SiO v = 1 J = 5 → 4 Maser Emission from the Root of the “Water Fountain” Source W 43A
Journal article, 2025

We report here the first mapping of SiO v = 1 J = 5 → 4 maser emission toward the “water fountain” source W 43A in order to explore the central stellar system driving the collimated, bipolar, fast jet. The maser source has a systemic line-of-sight velocity consistent with that of CO J = 2 → 1 emission tracing the jet within ∼2 km s−1 but a velocity gradient opposite that of the jet. The dynamical center of the maser source is located within ∼10 mas (or ∼20 au) of the brightness peak of the central 1.3 mm continuum emission. The spatiokinematic properties of the SiO J = 5 → 4 and J = 1 → 0 masers suggest that they are associated with the root of a slow (10 km s−1 < Voutflow << 100 km s−1) outflow with a large opening angle, and the central stellar system is contained within the inner maser region (∼20 au) during a possible common-envelope evolution.

Author

H. Imai

Kagoshima University

Takeshi Hoshino

Kagoshima University

Daniel Tafoya

Chalmers, Space, Earth and Environment, Onsala Space Observatory

J. F. Gomez

Spanish National Research Council (CSIC)

Jun Ichi Nakashima

Sun Yat-Sen University

G. Orosz

Joint Institute for VLBI in Europe (JIVE)

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 987 2 114

Subject Categories (SSIF 2025)

Fusion, Plasma and Space Physics

Astronomy, Astrophysics, and Cosmology

Meteorology and Atmospheric Sciences

DOI

10.3847/1538-4357/adde4e

More information

Latest update

7/15/2025