Molecular ions in the protostellar shock L1157-B1

Abstract

We perform a complete census of molecular ions with an abundance larger than 1e-10 in the protostellar shock L1157-B1 by means of an unbiased high-sensitivity survey obtained with the IRAM-30m and Herschel/HIFI. By means of an LVG radiative transfer code the gas physical conditions and fractional abundances of molecular ions are derived. The latter are compared with estimates of steady-state abundances in the cloud and their evolution in the shock calculated with the chemical model Astrochem. We detect emission from HCO+, H13CO+, N2H+, HCS+, and, for the first time in a shock, from HOCO+, and SO+. The bulk of the emission peaks at blueshifted velocity, ~ 0.5-3 km/s with respect to systemic, has a width of ~ 4-8 km/s, and is associated with the outflow cavities (T_kin ~ 20-70 K, n(H2) ~ 1e5 cm-3). Observed HCO+ and N2H+ abundances are in agreement with steady-state abundances in the cloud and with their evolution in the compressed and heated gas in the shock for cosmic rays ionization rate Z = 3e-16 s-1. HOCO+, SO+, and HCS+ observed abundances, instead, are 1-2 orders of magnitude larger than predicted in the cloud; on the other hand they are strongly enhanced on timescales shorter than the shock age (~2000 years) if CO2, S or H2S, and OCS are sputtered off the dust grains in the shock. The performed analysis indicates that HCO+ and N2H+ are a fossil record of pre-shock gas in the outflow cavity, while HOCO+, SO+, and HCS+ are effective shock tracers and can be used to infer the amount of CO2 and sulphur-bearing species released from dust mantles in the shock. The observed HCS+ (and CS) abundance indicates that OCS should be one of the main sulphur carrier on grain mantles. However, the OCS abundance required to fit the observations is 1-2 orders of magnitude larger than observed. Further studies are required to fully understand the chemistry of sulphur-bearing species.

12 pages, 5 figures, accepted by A&A

References in corpus (6)

• A Flattened Protostellar Envelope in Absorption around L1157
• Warm SiO gas in molecular bullets associated with protostellar outflows
• HH 212: SMA Observations of a Remarkable Protostellar Jet
• The clumpy structure of the chemically active L1157 outflow
• Sulphur chemistry and molecular shocks: the case of NGC1333-IRAS2
• The CHESS survey of the L1157-B1 bow-shock: high and low excitation water vapor

Cited by in corpus (63)

