P-type pulsators on the main sequence of HR Diagram
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Transcript of P-type pulsators on the main sequence of HR Diagram
P-type pulsators on the main sequence of HR Diagram
Gyöngyi KerekesCOROT-day Budapest March, 2007
HRD
δ Scuti
β Cephei
SPB
γ Doradus
Comparison
Type Period Amplitude (in magnitude)
Spectral
type
β Cephei 3-8 hours 0.01-0.8 B2-B5
δ Scuti 1-3 hours 0.03-0.9 A0-F5
δ Scuti HD 170782
• Vmag = 7.81
• Spectral type: A2• Outside of the instability strip, blue
edge• Reopens the problem of variability
Whitening
1
2
3 4 5 6
123456
Fitting
Frequencies of HD 170782
Frequency
(cycle/day)
Amplitude(magnitude)
Phase Noise (S/N)
2.9 0.0081 0.83 18.79
4.1 0.0064 0.45 14.91
25.5 0.0031 0.63 8.84
13.2 0.0026 0.02 5.9
7.8 0.0020 0.33 4.2
Frequency
(cycle/day)
Amplitude(magnitude)
Phase Noise (S/N)
2.9 0.0081 0.83 18.79
4.1 0.0064 0.45 14.91
25.5 0.0031 0.63 8.84
13.2 0.0026 0.02 5.9
7.8 0.0020 0.33 4.2
β Cephei stars
• Known since 1902• 10-20 solar masses• Main pulsation modes radial • But non-radial pulsations also detected• Large fraction is multiperiodic• Frequency spectrum is not too dense
modelling becomes possible• Very interesting from astroseismologic
point of view
β Cephei HD 180642
• Main target of the first COROT long run
• Vmag = 8.3
• Spectral type: B 1.5
Whitening
1
2
3
4 5 6 7
1234567
Fitting
Frequencies
Frequency
(cycle/day)
Amplitude(magnitude
)Phase
Noise (S/N)
5.49 0.037 0.83 36.015
0.43 0.010 0.48 10.659
9.97 0.009 0.12 8.804
0.35 0.005 0.98 5.351
8.81 0.005 0.54 5.524
16.88 0.004 0.91 4.59
Frequency
(cycle/day)
Amplitude(magnitude
)Phase
Noise (S/N)
5.49 0.037 0.83 36.015
0.43 0.010 0.48 10.659
9.97 0.009 0.12 8.804
0.35 0.005 0.98 5.351
8.81 0.005 0.54 5.524
16.88 0.004 0.91 4.59
Conclusions
• Main obtained frequencies:
• Trends in light curves↓
Further cleanings are required
• HD 170782 belongs to small amplitude δ Scutis → maybe more modes are excited → COROT’s task to investigate if there are more modes
δ Scuti HD
170782
25.5
13.2
7.8
β Cephei
HD 180642
5.5
9.97
8.81
16.88
Thank you for your attention!