2009ApJ...693L..86C

We present new 7 mm and archive 1.3 cm high angular resolution observations of the HL/XZ Tau region made with the Very Large Array. At 7 mm, the emission from HL Tau seems to arise in a clumpy disk with radius of the order of 25 AU. The 1.3 cm emission from XZ Tau shows the emission from a binary system with 0".3 (42 AU) separation, known from previous optical/IR observations. However, at 7 mm, the southern radio component resolves into a binary with 0".09 (13 AU) separation, suggesting that XZ Tau is actually a triple star system. We suggest that the remarkable ejection of gas from the XZ Tau system observed with the Hubble Space Telescope may be related to a periastron passage of this newly discovered close binary system.