English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Pre-main sequence stars are variable sources. In diskless stars thisvariability is mainly due to the rotational modulation of dark photosphericspots and active regions, as in main sequence stars even if associated with astronger magnetic activity. Aims. We aim at analyzing the simultaneous opticaland X-ray variability in these stars to unveil how the activity in thephotosphere is connected with that in the corona, to identify the dominantsurface magnetic activity, and to correlate our results with stellarproperties, such as rotation and mass. Methods. We analyzed the simultaneousoptical and X-ray variability in stars without inner disks (e.g., class IIIobjects and stars with transition disks) in NGC 2264 from observations obtainedwith Chandra/ACIS-I and CoRoT as part of the Coordinated Synoptic Investigationof NGC 2264. We searched for those stars whose optical and X-ray variability iscorrelated, anti-correlated, or not correlated by sampling their optical andX-ray light curves in suitable time intervals and studying the correlationbetween the flux observed in optical and in X-rays. We then studied how thisclassification is related with stellar properties. Results. Starting from asample of 74 class III/transition disk (TD) stars observed with CoRoT anddetected with Chandra with more than 60 counts, we selected 16 stars whoseoptical and X-ray variability is anti-correlated, 11 correlated, and 17 wherethere is no correlation. The remaining stars did not fall in any of thesegroups. We interpreted the anti-correlated optical and X-ray variability astypical of spot-dominated sources, due to the rotational modulation ofphotospheric spots spatially coincident to coronal active regions, andcorrelated variability typical of faculae-dominated sources, where thebrightening due to faculae is dominant over the darkening due to spots.[Conclusions not shown in the pre-print]

astronomy and astrophysics

CSI2264: Simultaneous optical and X-ray variability in the pre-main  sequence stars of NGC2264. II: Photometric variability, magnetic activity,  and rotation in classIII objects and stars with transition disks