Soft coronal X-rays from \beta{} Pictoris

TL;DR

This study detects faint X-ray emission from the A5 V star eta Pictoris, suggesting it has a cool, dim corona similar to cooler stars, challenging previous expectations of X-ray darkness in such stars.

Contribution

First detection of X-ray emission from eta Pictoris, revealing a cool corona and providing insights into stellar activity in A-type stars.

Findings

Detected X-ray flux of 9+-2 x 10^{-4} counts/s from eta Pictoris.

Identified a thermal emission component at around 1.1 MK.

Estimated X-ray to bolometric luminosity ratio of log L_X/L_{bol}=-8.2.

Abstract

A type stars are expected to be X-ray dark, yet weak emission has been detected from several objects in this class. We present new Chandra/HRC-I observations of the A5 V star \beta{} Pictoris. It is clearly detected with a flux of 9+-2 10^{-4} counts/s. In comparison with previous data this constrains the emission mechanism and we find that the most likely explanation is an optically thin, collisionally dominated, thermal emission component with a temperature around 1.1 MK. We interpret this component as a very cool and dim corona, with \log L_X/L_{bol}=-8.2 (0.2-2.0 keV). Thus, it seems that \beta{} Pictoris shares more characteristics with cool stars than previously thought.