Toulouse May 2005 Corot-Week 8 δ Scuti and γ Dor stars in COROT Rafael Garrido IAA, Granada...

Toulouse May 2005Toulouse May 2005 Corot-Week 8 Corot-Week 8

δδ Scuti and Scuti and γγ Dor stars in Dor stars in

COROTCOROT

Rafael GarridoRafael Garrido

IAA, Granada (Spain)IAA, Granada (Spain)


Current ground based observationsCurrent ground based observations

δδ Scuti:Scuti: 0.3 – 3 hours (p- and mixed modes) 0.3 – 3 hours (p- and mixed modes)

γγ Doradus:Doradus: 0.4 – several days (g-modes) 0.4 – several days (g-modes)

both regimes? (Dupret et al. 2004 A&A 414, L17)both regimes? (Dupret et al. 2004 A&A 414, L17)

and and Solar likeSolar like oscillations? (Samadi et al. 2002 A&A 395, 563) oscillations? (Samadi et al. 2002 A&A 395, 563)

Mode identification:Mode identification:

Frequency differences: Sismo & ExoFrequency differences: Sismo & Exo

Frequency combinations: Sismo & ExoFrequency combinations: Sismo & Exo

Colour information: ExoColour information: Exo

Frequency Ratio Method (Frequency Ratio Method (γγ Dor)Dor) : Sismo & Exo : Sismo & Exo


FG VirCurrent ground based observationsCurrent ground based observations

Breger et al. 2004 A&A 419, 695


Breger et al. 2004 A&A 419, 695




Breger et al. 2004 A&A 419, 695

FG Vir


Breger et al. 2004 A&A 419, 695




Breger et al. 2004 A&A 419, 695

FG Vir



DFT (Daily Aliasing)DFT (Daily Aliasing)

Frequencies estimations:Frequencies estimations:

simultaneous n-fitting at step nsimultaneous n-fitting at step n

Frequency errors:Frequency errors:

Rayleigh resolution (1/T)Rayleigh resolution (1/T)

oror

non-linear fitting non-linear fitting

Amplitude and phase errors:Amplitude and phase errors:

least square fitting at fixed frequenciesleast square fitting at fixed frequencies


Schwanzerberg-Czerny 1991 MNRAS, 253, 198:

Uncorrelated observationsUncorrelated observations

σσ(F) = √6/(F) = √6/ππ * (N/S) * (1/√Nt) * (1/T) * (N/S) * (1/√Nt) * (1/T)

S/N Signal to Noise ratioS/N Signal to Noise ratio Nt Total number of observationsNt Total number of observations T Time baseT Time base

Correlated observations Correlated observations

σσ(F)= √D * (F)= √D * σσ(F) (F) D Correlation length (“post mortem”)D Correlation length (“post mortem”)


Present ground based observationsPresent ground based observations

Amplitude and phases errors:Amplitude and phases errors:

Least squares at fixed frequenciesLeast squares at fixed frequencies

Best errors values for ground based : Best errors values for ground based :

0.05 mmags and 0.5 degrees.0.05 mmags and 0.5 degrees.

Main results for Main results for δδ Scuti Scuti::

Amplitude and phase variationsAmplitude and phase variations


Breger, M. 2000, MNRAS 313, 129Rodriguez et al. 1998, A&A 338, 905 28 And

Amplitude variationsAmplitude variations

4 CVn


Breger, M. 2000, MNRAS 313, 129Breger, M. 2000, MNRAS 313, 129

Garrido & Rodriguez 1996 MNRAS 281, 696Garrido & Rodriguez 1996 MNRAS 281, 696

4 CVn


Wavelets (Equally spaced Wavelets (Equally spaced data):data):

Mexican hatMexican hat MorletMorlet


Wavelets (Equally spaced Wavelets (Equally spaced data):data):


Bispectra (Equally spaced data)Bispectra (Equally spaced data)

non zero only when quadratic coupling exists !


SOHO: bispectrum modulus.SOHO: bispectrum modulus.

Toulouse May 2005Toulouse May 2005 Corot-Week 8 Corot-Week 8 z

Suárez et al. 2005, A&A SubmittedSuárez et al. 2005, A&A Submitted


Breger et al. 1999 A&A 341, 151Breger et al. 1999 A&A 341, 151

Frequency differencesFrequency differences FG Vir


p7

p1

1.4 M0

1.6 M0

1.8 M0

2 M0

2.2 M0

= 0.5 - = 0

δδ Scuti Stars Scuti Stars Red borderRed border

Grigahcene et al. 2005 A&A 434, 1055

Dupret et al. 2004 A&A 414, L17

Dupret et al. 2005 A&A 435, 927


p7

p1

1.4 M0

2 M0

1.8 M0

1.6 M0

2.2 M0

= 1 - = 0




Dupret et al. 2005 A&A 435, 927


p1p7

p1

1.4 M0

1.8 M0

2 M0

2.2 M0

1.6 M0

= 1.5 - = 0




Dupret et al. 2005 A&A 435, 927


p6

fB

g7

fR

1.4 M0

2 M0

2.2 M0

1.8 M0

1.6 M0

= 1.5 - = 2




Dupret et al. 2005 A&A 435, 927


γγ Doradus stars Doradus starsg- and p-unstable modesg- and p-unstable modes

1.5 M0 - l = 1 - a = 1.5



Dupret et al. 2005 A&A 435, 927


γγ Doradus stars Doradus stars Instability stripInstability strip



Dupret et al. 2005 A&A 435, 927


Moya et al. 2005 A&A, 432, 189Suarez et al. 2005 A&A submitted

γγ Doradus stars Doradus stars Frequency ratio methodFrequency ratio method

Poretti et al. 2003 A&A 406, 203Poretti et al. 2005 A. J. 129, 2461


CONCLUSIONSCONCLUSIONS

COROT data:COROT data:

• Continuous data (no alias, techniques requiring Continuous data (no alias, techniques requiring

equally spaced data, high Nyquist frequency for equally spaced data, high Nyquist frequency for

sismo data)sismo data)

• Exploration of the high frequency region (Solar Exploration of the high frequency region (Solar

like?)like?)

• Discovery of unique objects (Discovery of unique objects (δδ Scuti + Scuti + γγ Dor + Dor +

solar like?)solar like?)

• Amplitude, phase (and frequency?) changesAmplitude, phase (and frequency?) changes

• Mode identification (frequency differences, Mode identification (frequency differences,

linear combinations, colours, FRM)linear combinations, colours, FRM)

Toulouse May 2005 Corot-Week 8 δ Scuti and γ Dor stars in COROT Rafael Garrido IAA, Granada...

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