Methanol and water maser observations separate disc and outflow sources in IRAS 19410+2336

TL;DR

This study uses high-resolution maser observations to distinguish between disc and outflow structures in a high-mass star-forming region, revealing complex kinematics and spatial distributions.

Contribution

First astrometric measurements at 6.7 GHz in IRAS 19410+2336, providing detailed maser distributions that differentiate outflow and disc components.

Findings

Methanol masers trace outflows from mm1

Water masers indicate a disc around 13-s

Estimated enclosed mass between 11 and 44 solar masses

Abstract

We investigate the kinematics of high mass protostellar objects within the high mass star forming region IRAS 19410+2336. We performed high angular resolution observations of 6.7-GHz methanol and 22 GHz water masers using the MERLIN (Multi-Element Radio Linked Interferometer Network) and e-MERLIN interferometers. The 6.7-GHz methanol maser emission line was detected within the $\sim$ 16--27 km s$^{-1}$ velocity range with a peak flux density $\sim$50 Jy. The maser spots are spread over $\sim$1.3 arcsec on the sky, corresponding to $\sim$2800 au at a distance of 2.16 kpc. These are the first astrometric measurements at 6.7 GHz in IRAS 19410+2336. The 22-GHz water maser line was imaged in 2005 and 2019 (the latter with good astrometry). Its velocities range from 13 to $\sim$29 km s$^{-1}$. The peak flux density was found to be 18.7 Jy and 13.487 Jy in 2005, and 2019, respectively. The distribution of the water maser components is up to 165 mas, $\sim$350 au at 2.16 kpc. We find that the Eastern methanol masers most probably trace outflows from the region of millimetre source mm1. The water masers to the West lie in a disc (flared or interacting with outflow/infall) around another more evolved millimetre source (13-s). The maser distribution suggests that the disc lies at an angle of 60$^{\circ}$ or more to the plane of the sky and the observed line of sight velocities then suggest an enclosed mass between 44 M$_{\odot}$ and as little as 11 M$_{\odot}$ if the disc is edge-on. The Western methanol masers may be infalling.