CH${}_3$CN deuteration in the SVS13-A Class I hot-corino. SOLIS XV

Abstract

We studied the line emission from CH3CN and its deuterated isotopologue CH${}_2$DCN towards the prototypical Class I object SVS13-A, where the deuteration of a large number of species has already been reported. Our goal is to measure the CH${}_3$CN deuteration in a Class I protostar, for the first time, in order to constrain the CH${}_3$CN formation pathways and the chemical evolution from the early prestellar core and Class 0 to the evolved Class I stages. We imaged CH2DCN towards SVS13-A using the IRAM NOEMA interferometer at 3mm in the context of the Large Program SOLIS (with a spatial resolution of 1.8"x1.2"). The NOEMA images have been complemented by the CH${}_3$CN and CH${}_2$DCN spectra collected by the IRAM-30m Large Program ASAI, that provided an unbiased spectral survey at 3mm, 2mm, and 1.3mm. The observed line emission has been analysed using LTE and non-LTE LVG approaches. The NOEMA/SOLIS images of CH2DCN show that this species emits in an unresolved area centered towards the SVS13-A continuum emission peak, suggesting that methyl cyanide and its isotopologues are associated with the hot corino of SVS13-A, previously imaged via other iCOMs. In addition, we detected 41 and 11 ASAI transitions of CH${}_3$CN and CH2DCN, respectively, which cover upper level energies (Eup) from 13 to 442 K and from 18 K to 200 K, respectively. The derived [CH2DCN]/[CH3CN] ratio is $\sim$9\%. This value is consistent with those measured towards prestellar cores and a factor 2-3 higher than those measured in Class 0 protostars. Contrarily to what expected for other molecular species, the CH3CN deuteration does not show a decrease in SVS13-A with respect to measurements in younger prestellar cores and Class 0 protostars. Finally, we discuss why our new results suggest that CH3CN was likely synthesised via gas-phase reactions and frozen onto the dust grain mantles during the cold prestellar phase.

20 pages, 2 tables, 12 figures

References in corpus (25)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• Constraining the abundances of complex organics in the inner regions of solar-type protostars
• Four annular structures in a protostellar disk less than 500,000 years old
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars
• Reactivity of HCO with CH3 and NH2 on Water Ice Surfaces. A Comprehensive Accurate Quantum Chemistry Study
• O-bearing complex organic molecules at the cyanopolyyne peak of TMC-1: detection of C2H3CHO, C2H3OH, HCOOCH3, and CH3OCH3
• Complex organic molecules in low-mass protostars on Solar System scales -- II. Nitrogen-bearing species
• Chemical desorption versus energy dissipation: insights from ab-initio molecular dynamics of HCO formation
• H2 formation on interstellar grains and the fate of reaction energy
• Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud
• Water delivery from cores to disks: deuteration as a probe of the prestellar inheritance of H2O
• Glycolaldehyde in Perseus young solar analogs
• Decrease of the organic deuteration during the evolution of Sun-like protostars: the case of SVS13-A
• The role of C/O in nitrile astrochemistry in PDRs and planet-forming disks
• ALMA observations of doubly deuterated water: Inheritance of water from the prestellar environment
• Space and laboratory observation of the deuterated cyanomethyl radical HDCCN
• Complex organic molecules during low-mass star formation: Pilot survey results
• CALYPSO view of SVS 13A with PdBI: Multiple jet sources
• First measurement of the 14N/15N ratio in the analogue of the Sun progenitor OMC-2 FIR4
• The Physical Properties of the SVS 13 Protobinary System: Two Circumstellar Disks and a Spiraling Circumbinary Disk in the Making
• Hot corino chemistry in the Class I binary source Ser-emb 11
• Hot and dense water in the inner 25 AU of SVS13-A
• A 3mm chemical exploration of small organics in Class I YSOs

Cited by in corpus (10)

• PRODIGE -- Envelope to Disk with NOEMA II. Small-scale temperature structure and a streamer feeding the SVS13A protobinary using CH3CN and DCN
• Streamers feeding the SVS13-A protobinary system: astrochemistry reveals accretion shocks?
• PRODIGE -- Envelope to Disk with NOEMA III. The origin of complex organic molecule emission in SVS13A
• Peptide Bonds in the Interstellar Medium: Facile Autocatalytic Formation from Nitriles on Water-Ice Grains
• Destruction of interstellar methyl cyanide (CH3CN) via collisions with He+ ions
• Interstellar Chemistry of CN Radicals on Ices: The formation of CH3CN and CH3NC and potential connection to acetamide
• Resolved Gas Temperatures and 12C/13C ratios in SVS13A from ALMA Observations of CH3CN and CH3-13-CN
• PRODIGE VI -- Envelope to Disk with NOEMA: VI. The Missing Sulfur Problem
• The hot corino-like chemistry of four FUor-like protostars
• Digging into the Massive Protostar S255IR NIRS3: A Study of Nitrogen-Bearing Molecules and Their Prebiotic Chemistry