FAUST VI. VLA 1623--2417 B: a new laboratory for astrochemistry around protostars on 50 au scale

Abstract

The ALMA interferometer, with its unprecedented combination of high-sensitivity and high-angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar System scales. Astrochemistry has benefited from imaging interstellar complex organic molecules in these jet-disk systems. Here we report the first detection of methanol (CH3OH) and methyl formate (HCOOCH3) emission towards the triple protostellar system VLA1623-2417 A1+A2+B, obtained in the context of the ALMA Large Program FAUST. Compact methanol emission is detected in lines from Eu = 45 K up to 61 K and 537 K towards components A1 and B, respectively. LVG analysis of the CH3OH lines towards VLA1623-2417 B indicates a size of 0.11-0.34 arcsec (14-45 au), a column density N(CH3OH) = 10^16-10^17 cm-2, kinetic temperature > 170 K, and volume density > 10^8 cm-3. An LTE approach is used for VLA1623-2417 A1, given the limited Eu range, and yields Trot < 135 K. The methanol emission around both VLA1623-2417 A1 and B shows velocity gradients along the main axis of each disk. Although the axial geometry of the two disks is similar, the observed velocity gradients are reversed. The CH3OH spectra from B shows two broad (4-5 km s-1) peaks, which are red- and blue-shifted by about 6-7 km s-1 from the systemic velocity. Assuming a chemically enriched ring within the accretion disk, close to the centrifugal barrier, its radius is calculated to be 33 au. The methanol spectra towards A1 are somewhat narrower (about 4 km s-1), implying a radius of 12-24 au.

arXiv commentMNRAS, in press

References in corpus (37)

• BANYAN. XI. The BANYAN $\Sigma$ multivariate Bayesian algorithm to identify members of young associations within 150 pc
• Our astrochemical heritage
• Unveiling the Circumstellar Envelope and Disk: A Sub-Arcsecond Survey of Circumstellar Structures
• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• A Keplerian disk around a Class 0 source: ALMA observations of VLA1623A
• The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293-2422B
• 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
• ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet
• Weeds: a CLASS extension for the analysis of millimeter and sub-millimeter spectral surveys
• The ALMA-PILS survey: Inventory of complex organic molecules towards IRAS 16293-2422 A
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA
• Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey
• The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars
• Jets and Outflows From Star to Cloud: Observations Confront Theory
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• Complex organics in IRAS 4A revisited with ALMA and PdBI: Striking contrast between two neighbouring protostellar cores
• Theoretical HDO emission from low-mass protostellar envelopes
• Disentangling the entangled: Observations and analysis of the triple non-coeval protostellar system VLA1623
• Hot Corinos Chemical Diversity: Myth or Reality?
• First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
• Vertical Structure of the Transition Zone from Infalling Rotating Envelope to Disk in the Class 0 Protostar, IRAS04368+2557
• Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud
• ALMA Observations of Polarized 872 $\mu$m Dust Emission from the Protostellar Systems VLA 1623 and L1527
• Glycolaldehyde in Perseus young solar analogs
• FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5
• Tracing the cold and warm physico-chemical structure of deeply embedded protostars: IRAS 16293-2422 versus VLA 1623-2417
• FAUST III. Misaligned rotations of the envelope, outflow, and disks in the multiple protostellar system of VLA 1623$-$2417
• Misaligned Twin Molecular Outflows From Class-0 Proto-stellar Binary System VLA 1623A Unveiled by ALMA
• Water and interstellar complex organics associated with the HH 212 protostellar disc - On disc atmospheres, disc winds, and accretion shocks
• Disentangling the jet emission from protostellar systems. The ALMA view of VLA1623
• Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623A
• On the origin of C${}_4$H and CH${}_3$OH in protostellar envelopes
• The immediate environment of the Class 0 protostar VLA1623, on scales of ~50-100 AU, observed at millimetre and centimetre wavelengths
• Revised SED of the triple protostellar system VLA 1623-2417
• Kinematics of Protostellar Objects in the $\rho$ Ophiuchus A Region

Cited by in corpus (5)

• CoCCoA: Complex Chemistry in hot Cores with ALMA. Selected oxygen-bearing species
• FAUST VIII. The protostellar disk of VLA 1623-2417 W and its streamers imaged by ALMA
• FAUST VII. Detection of A Hot Corino in the Prototypical Warm Carbon-Chain Chemistry Source IRAS 15398-3359
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Correlations among complex organic molecules around protostars: Effects of physical structure