Mid-infrared Variability and Mass Accretion Toward NGC 2264 Protostars
Abstract
Variable mass accretion has been suggested to be an important aspect of protostar formation. Mid-infrared wavelength observations trace variations in accretion luminosity and thus can probe mass accretion on sub-AU scales. We present results from the Spitzer YSOVAR campaign towards class I protostars in NGC 2264. The precise (0.02 mag) medium-cadence light curves at 3.6 and 4.5 microns show that young star variability is ubiquitous, with a variety of morphologies and time scales. A structure function analysis shows the light curves, on average, have a power-law behavior up to 30 days. The trend continues to longer timescales (years) for protostars (class I), in contrast with the smaller brightness changes displayed by T Tauri stars (class II). The power-law behavior suggests a stochastic process such as turbulent mass accretion drives the variability. We discuss theoretical models and the prospects for determining mass accretion rates from synoptic studies.
- Publication:
-
IAU General Assembly
- Pub Date:
- August 2015
- Bibcode:
- 2015IAUGA..2257989T