Hot methanol from the inner region of the HH 212 protostellar system

Abstract

The mechanisms leading to the formation of disks around young stellar objects (YSOs) and to the launching of the associated jets are crucial to the understanding of the earliest stages of star and planet formation. HH 212 is a privileged laboratory to study a pristine jet-disk system. Therefore we investigate the innermost region ($<100$ AU) around the HH 212-MM1 protostar through ALMA band\,7 observations of methanol. The 8 GHz bandwidth spectrum towards the peak of the continuum emission of the HH 212 system reveals at least 19 transitions of methanol. Several of these lines (among which several vibrationally excited lines in the v${}_{\mathrm{t}}=1,2$ states) have upper energies above 500 K. They originate from a compact ($<135$ AU in diameter), hot ($\sim 295$ K) region elongated along the direction of the SiO jet. We performed a fit in the $uv$ plane of various velocity channels of the strongest high-excitation lines. The blue- and red-shifted velocity centroids are shifted roughly symmetrically on either side of the jet axis, indicating that the line-of-sight velocity beyond 0.7 km s${}^{-1}$ from systemic is dominated by rotational motions. The velocity increases moving away from the protostar further indicating that the emission of methanol is not associated with a Keplerian disk or rotating-infalling cavity, and it is more likely associated with outflowing gas. We speculate that CH${}_3$OH traces a disk wind gas accelerated at the base. The launching region would be at a radius of a few astronomical units from the YSO.

arXiv commentAstronomy & Astrophysics Letter, in press

References in corpus (24)

• A 0.2 solar mass protostar with a Keplerian disk in the very young L1527 IRS system
• A Keplerian disk around a Class 0 source: ALMA observations of VLA1623A
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• Weeds: a CLASS extension for the analysis of millimeter and sub-millimeter spectral surveys
• Locating the Launching Region of T Tauri Winds: The Case of DG Tau
• A highly-collimated SiO jet in the HH212 protostellar outflow
• Rotation and Outflow motions in the very low-mass Class 0 protostellar system HH 211 at subarcsecond resolution
• First results from the CALYPSO IRAM-PdBI survey. II. Resolving the hot corino in the Class 0 protostar NGC 1333-IRAS2A
• The ALMA view of the protostellar system HH212 - The wind, the cavity, and the disk
• Predicted rotation signatures in MHD disc winds and comparison to DG Tau observations
• PdBI sub-arcsecond study of the SiO microjet in HH212 - Origin and collimation of Class 0 jets
• ALMA Results of the Pseudodisk, Rotating disk, and Jet in Continuum and HCO+ in the Protostellar System HH 212
• HH 212: SMA Observations of a Remarkable Protostellar Jet
• The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO2 emission
• Infall and Outflow around the HH 212 protostellar system
• Jet Motion, Internal Working Surfaces, and Nested Shells in the Protostellar System HH 212
• Water and acetaldehyde in HH212: The first hot corino in Orion
• Multi-line (sub)millimetre observations of the high-mass proto cluster IRAS 05358+3543
• The effect of magnetic fields on the formation of circumstellar discs around young stars
• Physical structure and water line spectrum predictions of the Intermediate Mass protostar OMC2-FIR4
• High SiO abundance in the HH212 protostellar jet
• First results from the CALYPSO IRAM-PdBI survey. I. Kinematics of the inner envelope of NGC1333-IRAS2A
• Velocity and magnetic fields within 1000 AU from a massive YSO
• Molecule survival in magnetized protostellar disk winds. II. Predicted H2O line profiles versus Herschel/HIFI observations

Cited by in corpus (14)

• Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• ATLASGAL-selected massive clumps in the inner Galaxy: V. Temperature structure and evolution
• First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
• Discovery of a sub-Keplerian disk with jet around a 20Msun young star. ALMA observations of G023.01-00.41
• A 100 au-Wide Bipolar Rotating Shell Emanating From The HH 212Protostellar Disk: A Disk Wind?
• The search for high-mass protostars with ALMA revealed up to kilo-parsec scales (SPARKS): I. Indication for a centrifugal barrier in the environment of a single high-mass envelope
• First Hot Corino detected around an Isolated Intermediate-Mass Protostar: Cep\,E-mm
• Deuterated methanol on Solar System scale around the HH212 protostar
• Water and interstellar complex organics associated with the HH 212 protostellar disc - On disc atmospheres, disc winds, and accretion shocks
• The HH 212 interstellar laboratory: astrochemistry as a tool to reveal protostellar disks on Solar System scales around a rising Sun
• Deuterated Formaldehyde in the low mass protostar HH212
• The Giant Herbig-Haro Flow HH 212 and Associated Star Formation
• Physicochemical models: source-tailored or generic?