• Gas phase formation of the prebiotic molecule formamide: insights from new quantum computations
• Protostars: Forges of cosmic rays?
• Seeds of Life in Space (SOLIS) III. Formamide in protostellar shocks: evidence for gas-phase formation
• Astrochemical evolution along star formation: Overview of the IRAM Large Program ASAI
• L1157-B1, a factory of complex organic molecules in a Solar-type star forming region
• Molecules with a peptide link in protostellar shocks: a comprehensive study of L1157
• ALMA and ROSINA detections of phosphorus-bearing molecules: the interstellar thread between star-forming regions and comets
• Cosmic-ray acceleration in young protostars
• The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO2 emission
• Ionization fraction and the enhanced sulfur chemistry in Barnard 1
• Silicon-bearing molecules in the shock L1157-B1: first detection of SiS around a Sun-like protostar
• The chemistry of phosphorus-bearing molecules under energetic phenomena
• Exploration of Cosmic Ray Acceleration in Protostellar Accretion Shocks and A Model for Ionization Rates in Embedded Protoclusters
• A 100 au-Wide Bipolar Rotating Shell Emanating From The HH 212Protostellar Disk: A Disk Wind?
• Astrochemistry at work in the L1157-B1 shock: acetaldehyde formation
• H2S in the L1157-B1 Bow shock
• Seeds of Life in Space (SOLIS) V. Methanol and acetaldehyde in the protostellar jet-driven shocks L1157-B0 and B1
• Probing the CO and methanol snow lines in young protostars. Results from the CALYPSO IRAM-PdBI survey
• Seeds of Life in Space (SOLIS). X. Interstellar Complex Organic Molecules in the NGC 1333 IRAS 4A outflows
• Gas and dust temperature in pre-stellar cores revisited: New limits on cosmic-ray ionization rate
• Seeds of Life in Space (SOLIS). VI. Chemical evolution of sulfuretted species along the outflows driven by the low-mass protostellar binary NGC1333-IRAS4A
• The density structure of the L1157 molecular outflow
• Ionization: a possible explanation for the difference of mean disk sizes in star-forming regions
• Evidence for a chemically differentiated outflow in Mrk 231
• Sulfur Chemistry in L1157-B1
• Chemical survey of Class I protostars with the IRAM-30m
• A young bipolar outflow from IRAS 15398-3359
• Impacts of pure shocks in the BHR71 bipolar outflow
• CSO and CARMA Observations of L1157. II. Chemical Complexity in the Shocked Outflow
• Sulphur-rich cold gas around the hot core precursor G328.2551-0.5321. An APEX unbiased spectral survey of the 2 mm, 1.2 mm, and 0.8 mm atmospheric windows
• Spectral Line Survey toward Young Massive Protostar NGC 2264 CMM3 in the 4 mm, 3 mm, and 0.8 mm Bands
• Abundance of HOCO+ and CO2 in the outer layers of the L1544 prestellar core
• A search for Cyanopolyynes in L1157-B1
• Particle acceleration and magnetic field amplification in massive young stellar object jets
• The SVS13-A Class I chemical complexity as revealed by S-bearing species. SOLIS XIII
• Sulfur-bearing molecules in Orion KL
• Sensitive survey for 13CO, CN, H2CO, and SO in the disks of T Tauri and Herbig Ae stars II: Stars in $\rho$ Oph and upper Scorpius
• Protonated CO2 in massive star-forming clumps
• The onset of energetic particle irradiation in Class 0 protostars
• Seeds of Life in Space SOLIS. IX. Chemical segregation of $\mathrm{S}{\mathrm{O}}_2$ and SO toward the low-mass protostellar shocked region of L1157
• Transport of Protostellar Cosmic Rays in Turbulent Dense Cores
• The L1157-B1 astrochemical laboratory: testing the origin of DCN
• Detection of HOCO+ in the protostar IRAS 16293-2422
• HCN/HNC chemistry in shocks: a study of L1157-B1 with ASAI
• Conformational isomerism of methyl formate: new detections of the higher-energy trans conformer and theoretical insights
• The double signature of local cosmic-ray acceleration in star-forming regions
• 3D modelling of HCO${}^{+}$ and its isotopologues in the low-mass proto-star IRAS16293$-$2422
• A new analytic approach to infer the cosmic-ray ionization rate in hot molecular cores from HCO${}^{+}$, N${}_2$H${}^{+}$, and CO observations
• Cosmic-ray-induced H${}_2$ line emission: Astrochemical modeling and implications for JWST observations
• A detailed temperature map of the archetypal protostellar shocks in L1157
• Evolution of Chemistry in the envelope of Hot Corinos (ECHOS). I. Extremely young sulphur chemistry in the isolated Class 0 object B335
• The physical and chemical structure of Sagittarius B2, VIII. Full molecular line survey of hot cores
• C-type shock modelling -- the effect of new H${}_2$-H collisional rate coefficients
• An ALCHEMI inspection of sulphur-bearing species towards the central molecular zone of NGC 253
• Chemical exploration of Galactic cold cores
• Physicochemical models: source-tailored or generic?
• The GUAPOS project. VI: the chemical inventory of shocked gas
• Erosion of a dense molecular core by a strong outflow from a massive protostar
• Collisional Pumping of OH Masers near Supernova Remnants
• Molecules with ALMA at Planet-forming Scales (MAPS) XII: Inferring the C/O and S/H ratios in Protoplanetary Disks with Sulfur Molecules
• Shock-type inference of L1157 B2 using methanol desorption
• Carbon chain diversity in L1544 and IRAS 16293-2422: an astrochemical pathfinder study for the SKAO
• H${}_2$ mass-velocity relationship from 3D numerical simulations of jet-driven molecular outflows