Name/Affiliation: Sarah Margaret Smith (Northern Arizona University/Lowell Observatory)
A Near-Simultaneous Calibration of Near-Infrared Accretion Indicators for Classical T Tauri Stars
Classical T-Tauri Stars are cool, young stars surrounded by disks of dust and gas. Material from the inner disk is channeled along magnetic field lines onto the central star with in-fall rates that can vary on timescales as short as hours. Near-infrared (NIR) hydrogen lines are particularly useful accretion diagnostics for the youngest, most heavily extinguished young stars, but these features have primarily been calibrated using non-simultaneous measurements of excess continuum emission at ultraviolet (UV) wavelengths. We present Paß, Pa?, Pad and Br? line strengths for 71 classical T-Tauri stars, which we have calibrated against accretion luminosities measured by Herczeg & Hillenbrand from near-simultaneous ultra-violet/optical spectra (separation time < ~1 hour). We compare our new calibrations to those previously reported in the literature, while giving particular attention to the residuals of the linear fits to quantify the effects of using non-simultaneous data to calibrate the NIR indicators.