5/29/25

 The variables identified in this study are listed in Table [tsr: Table doesn’t exist yet].35
A map of their positions, and an H-R diagram showing their colors and magnitudes, is shown in Figure(s) [tsr:36
Figures don’t exist yet].

5/28/25

 We identified variables using the following methods.21
1. the Stetson variability index (P. Stetson 1996);22
2. reduced chi-squared (χ2
ν );23
3. the Lomb-Scargle periodogram (N. R. Lomb 1976; J. D. Scargle 1982; J. T. VanderPlas 2018).24
Objects were identified as variable if they met any of the following three criteria:25
1. the ”automatic Stetson” criterion: its light curve was high signal-to-noise, free from major photometric processing26
error flags, and showed a Stetson index exceeding the 99.7th percentile (a ”three-sigma” equivalent) for its27
magnitude range;28
2. the ”periodic” criterion: the object was identified as a periodic variable;29
3. the ”subjective” criterion: the object was in neither of the above two groups, but had a χ2
ν in at least one30
band consistent with variability, and upon manual inspection, displayed a light curve which showed unambigu-31
ous correlated variability across multiple bands that was not purely stochastic and could not be produced by32
photometric processing errors or artifacts.

5/26/25

 We looked at the star forming regions NGC 1333 and IC 348 for 6+ months each. It was with UKIRT, using the WCFAM instrument, monitoring in J, H, and K. In our monitoring of 539 stellar
and substellar cluster members with spectral types from M0-L3, we have identified 265 variables,
including 143 periodic variables

10/10/24

 We used the Lomb-Scargle Periodogram (as implemented by astropy) to search for periodic signals in each band of all 539 stars' light curves.
Each such light curve was analyzed in three ways:
\begin{itemize}
    \item unmodified;
    \item detrended with a second-order polynomial;
    \item detrended with a fourth-order polynomial.
\end{itemize}
Objects that had a false-alarm probability of $10^{-5}$ or smaller\footnote{Details of how the threshold of $10^{-5}$ was chosen are given in the Appendix.} in any band under any detrending method were selected as `periodic candidates`.
Each periodic candidate was further analyzed by inspection of all periodograms and all folded light curves.
Whenever a clear `best` period was identified via this approach (often by looking for some consensus between bands and/or methods), we identified a period and flagged the object as a periodic variable.
\tsr{X number} of objects were thus identified as periodic variables.

4/14/22

 Variable stars are selected via two methods: their periodicity (via
the Lomb-Scargle periodogram) and their general variability (via
the Stetson variability index). We identified variable stars using 3
criteria:
(i) an automated Stetson selection;
(ii) a periodic selection using the Lomb-Scargle periodogram;
and
(iii) a manual selection of light curves with high Stetson indices
but with one or more photometric error flags in each band.
Each of these selections is elaborated upon in the following subsec-
tions. We have detected 244 variable objects out of 658 analyzed
targets.

7/30/21

From mid-infrared observations of YSOs, Young et al. (2015) support ages of∼2Myr for IC 348 and.1Myr for NGC 1333.

7/29/21

Our study comprises very low mass stars (.0.2푀) and browndwarfs (.0.08푀, i.e.,.80푀Jup) in three star-forming re-gions: the Orion Nebula Cluster (ONC), NGC 1333, and IC 348.Among young (∼1−3Myr) stars and brown dwarfs, mass is closelycorrelated with spectral type and effective temperature (푇eff); thehydrogen-burning limit of∼0.08푀corresponds to a spectral typeof∼M6 and an effective temperature of∼3000K (Luhman et al.2003; Luhman 2012). In the ONC, we rely on membership and푇effestimations from Robberto et al. (2020); in NGC 1333 and IC 348,we rely on membership and spectral type estimates from Luhmanet al. (2016).