Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Seismology of Herbig stars with SIAMOIS Torsten Böhm, Marc-Antoine Dupret Claude Catala, Marie-Jo Goupil, Evelyne Alecian Observatoire de Paris-Meudon Observatoire Midi-Pyrénées

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Main observational properties of Herbig stars Seismic potential of Herbig stars: probing the internal structure of PMS stars HD : a very good target for SIAMOIS Discovery of 8 pulsating modes in HD Preliminary seismic study of HD Improvements expected with SIAMOIS Let’s talk about…

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Herbig Ae/Be stars - very young pre-main sequence objects - observational definition (Herbig, 1960): - spectral type earlier than F0 - presence of emission lines - embedded region - proximity of reflection nebula - intermediate masses ( solar masses) - signs of intense activity and strong stellar winds - In addition: jets, outflows, IR excess, X-ray sources, presence of CS disks, detection of magnetic fields, ….

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets HR diagram ZAMS

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Herbig Ae/Be stars - very young pre-main sequence objects - observational definition (Herbig, 1960): - spectral type earlier than F0 - presence of emission lines - embedded region - proximity of reflection nebula - intermediate masses ( solar masses) - signs of intense activity and strong stellar winds - In addition: jets, outflows, IR excess, X-ray sources, presence of CS disks, detection of magnetic fields, ….

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Discovery of pulsating Herbig Ae stars - the  Scuti instability strip crosses the location of HAeBes in the HR diagram - Until now, only some Herbig stars between A2 and F0 have been identified pulsating: - V588 Mon & - V599 Mon P < 3h (multip.) (Breger,1972) - HR5999P approx 6 hrs (Kurtz & Marang 1995) - HD P approx 40 minutes (Donati, 1997) … + some recent discoveries (approx 15 stars as of today)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Potential of Herbig stars for asteroseismology Probing the internal physics of stars in the early stages of evolution Location of the convective core Initial nuclear burning (CNO cycle)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Brunt Vaisala freq. Evolution tracks Probing the convective core in the early stages of evolution

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Small separation Comparison PreMS – PostMS frequencies

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Potential of Herbig stars for asteroseismology Probing the internal physics of stars in the early stages of evolution Location of the convective core Initial nuclear burning (CNO cycle) Internal rotation Transport of angular momentum

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets HD a PMS prototype star -Emission line star (Herbig Ae *) -Southern hemisphere (-78°) -mV approx 6.5 -Mass: 2.3 solar masses -Luminosity: 35 solar lum -Log Teff: Spectral type: A4IVe+sh -Vsini 12km/s -Highly active and variable (spectro) -Stellar wind 500km/s -Multiple system (+spectrosc. binary)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Previous work…

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets High resolution spectroscopic data base SAAO 04/19991 week SAAO 04/20001 weekGIRAFFE… SAAO 05/20002 weeks Mt Stromlo 04/001 week data reduction ESPRIT/ LSD (multiplex information) + cross-correllation of telluric lines 100m/s precision on vrad (per spectrum) spectra - total of 42 nights

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets SAAO at Sutherland

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Orbital analysis SAAO Avril Mt Stromlo Avril 2000 SAAO Mai 2000 SAAO Avril 1999  Amplitude!

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets 5 ascertained +3 probable frequencies Böhm et al. 2004, A&A 427, 907

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets 5 ascertained +3 probable frequencies

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets 1999

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets 1999: 3 probables frequencies…?

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets 2000 (total)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Observations and modelisation 1999 SAAO

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Rotational Modulation - 95 hrs Period Halpha

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets A: primary B: secondary ZAMS Preliminary seismic study Van den Ancker et al. T eff =8500 K Grady et al. T eff =7500 K Bohm et al. (in prep.) T eff =8250 K

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Preliminary seismic study M=2.2 M 0 M=2.7 M 0

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Observed frequencies Preliminary seismic study

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Preliminary seismic study M=2.2 M 0 M=2.7 M 0

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Preliminary seismic study

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Preliminary seismic study M=2.2 M 0 M=2.7 M 0

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Rot. Splitting ? (~ 3  Hz)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Second order effect More splittings could be detected by SIAMOIS

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Small separation (  Hz)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Small separation (  Hz) M=2.3 M 0 Y=0.27 [Fe/H]=0 M=2.23 M 0 Y=0.29 [Fe/H]=0 M=2.41 M 0 Y=0.27 [Fe/H]=0.2 ( Dif. ~ 0.1  Hz) Possible with SIAMOIS

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Preliminary seismic study Excitation mechanism Unknown up to now Stochastic excitation  Scuti type  -driving No convection zoneToo high frequencies RoAp type driving ?Helium settling, winds, magnetic f. Enhanced  -driving in the H partial ionization zone In collaboration with S. Theado, Liège

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Improvements with SIAMOIS Many new modes 3 – 4 months Duty cycle: % Noise level : m/s (120h) Frequency precision : 0.1  Hz Rotational splittings Internal rotation Small difference Constraining the Internal physics Excitation mechanisms

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Major results on HD Orbital study: mass ratio primary/secondary / Palla & Staler’s evolutionary tracks: secondary K3, 0.5 Lsol -Multi-periodic pulsations (5 frequencies ascertained + 3 potential) -frequences characteristical of  Scuti stars -Strong variation of amplitudes between seasons -Coherence of the modes on at least 2 month (resolved periodogram) -Rotational modulation of 95hrs (to be confirmed) -Separation between frequencies indicates presence of non-radial modes; first asterosismological models

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets Next steps -Modeling -Internal structure of HD ? -model of pulsating HD > modes -> frequencies -need for precise Teff, log g, metallicities -Activity-Confirm rotational modulation -Search for correlation of HeI5876A, H alpha with orbital period -Search for accretion tracers CS environment - star -study of the wind -study of the forbidden lines, tracers of CS environment -Pulsation-systematic search for patterns (dynamical spectra) -2D Periodicity analysis -moment method -Selectif LSD for specific elements (  phase, A?)

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets First asterosismological models (1) Teff = 8250 K « low » radial modes large separation not matching

Kick-off meeting SIAMOIS Paris, mai 2006 PMS targets First Asterosismological models (2) Teff = 7650 K (?) « high » radial modes large separation « matching » Model by Marc Antoine Dupret, OBSPM, Paris, France