  DQ Tau is a unique young high-eccentricity binary system that exhibits
regular magnetic reconnection flares and pulsed accretion near periastron. We
conducted NuSTAR, Swift, and Chandra observations during the July 30, 2022
periastron to characterize X-ray, near-ultraviolet (NUV), and optical flaring
emissions. Our findings confirm the presence of X-ray super-flares accompanied
by substantial NUV and optical flares, consistent with previous discoveries of
periastron flares in 2010 and 2021. These observations, supported by new
evidence, strongly establish the magnetosphere collision mechanism as the
primary driver of magnetic energy release during DQ Tau's periastron flares.
The energetics of the observed X-ray super-flares remain consistent across the
three periastrons, indicating recurring energy sources during each passage,
surpassing the capabilities of single stars. The observed flaring across
multiple bands supports the Adams et al. model for magnetosphere interaction in
eccentric binaries. Evidence from modeling and past and current observations
suggests that both the mm/X-ray periastron flares and tentatively, the magnetic
reconnection-related components of the optical/NUV emissions, conform to the
classical solar/stellar non-thermal thick-target model, except for the
distinctive magnetic energy source. However, our NuSTAR observations suffered
from high background levels, hindering the detection of anticipated non-thermal
hard X-rays. Furthermore, we report serendipitous discovery of X-ray
super-flares occurring away from periastron, potentially associated with
interacting magnetospheres. The current study is part of a broader
multi-wavelength campaign, which is planned to investigate the influence of DQ
Tau's stellar radiation on gas-phase ion chemistry within its circumbinary
disk.
