Quiescent X-ray Emission from an Evolved Brown Dwarf ?
نویسنده
چکیده
I report on the X-ray detection of Gl 569 Bab. During a 25 ksec Chandra observation the binary brown dwarf is for the first time spatially separated in X-rays from the flare star primary Gl 569 A. Companionship to Gl 569 A constrains the age of the brown dwarf pair to 300 − 800 Myr. The observation presented here is only the second X-ray detection of an evolved brown dwarf. About half of the observing time is dominated by a large flare on Gl 569 Bab, the remainder is characterized by weak and non-variable emission just above the detection limit. This emission – if not related to the afterglow of the flare – represents the first detection of a quiescent corona on a brown dwarf, representing an important piece in the puzzle of dynamos in the sub-stellar regime. Subject headings: X-rays: stars, Stars: coronae, flare, brown-dwarfs, individual (Gl569Bab)
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