Separating the X‐Ray Emissions of UV Ceti A and B with Chandra

Abstract

We present the first spatially separated X-ray observation of the active UV Ceti binary with Chandra, providing important new information on the relative X-ray activity levels of its nearly identical dM5.5e components. The two components had similar X-ray luminosities during low-level periods, and emission measure loci derived from Low Energy Transmission Grating spectra reveal similar coronal temperatures (3-6 MK). However, the B component showed a higher degree of variability, resulting in a higher average X-ray luminosity than that of UV Cet A. We discuss possible causes of this enhanced activity in UV Cet B.