Linking chromospheric activity and magnetic field properties for late-type dwarf stars

Autor(en)

, E. L. Brown, S. V. Jeffers, S. C. Marsden, J. Morin, S. Boro Saikia, P. Petit, M. M. Jardine, V. See, A. A. Vidotto, M. W. Mengel, M. N. Dahlkemper

Abstrakt

Spectropolarimetric data allow for simultaneous monitoring of stellar chromospheric logR'_HK activity and the surface-averaged longitudinal magnetic field, B_l, giving the opportunity to probe the relationship between large-scale stellar magnetic fields and chromospheric manifestations of magnetism. We present logR'_HK and/or B_l measurements for 954 mid-F to mid-M stars derived from spectropolarimetric observations contained within the PolarBase database. Our magnetically active sample complements previous stellar activity surveys that focus on inactive planet-search targets. We find a positive correlation between mean logR'_HK and mean log |B_l|, but for G stars the relationship may undergo a change between logR'_{HK ~} -4.4 and -4.8. The mean logR'_HK shows a similar change with respect to the logR'_HK variability amplitude for intermediately active G stars. We also combine our results with archival chromospheric activity data and published observations of large-scale magnetic field geometries derived using Zeeman-Doppler Imaging. The chromospheric activity data indicate a slight under-density of late-F to early-K stars with -4.75 ≤ logR'_HK ≤ -4.5. This is not as prominent as the original Vaughan-Preston gap, and we do not detect similar under-populated regions in the distributions of the mean |B_l|, or the B_l and logR'_HK variability amplitudes. Chromospheric activity, activity variability, and toroidal field strength decrease on the main sequence as rotation slows. For G stars, the disappearance of dominant toroidal fields occurs at a similar chromospheric activity level as the change in the relationships between chromospheric activity, activity variability, and mean field strength.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Southern Queensland, Max-Planck-Institut für Sonnensystemforschung, Université de Montpellier, Université de Toulouse, University of St. Andrews, European Space Research & Technology Centre (ESA/ESTEC), University of Exeter, University of Dublin, Leiden University, Georg-August-Universität Göttingen, European Organization for Nuclear Research (CERN)

Journal

Monthly Notices of the Royal Astronomical Society

Band

514

Seiten

4300-4319

Anzahl der Seiten

20

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stac1291

Publikationsdatum

08-2022

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/19f906f6-3b07-4362-832f-8ef06ba2655d