J/A+A/605/A116 ALMA FITS cubes of CO(1-0) and CO(2-1) (Kerschbaum+, 2017)
Rings and filaments. The remarkable detached CO shell of U Antliae.
Kerschbaum F., Maercker M., Brunner M., Lindqvist M., Olofsson H.,
Mecina M., De Beck E., Groenewegen M.A.T., Lagadec E., Mohamed S.,
Paladini C., Ramstedt S., Vlemmings W.H.T., Wittkowski M.
<Astron. Astrophys. 605, A116 (2017)>
=2017A&A...605A.116K 2017A&A...605A.116K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, carbon ; Radio lines ; Carbon monoxide
Keywords: stars: AGB and post-AGB - stars: carbon - stars: evolution -
stars: mass loss
Abstract:
Our goal is to characterize the intermediate age, detached shell
carbon star U Antliae morphologically and physically in order to study
the mass-loss evolution after a possible thermal pulse.
High spatial resolution ALMA observations of unprecedented quality in
thermal CO lines allow us to derive first critical spatial and
temporal scales and constrain modeling effects to estimate mass-loss
rates for both the present day as well as the ejection period of the
detached shell.
The detached shell is remarkably thin, overall spherically symmetric,
and shows a barely resolved filamentary substructure possibly caused
by instabilities in the interaction zone of winds with different
outflow velocities. The expansion age of the detached shell is of the
order of 2700 years and its overall width indicates a high
expansion-velocity and high mass-loss period of only a few hundred
years at an average mass-loss rate of ∼10-5M☉/yr. The
post-high-mass-loss-rate-epoch evolution of U Ant shows a significant
decline to a substantially lower gas expansion velocity and a
mass-loss rate amounting to 4x10-8M☉/yr, at present being
consistent with evolutionary changes as predicted for the period
between thermal pulses.
Description:
FITS image cubes of the CO(1-0) and CO(2-1) molecular line
observations around the carbon AGB star U Antliae.
The circumstellar envelope has been observed with ALMA (12m array +
ACA + TP) in a mosaic of 110 x 110 arcseconds.
The velocity resolution after binning is 1km/s, the systemic velocity
is at 24.5km/s.
Objects:
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RA (2000) DE Designation(s)
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10 35 12.85 -39 33 45.3 U Ant = HR 4153
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 144 2 List of data cubes
fits/* . 2 Individual 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)
21- 23 I3 --- Nx Number of pixels along X-axis
25- 27 I3 --- Ny Number of pixels along Y-axis
29- 30 I2 --- Nz Number of slices
32- 54 A23 --- Obs.Date Observation date 'YYYY-MM-DDThh:mm:ss.sss)
56- 66 E11.6 Hz bFreq Lower value of frequency interval
68- 78 E11.6 Hz BFreq Upper value of frequency interval
80- 85 I6 Hz dFreq Frequency resolution
87- 92 I6 Kibyte size Size of FITS file
94-104 A11 --- FileName Name of FITS file, in subdirectory fits
106-144 A39 --- Title Title of the FITS file
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Acknowledgements:
Franz Kerschbaum, franz.kerschbaum(at)univie.ac.at
(End) Patricia Vannier [CDS] 17-Aug-2017