# # Program information file # PROGRAM_ID 2024B051 PROGRAM_TITLE Multi-mission campaign to understand pulsed accretion and its effects on the circumbinary disk of DQ Tau PROGRAM_INV1 Agnes Kospal PROGRAM_INV2 Peter Abraham PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Planet-forming disks are no longer thought of as static structures. The mass accretion from the disk is highly variable, and the changing X-ray, UV, and optical radiation may have profound effects on the physical and chemical properties of the disk, right when planetary cores are being assembled or when planets are accreting their primary atmospheres. DQ Tau, thanks to its periodically changing accretion rate modulated by a central close eccentric binary, provides a unique opportunity for a systematic study on disk variability. This system's X-ray, UV, optical, and NIR brightness is known to increase during [almost] every periastron due to magnetic interactions and pulsed accretion. This proposal is part of a campaign to monitor DQ Tau over three periastrons in 2025 Jan-Mar, when [among other facilities] JWST will measure the variability of molecular emission features in the disk with MIRI MRS. Here, we propose a contemporaneous NIR spectroscopic monitoring of DQ Tau to follow how the near-infrared SED shape and the accretion rate change over time. We will use the SpeX/SXD to cover several important accretion rate tracer emission lines. Previous photometric and spectroscopic monitoring shows that not every periastron of the 15.8-day period binary displays the same variability and smaller accretion flares may also occur between periastrons. Therefore, we propose a nightly monitoring to follow the accretion evolution of the system with the best possible cadence. We plan to cover three consecutive periastrons in the 2025-Jan-20 - 2025-Mar-07 time period, 12 nights in semester 2024B, and 35 nights in semester 2025A. Each night, we will take 40 minutes [including overheads] to obtain a 0.7-2.5 um spectrum with S/N of ~ 100. The proposed project will provide the most detailed dynamical view of the accretion process and the inner part of the planet-forming disk around a T Tauri star. PROGRAM_ABSTRACT_END