2013A&A...555A.140S


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.09CET22:00:25

2013A&A...555A.140S - Astronomy and Astrophysics, volume 555A, 140-140 (2013/7-1)

Determination of the far-infrared dust opacity in a prestellar core.

SUUTARINEN A., HAIKALA L.K., HARJU J., JUVELA M., ANDRE P., KIRK J.M., KOENYVES V. and WHITE G.J.

Abstract (from CDS):

Mass estimates of interstellar clouds from far-infrared and submillimetre mappings depend on the assumed dust absorption cross-section for radiation at those wavelengths. The aim is to determine the far-IR dust absorption cross-section in a starless, dense core located in Corona Australis. The value is needed for determining of the core mass and other physical properties. It can also have a bearing on the evolutionary stage of the core. We correlated near-infrared stellar H-Ks colour excesses of background stars from NTT/SOFI with the far-IR optical depth map, τFIR, derived from Herschel 160, 250, 350, and 500µm data. The Herschel maps were also used to construct a model for the cloud to examine the effect of temperature gradients on the estimated optical depths and dust absorption cross-sections. A linear correlation is seen between the colour H-Ks and τFIR up to high extinctions (AV∼25). The correlation translates to the average extinction ratio A250µm/AJ=0.0014±0.0002, assuming a standard near-infrared extinction law and a dust emissivity index β=2. Using an empirical NH/AJ ratio we obtain an average absorption cross-section per H nucleus of τH250µm=(1.8±0.3)x10–25cm H-atom, corresponding to a cross-section per unit mass of gas K250(µmg=0.08±0.01cm.g. The cloud model, however, suggests that owing to the bias caused by temperature changes along the line-of-sight, these values underestimate the true cross-sections by up to 40% near the centre of the core. Assuming that the model describes the effect of the temperature variation on τFIR correctly, we find that the relationship between H-Ks and τFIR agrees with the recently determined relationship between τH and NH in Orion A. The derived far-IR cross-section agrees with previous determinations in molecular clouds with moderate column densities, and is not particularly large compared with some other cold cores. We suggest that this is connected to the core not being very dense (the central density is likely to be ∼105cm), and judging from previous molecular line data, it appears to be at an early stage of chemical evolution. Based partly on observations collected at the European Southern Observatory, Chile (ESO programmes 075.C-0748 and 077.C-0562).

Abstract Copyright:

Journal keyword(s): ISM: clouds, dust, extinction

Simbad objects: 12

goto Full paper

goto View the reference in ADS

Number of rows : 12

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 LDN 1521 DNe 04 33.1 +26 06           ~ 49 0
2 LDN 1642 MoC 04 35 18 -14 13.9           ~ 135 0
3 NAME Taurus Dark Cloud SFR 04 41.0 +25 52           ~ 3335 0
4 NAME Ori A MoC 05 38 -07.1           ~ 2619 0
5 NAME Musca Cld 12 23 -71.3           ~ 152 0
6 NAME Thumbprint Nebula DNe 12 44 55.6 -78 48 16           ~ 22 0
7 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 2944 0
8 LDN 57 DNe 17 22 38.2 -23 49 34           ~ 276 1
9 NAME CrA C cor 19 03 56.1 -37 15 32           ~ 12 0
10 LDN 663 DNe 19 36 55 +07 34.4           ~ 539 0
11 IC 5146 SFR 21 53 24 +47 16.0   7.82 7.2     ~ 376 2
12 NAME Vela Field reg ~ ~           ~ 143 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2013A&A...555A.140S and select 'bookmark this link' or equivalent in the popup menu


2019.12.09-22:00:25

© Université de Strasbourg/CNRS

    • Contact