Observations of the T Tauri spectroscopic binary DQ Tau in April 2008 captured an unusual flare at 3 mm , which peaked at an observed maximum flux of \sim 0.5 Jy ( about 27 times the quiescent value ) .
Here we present follow-up millimeter observations that demonstrate a periodicity to the phenomenon .
While monitoring 3 new periastron encounters , we have detected flares within 17.5 hours ( or 4.6 % ) of the orbital phase of the first reported flare and constrained the main emitting region to a stellar height of 3.7–6.8 R _ { \star } .
The recorded activity is consistent with the proposed picture for synchrotron emission initiated by a magnetic reconnection event when the two stellar magnetospheres of the highly eccentric ( e = 0.556 ) binary are believed to collide near periastron as the stars approach a minimum separation of 8 R _ { \star } ( \sim 13 R _ { \odot } ) .
The similar light curve decay profiles allow us to estimate an average flare duration of 30 hours .
Assuming one millimeter flare per orbit , DQ Tau could spend approximately 8 % of its 15.8-day orbital period in an elevated flux state .
These findings continue to serve as a small caution for millimeter flux points in spectral energy distributions that could contain unrecognized flare contributions .
Our analysis of the millimeter emission provides an upper limit of 5 % on the linear polarization .
We discuss the extent to which a severely entangled magnetic field structure and Faraday rotation effects are likely to reduce the observed polarization fraction .
We also predict that , for the current picture , the stellar magnetospheres must be misaligned at a significant angle or , alternatively , that the topologies of the outer magnetospheres are poorly described by a well-ordered dipole inside a radius of 7 R _ { \star } .
Finally , to investigate whether reorganization of the magnetic field during the interaction affects mass accretion , we also present simultaneous optical ( VRI ) monitoring of the binary , as an established tracer of accretion activity in this system .
We find that an accretion event can occur coincident in both time and duration with the synchrotron fallout of a magnetic reconnection event .
While the pulsed accretion mechanism has been attributed previously to the dynamical motions of the stars alone , the similarities between the millimeter and optical light curves evoke the possibility of a causal or co-dependent relationship between the magnetospheric and dynamical processes .