J/A+A/621/A50 TX Psc ALMA CO(2-1) images (Brunner+, 2019)
ALMA observations of the "fresh" carbon-rich AGB star TX Piscium.
The discovery of an elliptical detached shell.
Brunner M., Mecina M., Maercker M., Dorfi E.A., Kerschbaum F., Olofsson H.,
Rau G.
<Astron. Astrophys. 621, A50 (2019)>
=2019A&A...621A..50B 2019A&A...621A..50B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, carbon ; Stars, late-type ; Carbon monoxide
Keywords: stars: AGB and post-AGB - stars: carbon - stars: evolution -
stars: mass-loss - stars: late-type
Abstract:
We observed the carbon-rich asymptotic giant branch (AGB) star
TX Piscium (TX Psc) with ALMA in CO(2-1) emission to investigate the
circumstellar envelope (CSE) and mass-loss history of this object.
Previous observations with Herschel in the far infrared have shown a
ring-like structure in dust emission (2011A&A...532A.135J 2011A&A...532A.135J). Our
molecular gas observations of the CO(2-1) emission line cover this
structure with significantly higher spatial resolution to investigate
its origin.
Description:
The datacubes show the CO(2-1) gas distribution in the CSE of TX Psc
as observed by ALMA with the main array (12 antennas) and the Atacama
Compact Array (ACA, 7m antennas). The images have been created with
CASA by face-to-face support of the Nordic ARC Node and give mosaics
with a size of 45"x45" and a resolution of 1" for the main array and a
beamsize of 7.6"x 4.44" for the ACA. The spectral resolution is
0.65km/s (499.84kHz) for he CO(2-1) line at a frequency of rest of
230.538GHz. The stellar velocity is roughly at 13km/s, marking the
center velocity. In both datacubes two components are detected in the
CSE: a strong and compact present-day wind close to the stellar
position, and a larger shell structure with a maximum radius of
roughly 17", which is of elliptical shape. Similar detached shell
structures are usually detected only with spherical shapes, while the
axis ratio of our elliptical shell is 1.3 and therefore shows a clear
deviation from spherical symmetry.
Objects:
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RA (2000) DE Designation(s)
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23 46 23.51 +03 29 12.5 TX Psc = * 19 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 164 2 List of fits images
fits/* . 2 Individual fits images
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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- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 53 A26 "datime" Obs.date Onservations date (YYYY-MM-DDTHH:MM:SS.ssssss)
55- 61 F7.3 GHz bFreq [230.516] Lower value of frequency interval
63- 69 F7.3 GHz BFreq [230.538] Upper value of frequency interval
71- 76 I6 Hz dFreq [499845] Frequency resolution
78- 82 I5 Kibyte size [47118] Size of FITS file
84-113 A30 --- FileName Name of FITS file, in subdirectory fits
115-164 A50 --- Title Title of the FITS file
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Acknowledgements:
Magdalena Brunner, magdalena.brunner(at)univie.ac.at
(End) Patricia Vannier [CDS] 12-Nov-2018