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| Paper: |
Observational Evidence for a Non Solar-Type Dynamo Operating in
Late-Type Stars |
| Volume: |
449, Astronomical Polarimetry 2008: Science from Small to Large Telescopes |
| Page: |
285 |
| Authors: |
Jeffers, S. V.; Donati, J. |
| Abstract: |
We present high-resolution images of the young rapidly rotating G0
dwarf HD 171488 using both Stokes I and Stokes V data taken over four
epochs. Using the good phase coverage of our data we measure
differential rotation for each epoch. The results show the highest
measurements of differential rotation ever measured using
Zeeman-Doppler imaging techniques. We also find that the differential
rotation measurement obtained from Stokes V data is approximately the
same as that derived from the Stokes I data and that they show no
temporal evolution. Other measurements of differential rotation using
both brightness and magnetic data have been made for the K1 V AB Dor
where there is a large variation between the two data
sets. For AB Dor this indicates that
magnetic regions are not anchored at the same depth in the convective
zone, and therefore do not experience the same shear. The marginal
difference in the differential rotation measurements for Stokes I and
V data and the absense of any temporal evolution for HD 171488 further
supports the existence of a non solar-type dynamo, as HD 171488 has a
much thinner convective zone than AB Dor. |
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