J/A+A/648/A33 ALMA continuum images of TW Hya (Macias+, 2021)
Characterizing the dust content of disk substructures in TW Hya.
Macias E., Guerra-Alvarado O., Carrasco-Gonzalez C., Ribas A.,
Espaillat C.C., Huang J., Andrews S.M.
<Astron. Astrophys. 648, A33 (2021)>
=2021A&A...648A..33M 2021A&A...648A..33M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Protostars ; Interferometry ;
Millimetric/submm sources
Keywords: accretion, accretion disks - protoplanetary disks -
planets and satellites: formation - stars: pre-main sequence -
radio continuum: general - techniques: interferometric
Abstract:
A key piece of information to understand the origin and role of
protoplanetary disk substructures is their dust content. In particular,
disk substructures associated with gas pressure bumps can work as dust
traps, accumulating grains and reaching the necessary conditions to
trigger the streaming instability.
In order to shed some light on the origin and role that disk
substructures play in planet formation, we aim to characterize the
dust content of substructures in the disk of TW Hya.
We present Atacama Large Millimeter Array (ALMA) observations of TW
Hya at 3.1mm with ∼50 milliarcsecond resolution. These new data were
combined with archival high angular resolution ALMA observations at
0.87mm, 1.3mm, and 2.1mm. We analyze these multiwavelength data to
infer a disk radial profile of the dust surface density, maximum
particle size, and slope of the particle size distribution.
Most previously known annular substructures in the disk of TW Hya are
resolved at the four wavelengths. Inside the inner 3au cavity, the
2.1mm and 3.1mm images show a compact source of free-free emission,
likely associated with an ionized jet. Our multiwavelength analysis of
the dust emission shows that the maximum particle size in the disk of
TW Hya is >1mm. The inner 20au are completely optically thick at all
four bands, which results in the data tracing different disk heights
at different wavelengths. Coupled with the effects of dust settling,
this prevents the derivation of accurate density and grain size
estimates in these regions. At r>20au, we find evidence of the
accumulation of large dust particles at the position of the bright
rings, indicating that these are working as dust traps. The total dust
mass in the disk is between 250 and 330M☉, which represents a
gas-to-dust mass ratio between 50 and 70. Our mass measurement is a
factor of 4.5-5.9 higher than the mass that one would estimate using
the typical assumptions of large demographic surveys.
Our results indicate that the ring substructures in TW Hya are ideal
locations to trigger the streaming instability and form new
generations of planetesimals.
Description:
We present images of the dust continuum emission at 0.87mm, 1.3mm,
2.1mm, and 3.1mm of the protoplanetary disk around TW Hya, obtained
with the Atacama Large Millimeter/submillimeter Array. Three images at
each wavelength are presented. One image is obtained using a Briggs
robust weighting that provides a good balance between sensitivity and
resolution (main panels in Figure 1 of the paper). Another image is
obtained with a Briggs robust weighting that produces a higher angular
resolution (insets in Figure 1 of the paper). The third image at each
wavelength (with suffix _circularbeam) has a circular beam with
FWHM=0.05" (images used in the analysis presented in the paper). All
images are presented as FITS files.
Objects:
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RA (2000) DE Designation(s)
-----------------------------------------------
11 01 51.91 -34 42 17.0 TW Hya = HIP 53911
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 150 12 List of fits images
fits/* . 12 Individual fits images
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See also:
J/A+A/592/A49 : TW Hya CO (2-1), CN (2-1) & CS (5-4) data cubes (Teague+, 2016)
J/A+A/592/A83 : HD 100546 and TW Hya model abundances (Kama+, 2016)
J/ApJ/862/L2 : First detection of HCOOH in TW Hya disk with ALMA (Favre+ 2018)
J/A+A/642/L15 : Near-infrared spectra for TW Hya (McLure+, 2020)
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 52 A23 "datime" Obs.date Observation date
54- 61 F8.4 GHz Freq Observed frequency
63- 67 I5 Kibyte size Size of FITS file
69- 99 A31 --- FileName Name of FITS file, in subdirectory fits
101-150 A50 --- Title Title of the FITS file
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Acknowledgements:
Enrique Macias, emaciasq(at)gmail.com
(End) Patricia Vannier [CDS] 01-Mar-2021