VLA observations of candidate high-mass protostellar objects at 7 mm

TL;DR

This study uses 7 mm radio observations with the VLA to detect and analyze ionized gas in three early-stage high-mass star-forming regions, revealing hypercompact ionized regions indicative of very young massive protostars.

Contribution

First high-resolution 7 mm VLA observations of candidate high-mass protostellar objects, identifying hypercompact ionized regions in early star formation stages.

Findings

Detected 7 mm emission in all three sources.

All emissions are from thermal ionized gas.

IRAS 19217+1651 and IRAS 23151+5912 have hypercompact ionized regions.

Abstract

We present radio continuum observations at 7 mm made using the Very Large Array towards three massive star forming regions thought to be in very early stages of evolution selected from the sample of Sridharan et al. (2002). Emission was detected towards all three sources (IRAS 18470-0044, IRAS 19217+1651 and IRAS 23151+5912). We find that in all cases the 7 mm emission corresponds to thermal emission from ionized gas. The regions of ionized gas associated with IRAS 19217+1651 and IRAS 23151+5912 are hypercompact with diameters of 0.009 and 0.0006 pc, and emission measures of 7.0 x 10^8 and 2.3 x 10^9 pc cm^(-6), respectively.