Coronal X-ray emission from an intermediate-age brown dwarf
Abstract
We report the X-ray detection of the brown dwarf (BD) companion TWA 5B in a Myr old pre-main sequence binary system. We clearly resolve the faint companion (35 photons) separated from the X-ray luminous primary by 2 arcsec in a {\it Chandra} ACIS image. TWA 5B shows a soft X-ray spectrum with a low plasma temperature of only 0.3 keV and a constant flux during the 3 hour observation, of which the characteristics are commonly seen in the solar corona. The X-ray luminosity is 4 erg s (0.1--10 keV band) or . Comparing these properties to both younger and older BDs, we discuss the evolution of the X-ray emission in BDs. During their first few Myr, they exhibit high levels of X-ray activity as seen in higher mass pre-main sequence stars. The level in TWA 5B is still high at Myr in while has already substantially cooled.
Cite
@article{arxiv.astro-ph/0304231,
title = {Coronal X-ray emission from an intermediate-age brown dwarf},
author = {Yohko Tsuboi and Yoshitomo Maeda and Eric D. Feigelson and Gordon P. Garmire and George Chartas and Koji Mori and Steven H. Pravdo},
journal= {arXiv preprint arXiv:astro-ph/0304231},
year = {2009}
}