Diapositive 1

Prospects for asteroseismology of solar-like starsT. Appourchaux

Institut dAstrophysique Spatiale, Orsay

ContentsWhat is a solar-like star?A shopping list for physicsThe store: PLATO 2.0Summary2HELAS VI: Helioseismology and applicationsWhat is meant by a solar-like star?3HELAS VI: Helioseismology and applicationsHoudek et al (2000)Huber (2014)

Huber et al (2011)In blue classical pulsators, in red stochastically excited3Shopping list for physicsInternal rotation (Subgiant stars, MS star)Helium ionization and convection zonesExcitation and damping (mode physics)Stellar cycle and activityAtmosphere: surface effect, asymmetriesStellar Radius, Mass and AgeClusters and Binary stars4HELAS VI: Helioseismology and applicationsRotation in solar-like stars5HELAS VI: Helioseismology and applications

Nielsen et al (2014)

Davies et al (2014)Seismically derived rotation provides light on differential rotation and gyrochronology (a few stars)

Rotation in evolved stars6HELAS VI: Helioseismology and applications

Deheuvels et al (2014)Subgiant stars having mixed modes provides the stellar rotation as a function of depth(6 stars)g-mode likep-mode likeSecond differences: in depths...7HELAS VI: Helioseismology and applications

Mazumdar et al (2014)

BCZHeIISignatures and depths of the base of the convection and second Helium ionization zones(20 stars) ...leading to Helium abundance8HELAS VI: Helioseismology and applications

Verma et al (2014)Amplitude of the signature of the second Helium ionization zone as a marker of helium abundance(1 star) Mode physics: linewidth et al9HELAS VI: Helioseismology and applications

Appourchaux et al (2014)Different inferred background affects mode-physic parameters (and vice versa)Stellar linewidths10HELAS VI: Helioseismology and applications

Appourchaux et al (2014)Linewidth depression at nmax decreases with effective temperature(23 stars)Stellar activity11HELAS VI: Helioseismology and applications

Garcia et al (2010)Garcia et al (2013)Studies of stellar activity impact on seismic parameters to be done on more stars than just 2!SunHD49933Departure from Lorentzian mode profile (asymmetry)12HELAS VI: Helioseismology and applications

Toutain and Kosovichev (2005)Mode asymmetry yet to be detected in other stars than the Sun (impact on stellar modelling)Surface effects13HELAS VI: Helioseismology and applications

Ball and Gizon (2014)Understanding and proper modelling of surface effect key for stellar modelling(8 stars)Stellar mass and radius14HELAS VI: Helioseismology and applications

Huber et al (2012)White et al (2014)

Lebreton and Goupil (2014) Calibration of scaling laws using interferometry From scaling laws to stellar modellingStellar age15HELAS VI: Helioseismology and applications

Lebreton and Goupil (2014)Metcalfe et al (2012)

Age calibration possible on binary stars(3 binary stars)Age determination on single stars(>50 stars)No seismic proxy for stellar age (yet), model comparison required using frequencies and /or ratioBinary stars16HELAS VI: Helioseismology and applications

Chaplin et al (2014)Seismic binary detection 0.5% for MS and subgiant stars to 1% for Red giantsA "typical" seismic binary (Kepler)Appourchaux et al (2012)"Speckle-Interferometry" binaryClusters17HELAS VI: Helioseismology and applications

Seismic scaling relation provides ways of identifying cluster membersStello et al (2011)

Appourchaux et al (1993)Improved stellar age precision and other stellar parameters with cluster by a factor 3(No cluster MS stars but...cluster RG stars)

Credits: G. Perez Diaz, IAC (MultiMedia Service)PLATO 2.0PLATO 2.0 in short19HELAS VI: Helioseismology and applications- Selected by ESA in February 2014 - 32 Normal 12cm cameras, cadence 25 s, white light 2 Fast 12cm cameras, cadence 2.5 s, 2 colours Dynamic range: 4 mV 16 L2 orbit Nominal mission duration: 6 years launched in 2024 2 long pointings of 2-3 years + step-and-stare phase (2-5 months per pointing)

PLATO 2.0 targets20HELAS VI: Helioseismology and applications4300 deg2 (long stare fields)20,000 deg2 (plus step and stare fields)Noise Level (ppm/hr)Number of cool starsmVNumber of cool stars34

(Asteroseismology)

22,0009.8-11.385,00080(Earth radius detection) 267,00011.6-12.91,000,000

For the Baseline missionSummaryStellar physics will face a revolution with PLATO 2.0Stellar physics will improve in the following fields:Stellar evolutionInternal structure and rotation (g modes?)Convection zone, HeII zoneStellar activitySeismic inversion and diagnostics (left out here...)Stellar physics will be calibrated with:Binary stars and clusters21HELAS VI: Helioseismology and applicationsPLATO 2.0 observing strategy22HELAS VI: Helioseismology and applicationsBaseline observing strategy:6 years nominal science operation2 long pointings of 2-3 years + step-and-stare phase (2-5 months per pointing)