Zeeman-Doppler imaging of five young solar-type stars. (arXiv:2110.06729v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Willamo_T/0/1/0/all/0/1">T. Willamo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lehtinen_J/0/1/0/all/0/1">J. J. Lehtinen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hackman_T/0/1/0/all/0/1">T. Hackman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kapyla_M/0/1/0/all/0/1">M. J. Käpylä</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kochukhov_O/0/1/0/all/0/1">O. Kochukhov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jeffers_S/0/1/0/all/0/1">S. V. Jeffers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Korhonen_H/0/1/0/all/0/1">H. Korhonen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marsden_S/0/1/0/all/0/1">S. C. Marsden</a>
The magnetic activity of the Sun changes with the solar cycle. Similar cycles
are found in other stars as well, but their details are not known to a similar
degree. Characterising stellar magnetic cycles is important for the
understanding of the stellar and solar dynamos that are driving the magnetic
activity. We present spectropolarimetric observations of five young, solar-type
stars, and compare them to previous observations, with the aim to identify and
characterise stellar equivalents of the solar cycle. We use Zeeman-Doppler
imaging (ZDI) to map the surface magnetic field and brightness of our targets.
The magnetic field is decomposed into spherical harmonic expansions, from which
we report the strengths of the axisymmetric vs. non-axisymmetric, and poloidal
vs. toroidal components, and compare them to the Rossby numbers of the stars.
We present five new ZDI-maps of young, solar-type stars from Dec 2017. Of
special interest is the case of V1358 Ori, that has gone through a polarity
reversal between our observations and earlier ones. A less evident polarity
reversal might also have occurred in HD 35296. There is a preference for more
axisymmetric field, and possibly more toroidal field, for the more active stars
with lower Rossby number, but a larger sample should be studied to draw any
strong conclusions from this. For most of the individual stars, the amounts of
toroidal and poloidal field have stayed on similar levels as in earlier
observations. We find evidence for a magnetic polarity reversal having occurred
in V1358 Ori. c{hi}1 Ori could be an interesting target for future
observations, with a possible short magnetic cycle of a few years. The
correlation between the brightness maps and the magnetic field is mostly poor,
which could indicate the presence of small-scale magnetic features of different
polarities, that cancel each other out, and are not resolved in our maps.
The magnetic activity of the Sun changes with the solar cycle. Similar cycles
are found in other stars as well, but their details are not known to a similar
degree. Characterising stellar magnetic cycles is important for the
understanding of the stellar and solar dynamos that are driving the magnetic
activity. We present spectropolarimetric observations of five young, solar-type
stars, and compare them to previous observations, with the aim to identify and
characterise stellar equivalents of the solar cycle. We use Zeeman-Doppler
imaging (ZDI) to map the surface magnetic field and brightness of our targets.
The magnetic field is decomposed into spherical harmonic expansions, from which
we report the strengths of the axisymmetric vs. non-axisymmetric, and poloidal
vs. toroidal components, and compare them to the Rossby numbers of the stars.
We present five new ZDI-maps of young, solar-type stars from Dec 2017. Of
special interest is the case of V1358 Ori, that has gone through a polarity
reversal between our observations and earlier ones. A less evident polarity
reversal might also have occurred in HD 35296. There is a preference for more
axisymmetric field, and possibly more toroidal field, for the more active stars
with lower Rossby number, but a larger sample should be studied to draw any
strong conclusions from this. For most of the individual stars, the amounts of
toroidal and poloidal field have stayed on similar levels as in earlier
observations. We find evidence for a magnetic polarity reversal having occurred
in V1358 Ori. c{hi}1 Ori could be an interesting target for future
observations, with a possible short magnetic cycle of a few years. The
correlation between the brightness maps and the magnetic field is mostly poor,
which could indicate the presence of small-scale magnetic features of different
polarities, that cancel each other out, and are not resolved in our maps.
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