective temperature determination: TLS 2.0m, Calar-Alto, ESO Photometric observations for the determination of the orbital elements and preliminary search for and study pulsations: Euro-Asian (Spain-Ukraine-Kazakhstan-Uzbekistan-South Korea) Network of Observatories.