# Initial phases of high-mass star formation: A multiwavelength study towards the extended green object G12.42+0.50

## TL;DR

This multiwavelength study investigates the early stages of high-mass star formation in G12.42+0.50, revealing a complex environment with an UC H II region, ionized jet, massive cold dust clump, and signs of infall and outflow activity.

## Contribution

It provides a detailed multiwavelength analysis of G12.42+0.50, highlighting the coexistence of an UC H II region, ionized jet, and hub-filament structure in an early massive star formation stage.

## Key findings

- Detection of an UC H II region and ionized thermal jet.
- Massive cold dust clump of 1375 solar masses.
- Evidence of infall and outflow activities.

## Abstract

We present a multiwavelength study of the extended green object, G12.42+0.50 in this paper. The associated ionized, dust, and molecular components of this source are studied in detail employing various observations at near-, mid- and far-infrared, submillimeter and radio wavelengths. Radio continuum emission mapped at 610 and 1390 MHz, using the Giant Meterwave Radio Telescope, India, advocates for a scenario of coexistence of an UC H II region and an ionized thermal jet possibly powered by the massive young stellar object, IRAS 18079-1756 with an estimated spectral type of B1 - B0.5. Shock-excited lines of H2 and [FeII], as seen in the near-infrared spectra obtained with UKIRT-UIST, lend support to this picture. Cold dust emission shows a massive clump of mass 1375 M{\sun} enveloping G12.42+0.50. Study of the molecular gas kinematics using the MALT90 and JCMT archival data unravels the presence of both infall activity and large-scale outflow suggesting an early stage of massive star formation in G12.42+0.50. A network of filamentary features are also revealed merging with the massive clump mimicking a hub-filament layout. Velocity structure along these indicate bulk inflow motion.