Sylvie VauclairLaboratoire d’Astrophysique de Toulouse-Tarbes, CNRS,Université de Toulouse, Institut universitaire de France

SONG Beijing meeting, March-April 2010

Precise modelling and asteroseismologyof exoplanet-host stars.

Why bothering about asteroseismologywhen studying exoplanets?

1) Same instruments, same observations, different time scales

2) Some people’s noise is other people’s signal

3) Obtain precise values of the parameters of exoplanets hosts stars

4) Links between asteroseismology and planets discoveries

SOPHIE OHP, T193August 2007

Richard, Michaud, Richer, ApJ 558, 391, 2001 (precise computations, OPAL)

More recently:Théado, Vauclair, Alecian, Leblanc, ApJ 704, 1262, 2009 (SVP approximation, OP)

1.5 Msun

Double-diffusive convection (thermohaline) : c.f. S. Vauclair , ApJ 605, 874, 2004

Théado, Vauclair, Alecian, Leblanc, ApJ 704, 1262, 2009

Fe/Fe0 1.7 Msun

log 1.7 Msun

1.7 Msun

many applications: SPB/Ceph, sdB, Dor, etc.

119 planet-host stars (dashed) ; 94 comparison stars (solid)

Exoplanets host stars

22 planet-host stars in binary systems (solid) ; dashed : single planet-host stars

Santos et al. 2005

Santos et al 2003

But!!!

heavy elements and… problem of Y

Pepe et al. 2007, A&A, 462, 769

Mu Arae

Bouchy, Bazot, Santos, Vauclair, Sosnowska 2005

43 detected modes , l = 0 to 3

AraeHD 160691

Soriano & Vauclair , A&A 2010

1.06 Msun

1.20 Msun

1.15 Msun

1.10 Msun

L/Ls

un

Soriano et al 2010 Arae

[Fe/H] = 0.29 [Fe/H] = 0.32 1.06 1.06

1.06 1.06

1.12 1.12

1.18

1.20

1.14

1.20

1.24

1.16

Mu Arae

model OM1, Yg, 1.10 Msun, 6.3 Gyr, [Fe/H]=0.32

Model with overshooting, ov = 0.20

For crossing points and negative small separations, see :Soriano, M., Vauclair, S. 2008, A&A, 488, 975

turning point of the l=2 waves:

where Sl(rt) is the Lamb frequency:

iota Horologii : seismic analysis…

… and best models

( For each metallicity, Teff of best model decreases for decreasing Y )

Vauclair et al., submitted to A&A

Best seismic models Hyades (Lebreton et al. 2001)

(Chereul et al 1999 ; Chereul and Grenon 2000) Hor belongs to the Hyades stream

Conclusions:waiting for SONGmuch work for future students!