First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259

TL;DR

This study presents the first parallax and proper motion measurements of a 6.7 GHz methanol maser using the Australian Long Baseline Array, accurately determining the distance to G339.884-1.259 and its association with a high-mass star.

Contribution

It provides the first parallax measurement of this maser source, refining its distance and confirming its location in the Scutum spiral arm.

Findings

Measured parallax of 0.48±0.08 mas, distance ~2.1 kpc

Consistent with kinematic distance estimates

Identified the embedded star as spectral type B1

Abstract

We have conducted the first parallax and proper motion measurements of 6.7 GHz methanol maser emission using the Australian Long Baseline Array (LBA). The parallax of G339.884$-$1.259 measured from five epochs of observations is 0.48$\pm $0.08 mas, corresponding to a distance of $2.1^{+0.4}_{-0.3}$ kpc, placing it in the Scutum spiral arm. This is consistent (within the combined uncertainty) with the kinematic distance estimate for this source at 2.5$\pm $0.5 kpc using the latest Solar and Galactic rotation parameters. We find from the Lyman continuum photon flux that the embedded core of the young star is of spectral type B1, demonstrating that luminous 6.7 GHz methanol masers can be associated with high-mass stars towards the lower end of the mass range.