TY - GEN
T1 - Exploring the magnetic topologies of cool stars
AU - Morin, J.
AU - Donati, J. F.
AU - Petit, P.
AU - Albert, L.
AU - Auriére, M.
AU - Cabanac, R.
AU - Catala, C.
AU - Delfosse, X.
AU - Dintrans, B.
AU - Fares, R.
AU - Forveille, T.
AU - Gastine, T.
AU - Jardine, M.
AU - Konstantinova-Antova, R.
AU - Lanoux, J.
AU - Lignires, F.
AU - Morgenthaler, A.
AU - Paletou, F.
AU - Ramirez Velez, J. C.
AU - Solanki, S. K.
AU - Thado, S.
AU - Van Grootel, V.
N1 - Funding Information:
The presentation of this paper in the IAU Symposium 273 was possible due to partial support from the National Science Foundation grant numbers ATM 0548260, AST 0968672 and NASA - Living With a Star grant number 09-LWSTRT09-0039.
PY - 2010/8
Y1 - 2010/8
N2 - Magnetic fields of cool stars can be directly investigated through the study of the Zeeman effect on photospheric spectral lines using several approaches. With spectroscopic measurement in unpolarised light, the total magnetic flux averaged over the stellar disc can be derived but very little information on the field geometry is available. Spectropolarimetry provides a complementary information on the large-scale magnetic topology. With Zeeman-Doppler Imaging (ZDI), this information can be retrieved to produce a map of the vector magnetic field at the surface of the star, and in particular to assess the relative importance of the poloidal and toroidal components as well as the degree of axisymmetry of the field distribution. The development of high-performance spectropolarimeters associated with multi-lines techniques and ZDI allows us to explore magnetic topologies throughout the Hertzsprung-Russel diagram, on stars spanning a wide range of mass, age and rotation period. These observations bring novel constraints on magnetic field generation by dynamo effect in cool stars. In particular, the study of solar twins brings new insight on the impact of rotation on the solar dynamo, whereas the detection of strong and stable dipolar magnetic fields on fully convective stars questions the precise role of the tachocline in this process.
AB - Magnetic fields of cool stars can be directly investigated through the study of the Zeeman effect on photospheric spectral lines using several approaches. With spectroscopic measurement in unpolarised light, the total magnetic flux averaged over the stellar disc can be derived but very little information on the field geometry is available. Spectropolarimetry provides a complementary information on the large-scale magnetic topology. With Zeeman-Doppler Imaging (ZDI), this information can be retrieved to produce a map of the vector magnetic field at the surface of the star, and in particular to assess the relative importance of the poloidal and toroidal components as well as the degree of axisymmetry of the field distribution. The development of high-performance spectropolarimeters associated with multi-lines techniques and ZDI allows us to explore magnetic topologies throughout the Hertzsprung-Russel diagram, on stars spanning a wide range of mass, age and rotation period. These observations bring novel constraints on magnetic field generation by dynamo effect in cool stars. In particular, the study of solar twins brings new insight on the impact of rotation on the solar dynamo, whereas the detection of strong and stable dipolar magnetic fields on fully convective stars questions the precise role of the tachocline in this process.
KW - Brown dwarfs
KW - Stars: activity
KW - Stars: low-mass
KW - Stars: magnetic fields
KW - Stars: rotation
KW - Techniques: polarimetric
KW - Techniques: spectroscopic
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U2 - 10.1017/S1743921311015213
DO - 10.1017/S1743921311015213
M3 - Conference contribution
AN - SCOPUS:84882973619
SN - 9780521760621
T3 - Proceedings of the International Astronomical Union
SP - 181
EP - 187
BT - The Physics of Sun and Star Spots
A2 - Choudhary, Debi Prasad
A2 - Strassmeier, Klaus
ER -