J/A+A/570/A113 Herschel/PACS imaging of π1 Gru (HIP110478) (Mayer+, 2014)
Large-scale environments of binary AGB stars probed by Herschel.
II. Two companions interacting with the wind of pi1 Gruis
Mayer A., Jorissen A., Paladini C., Kerschbaum F., Pourbaix D., Siopis C.,
Ottensamer R., Mecina M., Cox N.L.J., Groenewegen M.A.T., Klotz D.,
Sadowski G., Spang A., Cruzalebes P., Waelkens C.
<Astron. Astrophys. 570, A113 (2014)>
=2014A&A...570A.113M 2014A&A...570A.113M
ADC_Keywords: Stars, giant ; Infrared sources
Keywords: stars: AGB and post-AGB - binaries: general - circumstellar matter -
stars: winds, outflows - stars: individual: pi1 Gru -
infrared: stars
Abstract:
The Mass loss of Evolved StarS (MESS) sample observed with PACS on
board the Herschel Space Observatory revealed that several asymptotic
giant branch (AGB) stars are surrounded by an asymmetric circumstellar
envelope (CSE) whose morphology is most likely caused by the
interaction with a stellar companion. The evolution of AGB stars in
binary systems plays a crucial role in understanding the formation of
asymmetries in planetary nebulae (PNe), but at present, only a handful
of cases are known where the interaction of a companion with the
stellar AGB wind is observed.
We probe the environment of the very evolved AGB star pi1 Gruis on
large and small scales to identify the triggers of the observed
asymmetries.
Description:
Deconvolved Herschel/PACS images of pi1 Gru (HIP 110478) at 70 and
160um with pixel sizes of 1" and 2", respectively. Both images cover a
field of view of 10'x10' centred on the star. The maps were produced
with the Herschel Interactive Processing Environment following
Groenewegen et al. (2011A&A...526A.162G 2011A&A...526A.162G), Scanamorphos following
Roussel (2013PASP..125.1126R 2013PASP..125.1126R), and subsequently deconvolved using a
maximum entropy method. The 70mu image reveals that the star is
surrounded by an asymmetric emission with a diameter of approx. 2'.
Two features are recognised, (i) an elliptical emission which
represents the dusty counterpart of a known CO disc (e.g. Chiu et al.
2006ApJ...645..605C 2006ApJ...645..605C), and (ii) an arc east of the star which is, most
likely, part of a spiral pattern.
Objects:
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RA (ICRS) DE Designation(s)
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22 22 44.21 -45 56 52.6 pi.1 Gru = HIP 110478
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 98 2 List of FITS images
images/* . 2 Individual FITS images (at 70 and 160µm)
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See also:
VI/139 : Herschel Observation Log (Herschel Science Centre, 2013)
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 GLON Galactic longitude
10- 18 F9.5 deg GLAT Galactic latitude
20 I1 arcsec/pix Scale [1/2] Scale of the image
22- 24 I3 --- Nx [300/600] Number of pixels along X-axis
25 A1 --- --- [x]
26- 28 I3 --- Ny [300/600] Number of pixels along Y-axis
30- 33 I4 Kibyte size [746/2800] Size of FITS file
35- 47 A13 --- FileName Name of FITS file in subdirectory images
49- 51 I3 um lambda [70/160] PACS filter (wavelength)
53- 98 A46 --- Title Title of the file
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Acknowledgements:
Andreas Mayer, a.mayer (at) univie.ac.at
References:
Mayer et al., Paper I. 2013A&A...549A..69M 2013A&A...549A..69M
(End) Andreas Mayer [Univ. of Vienna, IfA], Patricia Vannier [CDS] 12-Aug-2014