2024/01/05 by Tatiana M. Rodríguez, Rodriguez, Tatiana M., Emmanuel Momjian +7
Physics and Astronomy · #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #Astro and Planetary Science
paper · pdf · doi:10.48550/arxiv.2401.03049
We present Very Large Array (VLA) 1.3 cm continuum and 22.2 GHz H2O maser observations of the high-mass protostellar object IRAS 19035+0641 A. Our observations unveil an elongated bipolar 1.3 cm continuum structure at scales \lesssim500 au which, together with a rising in-band spectral index, strongly suggests that the radio emission toward IRAS 19035+0641 A arises from an ionized jet. In addition, eight individual water maser spots well aligned with the jet axis were identified. The Stokes V spectrum of the brightest H2O maser line (∼100 Jy) shows a possible Zeeman splitting and is well represented by the derivatives of two Gaussian components fitted to the Stokes I profile. The measured Blos are 123 (±27) and 156 (±8) mG, translating to a pre-shock magnetic field of ≈7 mG. Subsequent observations to confirm the Zeeman splitting showed intense variability in all the water maser spots, with the brightest maser completely disappearing. The observed variability in a one-year time scale could be the result of an accretion event. These findings strengthen our interpretation of IRAS 19035+0641 A as a high-mass protostar in an early accretion/outflow evolutionary phase.