2011A&A...532A..85K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST08:03:22

2011A&A...532A..85K - Astronomy and Astrophysics, volume 532A, 85-85 (2011/8-1)

Continuum and line modelling of discs around young stars. II. Line diagnostics for GASPS from the DENT grid.

KAMP I., WOITKE P., PINTE C., TILLING I., THI W.-F., MENARD F., DUCHENE G. and AUGEREAU J.-C.

Abstract (from CDS):

We want to understand the chemistry and physics of discs on the basis of a large unbiased and statistically relevant grid of disc models. One of the main goals is to explore the diagnostic power of various gas emission lines and line ratios for deriving main disc parameters such as the gas mass. We explored the results of the DENT grid (Disk Evolution with Neat Theory) that consists of 300000 disc models with 11 free parameters. Through a statistical analysis, we searched for correlations and trends in an effort to find tools for disc diagnostic. All calculated quantities like species masses, temperatures, continuum, and line fluxes differ by several orders of magnitude across the entire parameter space. The broad distribution of these quantities as a function of input parameters shows the limitation of using a prototype T Tauri or Herbig Ae/Be disc model. The statistical analysis of the DENT grid shows that CO gas is rarely the dominant carbon reservoir in discs. Models with large inner radii (10 times the dust condensation radius) and/or shallow surface density gradients lack massive gas-phase water reservoirs. Also, 60% of the discs have gas temperatures averaged over the oxygen mass in the range between 15 and 70K; the average gas temperatures for CO and O differ by less than a factor two. Our study of the observational diagnostics shows that the [CII]158µm fine structure line flux is very sensitive to the stellar UV flux and presence of a UV excess, and that it traces the outer disc radius (Rout). In the submm, the CO low J rotational lines also trace Rout. Low [OI]63/145 line ratios (<a few) can be explained with cool atomic O gas in the uppermost surface layers leading to self-absorption in the 63µm line. This occurs mostly for massive non-flaring, settled disc models without UV excess. A combination of the [OI]63 line and low J CO lines correlates with several disc properties, such as the average OI gas temperature in discs, the outer disc radius, and the UV excess. The [OI]63/CO 2-1 line ratio is a powerful diagnostic for breaking disc modelling degeneracies. A combination of the [OI]63µm flux and the [OI]63/CO 2-1 line ratio can be used for Mgas≤10–3M to obtain an order of magnitude estimate for the disc gas mass purely from gas observations. The previously used conversion of a CO submm line flux alone generally leads to larger uncertainties.

Abstract Copyright:

Journal keyword(s): astrochemistry - circumstellar matter - stars: formation - radiative transfer - methods: numerical - line: formation

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 - 2020
#notes
1 V* ET Cha Or* 08 43 18.5820197784 -79 05 18.203801931     13.97     M2 68 0

    Equat.    Gal    SGal    Ecl

C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST08:03:22

Available data : Basic data  •  Identifiers  •  Plot & images  •  Bibliography  •  Measurements  •  External archives  •  Notes  •  Annotations


Basic data :
V* ET Cha -- Variable Star of Orion Type
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:
IR (2MASS,IRAS,...), X (Ref,RECX,...), V* (ASAS,V*), *iC (ECHA), Or* (Ref)
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) :
08 43 18.5820197784 -79 05 18.203801931 (Optical) [ 0.2454 0.3276 90 ] A 2018yCat.1345....0G
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) :
08 45 04.5802785471 -78 54 21.185652330 [ 0.2454 0.3276 90 ]
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) :
292.5702904507809 -21.6373898622726 [ 0.2454 0.3276 90 ]
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 :
-27.343 27.323 [0.487 0.571 90] A 2018yCat.1345....0G
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):
10.9084 [0.3123] A 2018yCat.1345....0G
Spectral type is made of 3 parts: %coding is composed of 4 parts :
  • the spectral type, which is made of a temperature class, eventually a luminosity class (roman number) and/or spectral peculiarities;
  • a quality letter: A=best quality→E=worst quality, {� } =unknown quality %
  • a quality letter: A=best quality -> E=worst quality, {� } =unknown quality
  • bibcode : bibcode of the spectral type reference
Spectral type:
M2 E ~
Syntax of fluxes (or magnitudes) is : "filter-name (System) flux-value [error] quality MultVarFlags bibcode"
  • filter-name : U, B, V, R, I, G, J, H, K, u, g, r, i, z
  • (System) : may be AB (default is Vega)
  • flux-value : value of flux or magnitude
  • [error] : error value
  • quality : flag of quality of the flux value ( A=best quality -> E=worst quality, {� } =unknown quality)
  • MultVarFlags : Mult is zero or one char (J) for joined photometry ; Var can be zero or two chars (V[0-4])
  • bibcode : bibcode of the flux reference
Fluxes (5) :
V 13.97 [~] D 2006IBVS.5721....1K
G 13.3292 [0.0029] C 2018yCat.1345....0G
J 10.505 [0.026] D 2006ApJ...652.1572B
H 9.834 [0.021] D 2006ApJ...652.1572B
K 9.431 [0.023] D 2006ApJ...652.1572B
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Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

: 1 : 21 Display criteria :

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (13) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

2MASS J08431857-7905181 IRAS F08450-7854 USNO-A2.0 0075-01725894 Gaia DR2 5209024366240981632
ASAS J084319-7905.4 IRAS 08450-7854 V* ET Cha
ECHA J0843.3-7905 RECX 15 WISE J084318.52-790518.0
ECHA J0843.3-7915 UCAC3 22-14197 [LAL2010] 9

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References (68 between 1850 and 2020) (Total 68)
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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Collections of Measurements


distance : 1    PM : 2    PLX : 1    V* : 1   

   

Observing logs


herschel : 9   

   


External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Data at NED - NASA/IPAC Extragalactic Database : V* ET Cha

Link by name to the catalogue in VizieR :

2MASS J08431857-7905181 IRAS F08450-7854 IRAS 08450-7854 UCAC3 22-14197 USNO-A2.0 0075-01725894
V* ET Cha WISE J084318.52-790518.0 Gaia DR2 5209024366240981632

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2020.07.13-08:03:22

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