Magnetically Active Stars in Taurus-Auriga: Activity and Rotation

TL;DR

This study investigates magnetic activity and rotation in 70 stars in Taurus-Auriga, revealing saturation of X-ray luminosity, a correlation between lithium line strength and age, and evolution of magnetic field complexity.

Contribution

It provides new insights into the magnetic activity, rotation, and magnetic field evolution of pre-main-sequence stars in Taurus-Auriga.

Findings

Stars are in the saturated dynamo regime with maximum X-ray luminosity.

A correlation exists between lithium line equivalent width and stellar age.

Younger stars exhibit higher photometric activity than older stars.

Abstract

A sample of 70 magnetically active stars toward the Taurus-Auriga star-forming region has been investigated. The positions of the sample stars on the Rossby diagram have been analyzed. All stars are shown to be in the regime of a saturated dynamo, where the X-ray luminosity reaches its maximum and does not depend on the Rossby number. A correlation has been found between the lithium line equivalent width and the age of a solar-mass (from 0.7 to 1.2 Msun) pre-main-sequence star. The older the age, the smaller the Li line equivalent width. Analysis of the long-term photometric variability of these stars has shown that the photometric activity of the youngest stars is appreciably higher than that of the older objects from the sample. This result can be an indirect confirmation of the evolution of the magnetic field in pre-main-sequence stars from predominantly dipole and axisymmetric to multipole and nonaxisymmetric.