تقرير
Linking chromospheric activity and magnetic field properties for late-type dwarf stars
| العنوان: | Linking chromospheric activity and magnetic field properties for late-type dwarf stars |
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| المؤلفون: | Brown, E. L., Jeffers, S. V., Marsden, S. C., Morin, J., Saikia, S. Boro, Petit, P., Jardine, M. M., See, V., Vidotto, A. A., Mengel, M. W., Dahlkemper, M. N., Collaboration, the BCool |
| سنة النشر: | 2022 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | Spectropolarimetric data allow for simultaneous monitoring of stellar chromospheric $\log{R^{\prime}_{\rm{HK}}}$ 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 $\log{R^{\prime}_{\rm{HK}}}$ 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 $\log{R^{\prime}_{\rm{HK}}}$ and mean $\log|B_l|$, but for G stars the relationship may undergo a change between $\log{R'_{\rm{HK}}}\sim-4.4$ and $-4.8$. The mean $\log{R^{\prime}_{\rm{HK}}}$ shows a similar change with respect to the $\log{R^{\prime}_{\rm{HK}}}$ 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 $-4.75\leq\log{R'_{\rm HK}}\leq-4.5$. 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 $\log{R'_{\rm HK}}$ 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. Comment: 20 pages, 15 figures, 3 tables |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1093/mnras/stac1291 |
| الوصول الحر: | http://arxiv.org/abs/2205.03108Test |
| رقم الانضمام: | edsarx.2205.03108 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1093/mnras/stac1291 |
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