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Asteroseismology of Gamma Doradus, Beta Cephei, Delta Scuti and other ‘heat-engine’stars. J ørgen Christensen-Dalsgaard Institut for Fysik og Astronomi, Aarhus Universitet Dansk AsteroSeismologisk Center. Mode excitation or damping. Growth rate: amplitude / exp( h t), with.

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## Asteroseismology of Gamma Doradus, Beta Cephei, Delta Scuti and other ‘heat-engine’stars

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**Asteroseismology of Gamma Doradus, Beta Cephei, Delta Scuti**and other ‘heat-engine’stars Jørgen Christensen-Dalsgaard Institut for Fysik og Astronomi, Aarhus Universitet Dansk AsteroSeismologisk Center**Mode excitation or damping**Growth rate: amplitude / exp(h t), with In nonadiabatic region, d L ' constant**Simplified excitation**(J. P. Cox 1964) Too hot**Simplified excitation**Too cold**Simplified excitation**Just right!!**Note:Decreasing Teff! increasing mb! increasing P**for a given opacity bump Location of instability region**Opacity bumps**Pamyatnykh (1999; Acta Astron. 49, 119)**Petersen diagram (J.O. Petersen 1973; Astron. Astrophys 27,**89) Double-mode Cepheids P0! tdyn / (R3/M)1/2 P0 , P1! R, M???**Old opacity**New (OPAL) opacity Track along instability strip P0! tdyn / (R3/M)1/2**Excitation calculation**Pamyatnykh (1999; Acta Astron. 49, 119)**Work integrals**b Cephei SPB d Scuti**l = 0**l = 1 l = 1 Asteroseismologi of b Ceph stars n Eridani De Ridder et al. (2004; MNRAS 351, 324)**Avoided crossings**Models of n Eridani Pamyatnykh et al. (2004; 350, 1022)**Excitation**d Scuti b Cephei Pamyatnykh (2000; ASP. Conf. Ser. 210, 215)**Excited modes**d Scuti b Cephei**Instability regions**Pamyatnykh (2000; ASP. Conf. Ser. 210, 215)**Breger (1995; ASP Conf. Ser. 76, 596)**Analysis techniques**FG Virginis**Breger et al. (2005; Astron. Astrophys. 435, 955)**FG Virginis frequencies**Breger et al. (2005)**FG Virginis frequencies**Breger et al. (2005)**FG Virginis amplitude distribution**Breger et al. (2005)**FG Virginis frequency interpretation**No rotation With rotation, nnlm = nnl0 + m W/2 p Templeton et al. (2001; ApJ 563, 999)**Altair: the brightest d Scuti star**Observations with the WIRE satellite Buzasi et al. (2005; ApJ 619, 1072)**Very slow pulsations**Poretti et al. (2002; Astron. Astrophys. 384, 513)**Very extended observations**Aerts et al. (2004; Astron. Astrophys. 415, 1079)**Instability region**Warner et al. (2003; ApJ 593, 1049)**Convective blocking**Guzik et al. (2002; ASP Conf. Ser. 259, 502)

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