J/A+A/624/A107 IK Tau & IRC+10011 interferometric observations (Verbena+, 2019)
Interferometric observations of SiO thermal emission in the inner wind of
M-type AGB stars IK Tauri and IRC+10011.
Verbena J.L., Bujarrabal V., Alcolea J., Gomez-Garrido M., Castro-Carrizo A.
<Astron. Astrophys. 624, A107 (2019)>
=2019A&A...624A.107V 2019A&A...624A.107V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Stars, M-type ; Spectra, millimetric/submm
Keywords: stars: AGB and post-AGB - stars: mass-loss - stars: late-type -
circumstellar matter - radio lines: stars
Abstract:
AGB stars go through a process of strong mass-loss that involves
pulsations of the atmosphere, which extends to a region where the
conditions are adequate for dust grains to form. Radiation pressure
acts on these grains which, coupled to the gas, drive a massive
outflow. The details of this process are not clear, including which
molecules are involved in the condensation of dust grains.
To study the role of the SiO molecule in the process of dust formation
and mass-loss in M-type AGB stars.
Using the IRAM NOEMA interferometer we observed the 28SiO and
29SiO J=3-2, v=0 emission from the inner circumstellar envelope of
the evolved stars IK Tau and IRC+10011. We computed azimuthally
averaged emission profiles to compare the observations to models using
a molecular excitation and ray-tracing code for SiO thermal emission.
We observed circular symmetry in the emission distribution. We also
found that the source diameter varies only marginally with radial
velocity, which is not the expected behavior for envelopes expanding
at an almost constant velocity. The adopted density, velocity, and
abundance laws, together with the mass-loss rate, which best fit the
observations, give us information on the chemical behavior of the SiO
molecule and its role in the dust formation process.
The results indicate that there is a strong coupling between the
depletion of gas phase SiO and gas acceleration in the inner envelope.
This could be explained by the condensation of SiO into dust grains.
Description:
Observations at 130.269 and 128.637GHz in a window of 110MHz. These
are the rest frequencies of the J=3-2, v=0 emission lines for 28SiO
and 29SiO. The observed objects are evolved M-type stars IK Tauri
and IRC+10011.
Objects:
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RA (2000) DE Designation(s)
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03 53 28.89 +11 24 21.9 IK Tau = V* IK Tau
01 06 25.99 +12 35 52.9 IRC+10011 = V* WX Psc
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 131 4 List of datacubes
fits/* . 4 Individual data cubes
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See also:
J/A+A/597/A25 : IK Tau millimeter IRAM-30m line survey (Velilla Prieto+, 2017)
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- 32 I3 --- Nz Number of slices
34- 43 F10.6 MHz RestFreq Rest frequency
45- 50 I6 m/s bVRAD Lower value of VRAD interval
52- 56 I5 m/s BVRAD Upper value of VRAD interval
58- 60 I3 m/s dVRAD VRAD resolution
62- 67 I6 Kibyte size Size of FITS file
69-100 A32 --- FileName Name of FITS file, in subdirectory fits
102-131 A30 --- Title Title of the FITS file
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Acknowledgements:
Juan Luis Verbena, jl.verbena(at)csic.es
(End) Juan Luis Verbena [Madrid, Spain], Patricia Vannier [CDS] 12-Mar-2019