Constraints on the radial Constraints on the radial differential rotation of six differential rotation of six

Sun-like starsSun-like stars

Martin Bo NielsenMartin Bo NielsenLaurent Gizon, Hannah Schunker Laurent Gizon, Hannah Schunker

and Jesper Schouand Jesper SchouInstitute for Astrophysics GöttingenInstitute for Astrophysics Göttingen

Max Planck Institute for Solar System ResearchMax Planck Institute for Solar System Research

Dec. 5Dec. 5thth 2014 2014Plato 2.0 Science Conference, Taormina, Plato 2.0 Science Conference, Taormina,

ItalyItaly

Internal rotation, why do we Internal rotation, why do we care?care? Stellar dynamosStellar dynamos

Differential rotationDifferential rotation Shear layer regenerates Shear layer regenerates

magnetic fieldmagnetic field

GyrochronologyGyrochronology Stellar windStellar wind Internal angular Internal angular

momentum?momentum?

Stellar modelsStellar models Structure and evolutionStructure and evolution

Schou et al. (1998)

Martin Nielsen, Plato 2.0

Martin Nielsen, Plato 2.0

AsteroseismologyAsteroseismology

CoRoT – HD52265 Kepler – HAT-P-7

Gizon et al. 2013 Lund et al. 2014

Martin Nielsen, Plato 2.0

StarStar Teff [K]*Teff [K]* logg [cm/s/s]*logg [cm/s/s]* Spot rotation Spot rotation period [days]period [days]

KIC004914923 5808±92 4.28±0.21 2424

KIC005184732 5669±97 4.07±0.21 2121

KIC006106415 6050±70 4.40±0.08 --

KIC006116048 5991±124 4.09±0.21 1818

KIC006933899 5837±97 4.21±0.22 3232

KIC010963065 6097±130 4.00±0.21 1212

*Molenda-Żakowicz et al. 2013

Six Sun-like Kepler StarsSix Sun-like Kepler Stars

Martin Nielsen, Plato 2.0

PeakbaggingPeakbagging

l=2m = 0,±1,±2

l=1m = 0,±1

l=0

Martin Nielsen, Plato 2.0

Splitting and inclinationSplitting and inclination

Nielsen et al. (2014)

Martin Nielsen, Plato 2.0

Spot rotation vs. asteroseismologySpot rotation vs. asteroseismology

Davies et al. in prep.

Martin Nielsen, Plato 2.0

SummarySummary Constrained radial differential rotation for six Sun-Constrained radial differential rotation for six Sun-

like stars.like stars.

Appears very consistent with comparison to solar Appears very consistent with comparison to solar data.data.

Rotation periods measured by asteroseismology Rotation periods measured by asteroseismology and starspots are consistent.and starspots are consistent.

Possible improvements: Possible improvements: Fitting ensembles of PLATO starsFitting ensembles of PLATO stars Accurate treatment of mode widthsAccurate treatment of mode widths Fit using specific profile (e.g. step function) Fit using specific profile (e.g. step function)

Thank you