J/A+A/635/A12 GG Tau A ALMA 13CO and C18O(3-2) maps (Phuong+, 2020)
GG Tau A: gas properties and dynamics from the cavity to the outer disk.
Phuong N.T., Dutrey A., Diep P.N., Guilloteau S., Chapillon E., Di Folco E.,
Tang Y-W., Pietu V., Bary J., Beck T., Hersant F., Hoai D.T, Hure J.M.,
Nhung P.T., Pierens A., Tuan-Anh P.
<Astron. Astrophys. 635, A12 (2020)>
=2020A&A...635A..12P 2020A&A...635A..12P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Radio lines
Keywords: circumstellar matter - radio lines: stars - protoplanetary disks -
stars: individual: GG Tauri A
Abstract:
GG Tau A is the prototype of a young triple T Tauri star that is
surrounded by a massive and extended Keplerian outer disk.
The central cavity is not devoid of gas and dust and at least GG Tau
Aa exhibits its own disk of gas and dust emitting at millimeter
wavelengths. Its observed properties make this source an ideal
laboratory for investigating planet formation in young multiple
solartype stars.
We used new ALMA 13CO and C18O(3-2) observations obtained at high
angular resolution (∼0.2") together with previous CO(3-2) and
(6-5) ALMA data and continuum maps at 1.3 and 0.8mm in order to
determine the gas properties (temperature, density, and kinematics) in
the cavity and to a lesser extent in the outer disk.
By deprojecting, we studied the radial and azimuthal gas distribution
and its kinematics. We also applied a new method to improve the
deconvolution of the CO data and in particular better quantify the
emission from gas inside the cavity. We perform local nonlocal
thermodynamic equilibrium studies in order to determine the excitation
conditions and relevant physical parameters inside the ring and in the
central cavity.
Residual emission after removing a smooth-disk model indicates
unresolved structures at our angular resolution, probably in the form
of irregular rings or spirals. The outer disk is cold, with a
temperature <20K beyond 250au that drops quickly (∝r-1).
The kinematics of the gas inside the cavity reveals infall motions at
about 10% of the Keplerian speed. We derive the amount of gas in the
cavity, and find that the brightest clumps, which contain about 10% of
this mass, have kinetic temperatures 40-80K, CO column densities of a
few 1017cm-2, and H2 densities around 107cm-3.
Although the gas in the cavity is only a small fraction of the disk
mass, the mass accretion rate throughout the cavity is comparable to
or higher than the stellar accretion rate. It is accordingly
sufficient to sustain the circumstellar disks on a long timescale.
Description:
GG Tau A was observed with ALMA Band 9 during Cycle 0
(2011.0.00059.S) and Band 7 during Cycle 1 (2012.1.00129.S) and Cycle
3 (2015.1.00224.S). Anne Dutrey is the PI of the three projects.
They are cleaned datacube, which contain 4 columns:
Column 1: The frequency bin
Column 2: The dec bin
Column 3: The ra bin
Column 4: intensity
The reference value for freq, ra, dec and its increment can be found
in the header of each file.
Objects:
-------------------------------------------------
RA (2000) DE Designation(s)
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04 32 30.33 +17 31 40.8 GG Tau A = V* GG Tau
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 171 2 List of fits datacubes
fits/* . 2 Individual fits datacubes
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Byte-by-byte Description of file: list.dat
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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- 31 I2 --- Nz Number of pixels along Z-axis
33- 39 F7.2 m/s bVRAD Lower value of VRAD interval
41- 48 F8.2 m/s BVRAD Upper value of VRAD interval
50- 56 F7.3 m/s dVRAD VRAD resolution
58- 63 I6 Kibyte size Size of FITS file
65- 79 A15 --- FileName Name of FITS file, in subdirectory fits
81-171 A91 --- Title Title of the FITS file
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Acknowledgements:
Nguyen Thi Phuong, thi-phuong.nguyen(at)u-bordeaux.fr
(End) Patricia Vannier [CDS] 07-Feb-2020