Pulsations and magnetic activity in the IR Rafa Garrido & Pedro J. Amado Instituto de Astrofísica de Andalucía, CSIC. Granada

Radial dependence (n) Angular dependence (l,m) Acoustic oscillations

Standard solar model 1996 standard solar model inclusion of He settling & improved physics base of convection zone better physics for core needed

Standard solar model Differential rotation

Small and large separations Solar oscillations (VIRGO-SOHO)

Asteroseismic diagram: J. C. Christensen-Daslgaard, Rev. Mod. Phys., 74, 1073

 Scuti  Doradus Variability Zoo

Giants     Hya GSC   UMa  Boo

LAST RESULTS WITH HARPS B. Mosser (Corot week 6: May 2004, Orsay) A clear signature of the large separation :  89  Hz

HARPS PERFORMANCE 2 minutes integration time for V=6 on the ESO 3.6m: σ v =1 ms vsini= 0 kms -1 σ v =3 ms vsini=10 kms -1

Benefits from the IR Flux gain

Benefits from the IR magnetic sensitivity

Problems Theory Theory mode selection (amplitudes) mode selection (amplitudes) amplitude & phase changes amplitude & phase changes input physics in models input physics in models  convection & overshooting  diffusion & settling  rotation  magnetic field Observations Observations mode identification (spectroscopy & photometry) mode identification (spectroscopy & photometry) data analysis data analysis

Active stars: Science goals Dynamo geometry Dynamo geometry Solar-like or something different? Solar-like or something different? Polar spots and active belts Polar spots and active belts Spot structure Spot structure Resolved or not? Resolved or not? Differential rotation and meridional flows Differential rotation and meridional flows Lifetimes of individual spots and active regions Lifetimes of individual spots and active regions Stellar “butterfly diagrams” Stellar “butterfly diagrams” Different stellar types Different stellar types Pre-main sequence stars Pre-main sequence stars Young main-sequence stars with[out] radiative interiors Young main-sequence stars with[out] radiative interiors Subgiants and giants Subgiants and giants

Intensity AA v sin i-v sin iv(spot) v sin i-v sin iv(spot) Doppler Imaging

Data requirements Time-series of hi-res (R > 30000) spectra: Time-series of hi-res (R > 30000) spectra: Good supply of unblended intermediate-strength lines (!) Good supply of unblended intermediate-strength lines (!) Broad-band light-curves. Broad-band light-curves. TiO and other temperature diagnostics. TiO and other temperature diagnostics.

Least-Square Deconvolution Assume observed spectrum = mean profile convolved with depth-weighted line pattern: Assume observed spectrum = mean profile convolved with depth-weighted line pattern: De-convolve mean profile z k via least squares: De-convolve mean profile z k via least squares: S/N improves from ~100 to ~2500 per 3 km s –1 pixel with ~2500 lines. S/N improves from ~100 to ~2500 per 3 km s –1 pixel with ~2500 lines.  = Mean profile, z (UNKNOWN) Depth-weighted line pattern,  - KNOWN Rotationally broadened spectrum, r – KNOWN

DI Maps AB Dor

DI Maps VW Cep

ZDI Maps AB Dor

Benefits from the IR Spectral lines are less blended in the infrared. Hence, line profile variations are more clearly detected Spectral lines are less blended in the infrared. Hence, line profile variations are more clearly detected The Zeeman effect is enhanced for lines in the IR The Zeeman effect is enhanced for lines in the IR Radiation flux and pulsation amplitudes increase with increasing wavelength for cooler stars. Radiation flux and pulsation amplitudes increase with increasing wavelength for cooler stars. IR lines can probe different parts of the atmosphere. IR lines can probe different parts of the atmosphere.

Benefits from the IR Sun continuum contrast between photosphere and T spot = 4250 K: Sun continuum contrast between photosphere and T spot = 4250 K: 0.6 µ m ≈ 0.6 µ m 2.2 µ m ≈ 2.2 µ m Resolving the telluric absorption lines (intrinsically narrow ~5 km s −1 ) Pontoppidan & van Dishoeck, 2004, astroph Resolving the telluric absorption lines (intrinsically narrow ~5 km s −1 ) Pontoppidan & van Dishoeck, 2004, astroph Zeeman sensitivity: the Fe I line at 1.56 µ m splits by twice the FWHM in 1.5 kG fields (slowly rotating stars): 2-3 times more sensitive than optical lines (Giampapa PASP 109) Zeeman sensitivity: the Fe I line at 1.56 µ m splits by twice the FWHM in 1.5 kG fields (slowly rotating stars): 2-3 times more sensitive than optical lines (Giampapa PASP 109)