2015A&A...579A.114M


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.08CEST03:57:51

2015A&A...579A.114M - Astronomy and Astrophysics, volume 579A, 114-114 (2015/7-1)

A low-mass protostar's disk-envelope interface: disk-shadowing evidence from ALMA DCO+ observations of VLA 1623.

MURILLO N.M., BRUDERER S., VAN DISHOECK E.F., WALSH C., HARSONO D., LAI S.-P. and FUCHS C.M.

Abstract (from CDS):

Historically, due to instrumental limitations and a lack of disk detections, the structure of the transition from the envelope to the rotationally supported disk has been poorly studied. This is now possible with ALMA through observations of CO isotopologues and tracers of freezeout. Class 0 sources are ideal for such studies given their almost intact envelope and young disk. The structure of the disk-envelope interface of the prototypical Class 0 source, VLA1623A, which has a confirmed Keplerian disk, is constrained through modeling and analysis of ALMA observations of DCO+ (3-2) and C18O (2-1) rotational lines. The physical structure of VLA1623 is obtained from the large-scale spectral energy distribution (SED) and continuum radiative transfer. An analytic model using a simple network coupled with radial density and temperature profiles is used as input for a 2D line radiative transfer calculation for comparison with the ALMA Cycle 0 12-m array and Cycle 2 ACA observations of VLA1623. The DCO+ emission shows a clumpy structure bordering VLA1623A's Keplerian disk. This suggests a cold ring-like structure at the disk-envelope interface. The radial position of the observed DCO+ peak is reproduced in our model only if the region's temperature is between 11K and 16K, lower than expected from models constrained by continuum data and source SED. Altering the density profile has little effect on the DCO+ peak position, but increased density is needed to reproduce the observed C18O tracing the disk. The observed DCO+ (3-2) emission around VLA1623A is the product of shadowing of the envelope by the disk observed in C18O. Disk-shadowing causes a drop in the gas temperature outside of the disk on >200AU scales, encouraging the production of deuterated molecules. This indicates that the physical structure of the disk-envelope interface differs from the rest of the envelope, highlighting the drastic impact that the disk has on the envelope and temperature structure. The results presented here show that DCO+ is an excellent cold temperature tracer.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: low-mass - stars: protostars - ISM: individual objects: VLA1623 - methods: observational - techniques: interferometric

Simbad objects: 8

goto Full paper

goto View the reference in ADS

Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 3C 279 QSO 12 56 11.1664521013 -05 47 21.531840471   18.01 17.75 15.87   ~ 2702 2
2 QSO B1514-24 BLL 15 17 41.8135246339 -24 22 19.482167214   15.13 14.00 13.95   ~ 643 3
3 QSO B1622-253 QSO 16 25 46.89164010 -25 27 38.3267989   21.3 20.6 19.60   ~ 301 1
4 CRBR 2316.0-1626 Y*? 16 26 17.46816 -24 23 12.9552           ~ 21 0
5 ALMA J162625.63-242429.5 Y*O 16 26 25.62 -24 24 28.9           ~ 28 1
6 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 373 0
7 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3027 0
8 QSO B1730-130 QSO 17 33 02.70578476 -13 04 49.5481484   18 18.5 18.78 17.39 ~ 983 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2015A&A...579A.114M and select 'bookmark this link' or equivalent in the popup menu


2020.07.08-03:57:51

© Université de Strasbourg/CNRS

    • Contact