Transcript ppt

Constraints on the radial
differential rotation of six
Sun-like stars
Martin Bo Nielsen
Laurent Gizon, Hannah Schunker
and Jesper Schou
Institute for Astrophysics Göttingen
Max Planck Institute for Solar System Research
Dec. 5th 2014
Plato 2.0 Science Conference, Taormina, Italy
Internal rotation, why do we care?
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Stellar dynamos
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Gyrochronology
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Differential rotation
Shear layer regenerates
magnetic field
Stellar wind
Internal angular momentum?
Schou et al. (1998)
Stellar models
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Structure and evolution
Martin Nielsen, Plato 2.0
Asteroseismology
CoRoT – HD52265
Gizon et al. 2013
Kepler – HAT-P-7
Lund et al. 2014
Martin Nielsen, Plato 2.0
Six Sun-like Kepler Stars
Star
Teff [K]*
logg [cm/s/s]*
Spot rotation
period [days]
KIC004914923
5808±92
4.28±0.21
24
KIC005184732
5669±97
4.07±0.21
21
KIC006106415
6050±70
4.40±0.08
-
KIC006116048
5991±124
4.09±0.21
18
KIC006933899
5837±97
4.21±0.22
32
KIC010963065
6097±130
4.00±0.21
12
*Molenda-Żakowicz et al. 2013
Martin Nielsen, Plato 2.0
Peakbagging
l=0
l=1
m = 0,±1
l=2
m = 0,±1,±2
Martin Nielsen, Plato 2.0
Splitting and inclination
Nielsen et al. (2014)
Martin Nielsen, Plato 2.0
Spot rotation vs. asteroseismology
Davies et al. in prep.
Martin Nielsen, Plato 2.0
Summary
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Constrained radial differential rotation for six Sun-like
stars.
Appears very consistent with comparison to solar data.
Rotation periods measured by asteroseismology and
starspots are consistent.
Possible improvements:
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Fitting ensembles of PLATO stars
Accurate treatment of mode widths
Fit using specific profile (e.g. step function)
Thank you
Martin Nielsen, Plato 2.0