J/A+A/513/A53 LABOCA 870um images of evolved stars (Ladjal+, 2010)
870um observations of evolved stars with LABOCA.
Ladjal D, Justtanont K., Groenewegen M.A.T., Blommaert J.A.D.L.,
Waelkens C., Barlow M.J.
<Astron. Astrophys. 513, A53 (2010)>
=2010A&A...513A..53L 2010A&A...513A..53L
ADC_Keywords: Stars, supergiant ; Millimetric/submm sources
Keywords: stars: AGB and post-AGB - stars: late-type - circumstellar matter -
submillimeter: genenral - stars: mass-loss - dust - extinction
Abstract:
During their evolution, Asymptotic Giant Branch (AGB) stars experience
a high mass-loss which leads to the formation of a circumstellar
envelope (CSE) of dust and gas. The mass loss process is the most
important phenomenon during this evolutionary stage. In order to
understand it, it is important to study the physical parameters of the
CSE. The emission of the CSE in the (sub)millimetre range is dominated
by the dust continuum. This means that (sub)millimetre observations
are a key tool in tracing the dust and improving our knowledge of the
mass-loss process. We analysed new sub-millimetre observations of 9
evolved stars in order to constrain the CSE physical parameters. The
data were taken by the new APEX bolometer LABoCa. The fluxes at 870 um
are derived and the extended emission is investigated. We computed the
spectral energy distribution (SEDs) with the 1D radiative transfer
code DUSTY, which we compared to literature data. Grain properties
were calculated with both a spherical grains distribution and a
continuous distribution of ellipsoids (CDE), and a comparison between
the two is drawn. Synthetic surface brightness maps were derived from
the modelling and were compared to the LABoCa brightness maps. We
detected the presence of extended emission around four stars. Physical
parameters of the circumstellar envelope were derived from SED
modelling, like the dust chemical composition, the dust condensation
temperature and the total mass of the envelope.
Description:
870 um LABOCA observations of a sample of 9 evolved stars. The data
are the reduced and calibrated data as used in the paper. For the data
reduction procedure see the paper. The raw data with the calibration
files can be retrieved from the ESO archive.
The images are in Jy/pixel with a pixel size of 6.07arcsec.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
objects.dat 55 9 List of objects
images/* . 9 LABoCa images in FITS format
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Byte-by-byte Description of file: objects.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Object name
17- 18 I2 h RAh Right ascension J2000 (hours)
20- 21 I2 min RAm Right ascension J2000 (minutes)
23- 26 F4.1 s RAs Right ascension J2000 (seconds)
28 A1 --- DE- Declination J2000 (sign)
29- 30 I2 deg DEd Declination J2000 (degrees)
32- 33 I2 arcmin DEm Declination J2000 (minutes)
35- 38 F4.1 arcsec DEs Declination J2000 (seconds)
43- 55 A13 --- FileName Name of the FITS file, in "images" subdirectory
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Acknowledgements:
Djazia Ladjal, djazzzia(at)yahoo.fr
(End) D. Ladjal [KU Leuven], Patricia Vannier [CDS] 27-Jan-2010