2004ApJ...615L.153S

I report on the X-ray detection of Gl 569Bab. During a 25 ks Chandra observation, the binary brown dwarf is for the first time spatially separated in X-rays from the flare star primary Gl 569A. Companionship to Gl 569A 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 569Bab; the remainder is characterized by weak and nonvariable 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 substellar regime.