Revealing the Star–Disk–Jet Connection in GM Aur Using Multiwavelength Variability

Abstract

Abstract We analyze the first simultaneous X-ray, ultraviolet, optical, infrared, and centimeter observations of a T Tauri star (TTS). We present three epochs of simultaneous Spitzer and Very Large Array data of GM Aur separated by ∼1 week. These data are compared to previously published Hubble Space Telescope and Chandra observations from which mass accretion rates ( ) and X-ray luminosities, respectively, were measured. The mid-infrared (MIR) emission increases along with , and we conclude that this is due to an increase in the mass in the inner disk. The centimeter emission, which probes the jet, also appears to increase as increases, and the changes in the centimeter flux are consistent with the variability in assuming the mass-loss rate is ∼10% . The 3 cm emission morphology also appears changed compared with observations taken three years previously, suggesting that for the first time, we may be tracking changes in the jet morphology of a TTS. The X-ray luminosity is constant throughout the three epochs, ruling out variable high-energy stellar radiation as the cause for the increases in the MIR or centimeter emission. Tying together the multiwavelength variability observed, we conclude that an increase in the surface density in the inner disk resulted in more mass loading onto the star and therefore a higher , which led to a higher mass-loss rate in the jet. These results stress the importance of coordinated multiwavelength work to better understand the star–disk–jet connection.