# Identifying Variability in Deeply Embedded Protostars with ALMA and CARMA

## TL;DR

This study investigates brightness variability in deeply embedded protostars using ALMA and CARMA data over nine years, finding no significant changes but suggesting future observations could detect smaller fluctuations.

## Contribution

The paper introduces novel methods for comparing interferometric observations and demonstrates their application to protostar variability analysis.

## Key findings

- No brightness variation above 50% detected in the data
- CARMA's limited sensitivity constrained variability detection
- Future ALMA observations could reveal variability at a few percent level

## Abstract

Variability of pre-main-sequence stars observed at optical wavelengths has been attributed tofluctuations in the mass accretion rate from the circumstellar disk onto the forming star.Detailed models of accretion disks suggest that young deeply embedded protostars should also exhibit variations in their accretion rates, and that these changes can be tracked indirectly by monitoring the response of the dust envelope at mid-IR to millimeter wavelengths. Interferometers such as ALMA offer the resolution and sensitivity to observe small fluctuations in brightness at the scale of the disk where episodic accretion may be driven. In this work, we present novel methods for comparing interferometric observations and apply them to CARMA and ALMA 1.3mm observations of deeply embedded protostars in Serpens taken 9 years apart. We find no brightness variation above the limits of our analysis of a factor of $\gtrsim 50\%$, due to the limited sensitivity of the CARMA observations and small number of sources common to both epochs. We further show that follow up ALMA observations with a similar sample size and sensitivity may be able to uncover variability at the level of a few percent, and discuss implications for future work.