A Submillimeter Burst of S255IR~SMA1 - The Rise And Fall Of Its Luminosity

TL;DR

This paper reports a transient luminosity burst in a high-mass star-forming region, observed as a rise and fall in submillimeter emission and methanol maser activity over two years, indicating episodic accretion events.

Contribution

It provides the first observational evidence of a submillimeter burst in a high-mass star-forming region, linking it to episodic accretion phenomena.

Findings

Submillimeter flux increased by a factor of ~2 during the burst.

The burst lasted approximately 2 years.

Methanol maser emission also intensified during the event.

Abstract

Temporal photometric variations at near infrared to submillimeter wavelengths have been found in low-mass young stellar objects. These phenomena are generally interpreted as accretion events of star-disk systems with varying accretion rates. There is growing evidence suggesting that similar luminosity flaring also occurs in high-mass star/cluster-forming regions. We report in this Letter the rise and fall of the 900 ${\mu}$m continuum emission and the newly found 349.1 GHz methanol maser emission in the massive star forming region S255IR~SMA1 observed with the Submillimeter Array and the Atacama Large Millimeter/submillimeter Array. The level of flux variation at a factor of $\sim$ 2 at the submillimeter band and the relatively short 2-year duration of this burst suggest that the event is probably similar to those milder and more frequent minor bursts seen in 3D numerical simulations.