Mid-infrared (mid-IR) variability in young stellar objects (YSOs) is driven by several physical mechanisms that lead to a variety of amplitudes and light curve shapes. An important mechanism to drive secular variability is likely variable disk accretion rates, as predicted by the episodic accretion model. In an analysis of 6.5 yr of mid-IR NeoWISE light curves (3-5 microns) of ~7000 nearby YSOs, Park et al. (2021) found an increase in the fraction of variability and variability amplitude towards objects at younger stages of evolution. With the aim of determining the likely physical mechanism driving the variability in the sample of nearby YSOs, our group obtained low- and high-resolution near-IR spectra of 78 YSOs in the sample of Park et al. (2021). In this work we present the analysis of nine nearby YSOs (d<1 kpc) that show characteristics of known classes of eruptive variable YSOs. We find one FUor-like source, one EX Lupi-type object and six YSOs with mixed characteristics, or V1647 Ori-like objects. The varied characteristics observed in our sample are consistent with recent discoveries of eruptive YSOs. The wide range in YSO outburst parameters (central mass, maximum accretion rate during outburst, evolutionary stage and/or instability leading to the outburst) may play a significant role in the observed spectro-photometric characteristics of YSO outbursts. Adding new objects to the YSO eruptive variable class aids our understanding of the episodic accretion phenomenon and its possible impact on stellar and planetary formation.
[Poster PDF File]