Dense Cores, Filaments and Outflows in the S255IR Region of High Mass Star Formation

Abstract

We investigate at a high angular resolution the spatial and kinematic structure of the S255IR high mass star-forming region, which demonstrated recently the first disk-mediated accretion burst in the massive young stellar object. The observations were performed with ALMA in Band 7 at an angular resolution $\sim 0.1^{\prime \prime }$, which corresponds to $\sim 180$ AU. The 0.9 mm continuum, C${}^{34}$S(7-6) and CCH $N=4-3$ data show a presence of very narrow ($\sim 1000$ AU), very dense ($n\sim 10^7$ cm${}^{-3}$) and warm filamentary structures in this area. At least some of them represent apparently dense walls around the high velocity molecular outflow with a wide opening angle from the S255IR-SMA1 core, which is associated with the NIRS3 YSO. This wide-angle outflow surrounds a narrow jet. At the ends of the molecular outflow there are shocks, traced in the SiO(8-7) emission. The SiO abundance there is enhanced by at least 3 orders of magnitude. The CO(3-2) and SiO(8-7) data show a collimated and extended high velocity outflow from another dense core in this area, SMA2. The outflow is bent and consists of a chain of knots, which may indicate periodic ejections possibly arising from a binary system consisting of low or intermediate mass protostars. The C${}^{34}$S emission shows evidence of rotation of the parent core. Finally, we detected two new low mass compact cores in this area (designated as SMM1 and SMM2), which may represent prestellar objects.

15 pages, 14 figures, accepted by the Astrophysical Journal

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Cited by in corpus (14)

• ALMA View of the Infalling Envelope around a Massive Protostar in S255IR SMA1
• Parameter study for the burst mode of accretion in massive star formation
• Salt-bearing disk candidates around high-mass young stellar objects
• The sharpest view on the high-mass star-forming region S255IR. Near-InfraRed Adaptive Optics Imaging on the Outbursting Source NIRS3
• The disk-outflow system around the rare young O-type protostar W42-MME
• The burst mode of accretion in massive star formation with stellar inertia
• Ammonia mapping observations toward the Galactic massive star-forming region Sh 2-255 and Sh 2-257
• Fine structure and kinematics of the ionized and molecular gas in the jet and disk around S255IR NIRS3 from high resolution ALMA observations
• Ethynyl around the HII regions S255 and S257
• Structure and Kinematics of Sh2-138 -- A distant hub-filament system in the outer Galactic plane
• Spectral survey of a Hot core with an Eruptive Accretion in S255IR NIRS3 (SHEA): The discovery of class I and class II millimeter methanol maser transitions
• Study of the high-mass star-forming region S255IR at various scales
• ALMA discovery of a dual dense probably rotating outflow from a massive young stellar object G18.88MME
• Digging into the Massive Protostar S255IR NIRS3: A Study of Nitrogen-Bearing Molecules and Their Prebiotic Chemistry