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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Magnetic activity and rotation are related to the age of low-mass mainsequence stars. To further constrain these relations, we study a sample of 574main sequence stars members of common proper motion pairs with white dwarfs,identified thanks to Gaia astrometry. We use the white dwarfs as ageindicators, while the activity indexes and rotational velocities are obtainedfrom the main sequence companions using standard procedures. We find that starsolder than 5 Gyr do not display Halpha nor Caii H&K emission unless they arefast rotators due to tidal locking from the presence of unseen companions andthat the rotational velocities tend to decrease over time, thus supporting theso-called gyrochronology. However, we also find moderately old stars (~2-6 Gyr)that are active presumably because they rotate faster than they should fortheir given ages. This indicates that they may be suffering from weakenedmagnetic braking or that they possibly evolved through wind accretion processesin the past. The activity fractions that we measure for all stars younger than5 Gyr range between ~10-40 per cent. This is line with the expectations, sinceour sample is composed of F, G, K and early M stars, which are thought to haveshort (<2 Gyr) activity lifetimes. Finally, we observe that the Halphafractional luminosities and the R'HK indexes for our sample of (slowlyrotating) stars show a spread (-4>log(LHalpha/Lbol); log(R'HK)> -5) typicallyfound in inactive M stars or weakly active/inactive F, G, K stars.

Main sequence companions to white dwarfs II: the age-activity-rotation relation from a sample of Gaia common proper motion pairs