We present 29 likely members of the young \rho Oph or Upper Sco regions of recent star formation that exhibit “ accretion burst ” type light curves in K 2 time series photometry .
The bursters were identified by visual examination of their \sim 80 day light curves , though all satisfy the M < -0.25 flux asymmetry criterion for burst behavior defined by Cody et al .
( 2014 ) .
The burst sources represent \approx 9 % of cluster members with strong infrared excess indicative of circumstellar material .
Higher amplitude burster behavior is correlated with larger inner disk infrared excesses , as inferred from WISE W 1 - W 2 color .
The burst sources are also outliers in their large H \alpha emission equivalent widths .
No distinction between bursters and non-bursters is seen in stellar properties such as multiplicity or spectral type .
The frequency of bursters is similar between the younger , more compact \rho Oph region , and the older , more dispersed Upper Sco region .
The bursts exhibit a range of shapes , amplitudes ( \sim 10-700 % ) , durations ( \sim 1-10 days ) , repeat time scales ( \sim 3-80 days ) , and duty cycles ( \sim 10-100 % ) .
Our results provide important input to models of magnetospheric accretion , in particular by elucidating the properties of accretion-related variability in the low state between major longer duration events such as EX Lup and FU Ori type accretion outbursts .
We demonstrate the broad continuum of accretion burst behavior in young stars – extending the phenomenon to lower amplitudes and shorter timescales than traditionally considered in the theory of pre-main sequence accretion history .