Pre- and Post-burst Radio Observations of the Class 0 Protostar HOPS 383 in Orion

TL;DR

This study investigates the radio emission behavior of the Class 0 protostar HOPS 383 during an accretion burst, finding little radio variability and suggesting accretion and ejection are not tightly coupled on short timescales.

Contribution

It provides the first radio observational constraints on a protostar experiencing a significant accretion burst, challenging assumptions about the timing of accretion and ejection events.

Findings

Radio flux remained stable at 200-300 μJy over 16 years.

No radio burst detected during the accretion outburst.

Accretion and ejection enhancements may not be synchronized on short timescales.

Abstract

There is increasing evidence that episodic accretion is a common phenomenon in Young Stellar Objects (YSOs). Recently, the source HOPS 383 in Orion was reported to have a $\times 35$ mid-infrared -- and bolometric -- luminosity increase between 2004 and 2008, constituting the first clear example of a class 0 YSO (a protostar) with a large accretion burst. The usual assumption that in YSOs accretion and ejection follow each other in time needs to be tested. Radio jets at centimeter wavelengths are often the only way of tracing the jets from embedded protostars. We searched the Very Large Array archive for the available observations of the radio counterpart of HOPS 383. The data show that the radio flux of HOPS 383 varies only mildly from January 1998 to December 2014, staying at the level of $\sim 200$ to 300 $\mu$Jy in the X band ($\sim 9$ GHz), with a typical uncertainty of 10 to 20 $\mu$Jy in each measurement. We interpret the absence of a radio burst as suggesting that accretion and ejection enhancements do not follow each other in time, at least not within timescales shorter than a few years. Time monitoring of more objects and specific predictions from simulations are needed to clarify the details of the connection betwen accretion and jets/winds in YSOs.