Trigonometric distance and proper motions of H ₂ O maser bowshocks in AFGL 5142

Abstract

We present the results of multi-epoch VLBI observations of water masers in the AGFL 5142 massive star forming region. We measure an annual parallax of π = 0.467 ± 0.010 mas, corresponding to a source distance of D = 2.14 +0.051 −0.049 kpc. Proper motion and line of sight velocities reveal the 3D kinematics of masers in this region, most of which associate with millimeter sources from the literature. In particular we find remarkable bipolar bowshocks expanding from the most massive member, AFGL 5142 MM1, which are used to investigate the physical properties of its protostellar jet. We attempt to link the known outflows in this region to possible progenitors by considering a precessing jet scenario and we discuss the episodic nature of ejections in AFGL 5142.

VLBI observations of the G25.65+1.05 water maser superburst

“…This propagation would traverse with a proper motion µ crosspoint = µ relative /tan θ where θ is the angle between the sheets and µ relative is their relative proper motion. Water masers in shocks typically move at about v ∼ 20 km s −1 (Burns et al 2016(Burns et al , 2017 which at distances of 2.7 and 12.5 kpc, and holding one sheet stationary, corresponds to relative proper a motion of µ relative ∼ 0.3 − 1.5 mas yr −1 . For θ ∼ 20°in VLA 1 we estimate that the crosspoint in the maser sheets would propagate in the skyplane at µ crosspoint ∼ 0.8−4.1 mas yr −1 .…”

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

“…Direct accurate distances and proper motions have been measured for maser-bearing young stars (e.g. Sanna et al 2014;Burns et al 2017); this data was obtained employing Very Long Baseline Interferometry (VLBI). This astrometric information has provided us with a better understanding of the Milky Way's spiral structure, insights into the formation and evolution of our Galaxy, its 3D gravitational potential, and the Galactic baryonic and dark matter distribution (Efremov 2011).…”

Studies of stellar evolution using masers

“…The VLBI Exploration of Radio Astrometry interferometer (VERA) is widely used as a distance estimator to maser sources and studying their kinematics. An example is the HMSFR AFGL 5142 with a 2.14 kpc (±2%) distance measured via the trigonometric parallax method and the same data reveal remarkable bipolar bowshocks expanding from the most massive member [8].…”