Discovery of a Highly Collimated Flow from the High-Mass Protostar ISOSS J23053+5953 SMM2

TL;DR

This study reports the discovery of a highly collimated, massive outflow from a high-mass protostar, using multi-wavelength observations that reveal its early evolutionary stage and outflow characteristics.

Contribution

First detailed multi-wavelength observation of a highly collimated outflow from a high-mass protostar, confirming its early evolutionary phase and outflow properties.

Findings

Detected a fast, highly collimated outflow with velocities over 50 km/s.

Estimated the SMM2 core mass at 45.8 solar masses.

Found CO depletion by a factor of about 20, indicating freeze-out on dust grains.

Abstract

We present Very Large Array C, X, and Q-band continuum observations, as well as 1.3 mm continuum and CO(2-1) observations with the Submillimeter Array toward the high-mass protostellar candidate ISOSS J23053+5953 SMM2. Compact cm continuum emission was detected near the center of the SMM2 core with a spectral index of 0.24 between 6 and 3.6 cm, and a radio luminosity of 1.3 mJy kpc$^2$. The 1.3 mm thermal dust emission indicates a mass of the SMM2 core of 45.8 Msun. The CO(2-1) observations reveal a large, massive molecular outflow centered on the SMM2 core. This fast outflow ($>$ 50 km/s from the cloud systemic velocity) is highly collimated, with a broader, lower-velocity component. The large values for outflow mass (45.2 Msun), and momentum rate (6 x 10$^{-3}$ Msun km/s/yr) derived from the CO emission are consistent with those of flows driven by high-mass YSOs. The dynamical timescale of the flow is between 1.5 - 7.2 x 10$^4$ yr. We also found from the C18O to thermal dust emission ratio that CO is depleted by a factor of about 20, possibly due to freeze out of CO molecules on dust grains. Our data are consistent with previous findings that ISOSS J23053+5953 SMM2 is an emerging high-mass protostar in an early phase of evolution, with an ionized jet, and a fast, highly collimated, and massive outflow.