论文信息 - 3D velocity fields from methanol and water masers in an intermediate-mass protostar

3D velocity fields from methanol and water masers in an intermediate-mass protostar

Abstract We report multi-epoch VLBI observations of molecular masers towards the high-mass star forming region AFGL 5142, leading to the determination of the 3D velocity field of circumstellar molecular gas at radii <0.″23 (or 400 AU) from the protostar MM–1. Our observations of CH3OH maser emission enabled, for the first time, a direct measurement of infall of a molecular envelope on to an intermediate-mass protostar (radius of 300 AU, velocity of 5 km s−1, and infall rate of 6 × 10−4n8M⊙ yr−1, where n8 is the ambient volume density in units of 108 cm−3). In addition, our measurements of H2O maser (and radio continuum) emission revealed a collimated bipolar molecular outflow (and ionized jet) from MM–1. The evidence of simultaneous accretion and outflow at small spatial scales, makes AFGL 5142 an extremely compelling target for high-angular resolution studies of high-mass star formation.

C. Goddi | A. Sanna | L. Moscadelli

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