Presentation #406.13 in the session Young Stellar Objects and T Tauri Stars — iPoster Session.
Young (~2 Myr), roughly solar mass stars are known to be very magnetically active. These T Tauri stars typically display mean surface magnetic field strengths of 2–2.5 kG. To date, little is known about the variability of the magnetic fields on these stars, though strong photometric variability of weak-lined (diskless, non-accreting) T Tauri stars on rotational timescales indicates that large spots are present on their surface which may then produce magnetic field strength variability on similar timescales. Longer timescale variations in the field may result from the dynamo process that produces the strong fields in the first place. In order to explore the amplitude and timescale of magnetic field variability on T Tauri stars, we analyze time series of high resolution (R ~ 45,000) K band spectra obtained with the IGRINS spectrometer of the weak-lined star V830 Tau and the classical (accreting) T Tauri star CI Tau. Over approximately 4.5 years, we obtained 86 nights of data on V830 Tau and 70 nights of data on CI Tau. These two stars are of particular interest as both are suspected of hosting newly formed hot Jupiters in orbit around them. We use magnetically sensitive Ti I lines in the K band to determine the mean magnetic field on the surface for each night of observation. We then analyze the resulting time series of magnetic field measurements and characterize the field variability on these young stars.