1999A&A...342..257K


Query : 1999A&A...342..257K

1999A&A...342..257K - Astronomy and Astrophysics, volume 342, 257-270 (1999/2-1)

Depletion of CO in a cold dense cloud core of IC 5146.

KRAMER C., ALVES J., LADA C.J., LADA E.A., SIEVERS A., UNGERECHTS H. and WALMSLEY C.M.

Abstract (from CDS):

We have used the IRAM 30m telescope to map the C18O(1->0) and (2->1) transitions in a region of 0.5x0.5pc2 (200''x200'') in the nearby (460pc distance) molecular cloud IC5146 at resolutions of down to 0.025pc. Additionally, we have observed the corresponding C17O transitions towards 24 positions in the central region of the cloud as a check on optical depth effects. On the basis of these observations, we conclude that the C18O emission observed by us is optically thin and that the observed C18O(2->1)/(1->0) ratio is consistent with gas at 10 K and density in the range 104 to 105 cm–3. We have estimated C18O column densities over the region mapped, using an LVG program to correct for excitation effects, and have compared them, at the same spatial resolution of 30'', with the dust extinction derived from the NIR images of Lada et al. (1998ApJ...495..871L) From this, we find a roughly constant, though with considerable dispersion, ratio of C18O column density to visual extinction (AV) in directions with AV less than ∼10 magnitudes. The ratio is compatible with previous determinations of the [C18O]/[H2] abundance ratio, e.g. 1.7*10–7 as obtained by Frerking et al. (1982) At extinctions higher than ∼10 magnitudes, however, there is a systematic fall-off in the ratio N(C18O)/AV which we attribute to depletion of C18O onto dust ice mantles within the dense, n>104cm–3, and cold, Tdust≲15K, Tgas∼10K, core interior. This fall-off is also seen, though with less statistical significance, in our observed dependence of N(C17O)/AV with AV. We thus think it unlikely that optical depth effects are influencing our conclusions. We have additionally made pointed C18O(1->0) and (2->1) observations towards 94 background stars with extinction greater than 10 magnitudes from the study of Lada et al. (1994ApJ...429..694L) These in general confirm our mapping results.

Abstract Copyright:

Journal keyword(s): ISM: molecules - ISM: kinematics and dynamics - ISM: individual objects: IC 5146 - ISM: dust, extinction - ISM: clouds - ISM: abundances

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 IC 5146 OpC 21 53 29 +47 14.8           ~ 425 2

Query : 1999A&A...342..257K

Basic data :
IC 5146 -- Open (galactic) Cluster
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
OpC (2013A&A,OCISM,...), Cl* (2020A&A,C,...), As* (2019AJ,[KC2019]), HII (LBN), ISM (Min), * (IC)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
21 53 29.3 +47 14 46 (Optical) [ ] D 2020A&A...633A..99C
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
FK4 coord. (ep=B1950 eq=1950) :
21 51 33.5 +47 00 35 [ ]
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
Gal coord. (ep=J2000) :
094.3820 -05.5204 [ ]
Syntax of proper motions is : "pm-ra pm-dec [error ellipse] quality bibcode"
  • pm-ra : mu-ra*cos(dec) (expressed in the ICRS system in mas/yr)
  • pm-dec : mu-dec (expressed in the ICRS system in mas/yr)
  • [error ellipse] : error major axis and minor axis (in mas), orientation angle (in deg)
  • quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality)
  • bibcode : bibcode of the proper motion reference
Proper motions mas/yr :
-2.910 -2.490 [0.037 0.037 90] C 2020A&A...633A..99C
Syntax of radial velocity (or/and redshift) is : "value [error] (wavelength) quality bibcode"
  • value : radial velocity or/and redshift (Heliocentric frame) according to your Output Options
    (redshift may be not displayed if the data value is <0 and the database inside value is a radial velocity)
  • [error] : error of the corresponding value displayed before
  • (wavelength) : wavelength range of the measurement : Rad, mm, IR, Opt, UV, Xray, Gam or  '∼'(unknown)
  • quality : flag of quality ( A=best quality -> E=worst quality, {� } =unknown quality)
  • bibcode : bibcode of the value's origin
Radial velocity / Redshift / cz :
V(km/s) -5.48 [0.25] / z(spectroscopic) -0.000018 [0.000001] / cz -5.48 [0.25]
   (NIR) A 2019A&A...623A..80C
Syntax of parallax is : 'value quality [error] bibcode'
  • value : parallax value
  • quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality)
  • [error] : mean error
  • bibcode : bibcode of the parallax reference
Parallaxes (mas):
1.213 [0.013] C 2020A&A...633A..99C
Syntax of angular size is : "maj-axis min-axis angle (wtype) quality bibcode"
  • maj-axis : major axis size (arc minutes)
  • min-axis : minor axis size (arc minutes)
  • angle : orientation angle (in degrees)
  • (wtype) : wavelength class for the origin of the angular size (Rad, mm, IR, Opt, UV, Xray, Gam)
  • quality : flag of quality of the angular size values ( A=best quality -> E=worst quality, {� } =unknown quality)
  • bibcode : bibcode of the angular size reference
Angular size (arcmin):
8.2 8.2 0 (Opt) D 2020A&A...633A..99C
SIMBAD within arcmin
', {sourceSize:12, color:'#30a090'})); aladin.on('objectClicked', function(object) { var objName=object.data.MAIN_ID; aladin.showPopup(object.ra,object.dec,'',''+ objName+''); });" title="Show Simbad objects"> Overlay Simbad points in this preview
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The search radius has to be specified by the user. It is currently limited to a maximum of 30 arcsec. It depends mostly on the precision or quality of the coordinates (SIMBAD and VizieR catalogs), the resolution of the images from which the sources were extracted, source extent, and source crowding.
Suggestions are: crowded field: 0.5 to 1.5 arcsec, 3 arcsec otherwise; uncertain coordinates (SIMBAD quality E or coordinates without reference): 5 to 30 arsec (risky!).
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Some important notes on this object about identifications and objects associations.
notes:

  • cluster embedded in nebula


Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

The count displayed here is the number of children objects.
The list obtained by clicking the button may be larger, as some children may be linked with different references or probability.

%This number is the number of distinct objets linked, by using this button, you will obtain all links (may be more than one) from that object to his children

: 854
Display criteria :

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (12) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

IC 5146 LBN 424 NAME Cocoon Nebula OCl 213.0
C 2151+470 LBN 094.43-05.58 OCISM 43 [KC2019] Theia 88
Cl Collinder 470 Min 2-70 OCl 213 [KPS2012] MWSC 3571

References (425 between 1850 and 2022) (Total 425)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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                Reference summaries :

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Collections of Measurements


velocities : 3    distance : 3    Fe_H : 1    PLX : 5    PM : 5   

   

Observing logs


herschel : 4    ISO : 12   

   


External archives :

Data at NED - NASA/IPAC Extragalactic Database : IC 5146


Indications mainly about references on other documents
Notes (1) :


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2022.05.21-08:17:50

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