J/A+A/651/A48 Compact disks CO isotopologues line fluxes (Miotello+, 2021)
Compact Disks. An explanation to faint CO emission in Lupus disks.
Miotello A., Rosotti G., Ansdell M., Facchini S., Manara C., Williams J.P.,
Bruderer S.
<Astron. Astrophys. 651, A48 (2021)>
=2021A&A...651A..48M 2021A&A...651A..48M (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Stars, pre-main sequence
Keywords: protoplanetary disks - radiative transfer
Abstract:
ALMA disk surveys have shown that a large fraction of observed
protoplanetary disks in nearby Star-Forming Regions (SFRs) are fainter
than expected in CO isotopologue emission. Disks not detected in 13CO
line emission are also faint and often unresolved in the continuum
emission at an angular resolution of around 0.2 arcseconds.
Focusing on the Lupus SFR, the aim of this work is to investigate
whether this population comprises radially extended and low mass disks
- as commonly assumed so far - or if it is of intrinsically radially
compact disks, an interpretation that we propose in this paper. The
latter scenario was already proposed for individual sources or small
samples of disks, while this work targets a large population of disks
in a single young SFR for which statistical arguments can be made.
A new grid of physical-chemical models of compact disks has been run
with the physical-chemical code DALI in order to cover a region of the
parameter space that had not been explored before with this code. Such
models have been compared with 12CO and 13CO ALMA observations of
faint disks in the Lupus SFR. The simulated integrated continuum and
CO isotopologue fluxes of the new grid of compact models are reported.
Lupus disks that are not detected in 13CO emission and with faint or
undetected 12CO emission are consistent with compact disk models. For
disks with a limited radial extent, the emission of CO isotopologues
is mostly optically thick and it scales with the surface area: i.e.,
it is fainter for smaller objects. The fraction of compact disks is
potentially between roughly 50% and 60% of the entire Lupus sample.
Deeper observations of 12CO and 13CO at a moderate angular
resolution will allow us to distinguish whether faint disks are
intrinsically compact, or if they are extended but faint, without the
need of resolving them. If the fainter end of the disk population
observed by ALMA disk surveys is consistent with such objects being
very compact, this will either create a tension with viscous spreading
or require MHD winds or external processes to truncate the disks.
Description:
In this work DALI models of compact disks (Rc = 0.5, 1, 2, 5, 15 au)
have been run and CO isotopologues emission was simulated.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb2.dat 110 180 Parameters of the T Tauri models and simulated
fluxes integrated assuming a distance d=150pc
and a beam size of 10"
tableb3.dat 110 180 Parameters of the VLMSs models and simulated
fluxes integrated assuming a distance d=150pc
and a beam size of 10"
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Byte-by-byte Description of file: tableb2.dat tableb3.dat
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Bytes Format Units Label Explanations
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1- 4 F4.1 au Rc Critical radius
6- 8 F3.1 --- gamma Power-law index of the surface density
10- 14 E5.2 Msun Mdisk Total disk mass
16- 19 F4.1 deg i Inclination
21- 32 E12.3 Jy cont1.3mm Continuum flux density @1.3 mm
34- 45 E12.3 K.km/s F12CO(2-1) 12CO (2-1) line flux (1)
47- 58 E12.3 K.km/s F13CO(2-1) 13CO (2-1) line flux (1)
60- 71 E12.3 K.km/s FC18O(2-1) C18O (2-1) line flux (1)
73- 84 E12.3 K.km/s F12CO(3-2) 12CO (3-2) line flux (1)
86- 97 E12.3 K.km/s F13CO(3-2) 13CO (3-2) line flux (1)
99-110 E12.3 K.km/s FC18O(3-2) C18O (3-2) line flux (1)
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Note (1): Line fluxes are continuum subtracted.
The conversion between Kelvin and Jy is reported in Appendix B of
Bruderer et al. (2013A&A...559A..46B 2013A&A...559A..46B).
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Acknowledgements:
Anna Miotello, amiotell(at)eso.org
(End) Patricia Vannier [CDS] 19-May-2021