J/A+A/684/A4 ALMA spectral surveys of C-rich AGB stars (Unnikrishnan+, 2024)
Charting Circumstellar Chemistry of Carbon-rich AGB Stars:
I. ALMA 3 mm spectral surveys.
Unnikrishnan R., De Beck E., Nyman L.A., Olofsson H., Vlemmings W.H.T.,
Tafoya D., Maercker M., Charnley S.B., Cordiner M.A., de Gregorio I.,
Humphreys E., Millar T.J., Rawlings M.G.
<Astron. Astrophys. 684, A4 (2024)>
=2024A&A...684A...4U 2024A&A...684A...4U (SIMBAD/NED BibCode)
ADC_Keywords: Stars, carbon ; Stars, giant ; Stars, radio ; Mass loss ;
Spectra, millimetric/submm ; Abundances; Interferometry
Keywords: astrochemistry - stars: AGB and post-AGB - circumstellar matter -
stars: mass-loss - stars: winds, outflows - submillimeter: stars
Abstract:
Asymptotic giant branch (AGB) stars are major contributors to the
chemical enrichment of the ISM through nucleosynthesis and extensive
mass loss. Most of our current knowledge of AGB atmospheric and
circumstellar chemistry, in particular in a C-rich environment, is
based on observations of the carbon star IRC+10216. We aim to obtain a
more generalised understanding of the chemistry in C-rich AGB CSEs by
studying a sample of three carbon stars, IRAS 15194-5115, IRAS
15082-4808, and IRAS 07454-7112, and test the archetypal status often
attributed to IRC+10216. We performed spatially resolved, unbiased
spectral surveys in ALMA Band 3. We identify a total of 132 rotational
transitions from 49 molecular species. We find that, within the
uncertainties of the analysis, the observed circumstellar chemistry
appears very similar across our sample and compared to that of
IRC+10216, both in terms of the relative location of the emitting
regions and molecular abundances. This implies that, to a first
approximation, the chemical models tailored to IRC+10216 are able to
reproduce the observed chemistry in C-rich envelopes across roughly an
order of magnitude in wind density.
Description:
Data for three C-type AGB stars,
IRAS 15194-5115, IRAS 15082-4808, and IRAS 07454-7112.
3D line cubes of the emission lines observed using ALMA, maps of the
continuum emissions, and the full ALMA Band 3 spectra for each of the
three stars, in FITS format.
Objects:
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RA (2000) DE Designation(s)
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15 23 05.07 -51 25 58.7 IRAS 15194-5115 = V* II Lup
15 11 41.44 -48 19 58.9 IRAS 15082-4808 = V* V358 Lup
07 45 02.41 -71 19 45.8 IRAS 07454-7112 = V* AI Vol
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
listsp.dat 130 3 List of fits spectra
sp/* . 3 Individual fits spectra
listmap.dat 147 3 List of fits maps of the continuum emissions
maps/* . 3 Individual fits maps
listcube.dat 199 359 List of fits 3D line cubes of the emission
lines observed using ALMA
cubes/* . 359 Individual fits datacubes
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Byte-by-byte Description of file: listsp.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 I5 --- Nx Number of pixels along X-axis
26- 33 F8.5 GHz bFREQ Lower value of frequency interval
35- 41 F7.4 GHz BFREQ Upper value of frequency interval
43- 48 I6 Hz dFREQ Frequency resolution
50- 52 I3 Kibyte size Size of FITS file
54- 93 A40 --- FileName Name of FITS file, in subdirectory sp
95-130 A36 --- Title Title of the FITS file
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Byte-by-byte Description of file: listmap.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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 Observation date
55- 58 I4 Kibyte size Size of FITS file
60-108 A49 --- FileName Name of FITS file, in subdirectory maps
110-147 A38 --- Title Title of the FITS file
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Byte-by-byte Description of file: listcube.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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 pixels along Z-axis
34- 59 A26 "datime" Obs.date Observation date
61- 69 F9.1 m/s bVRAD ? Lower value of VRAD interval
71- 81 F11.3 m/s BVRAD ? Upper value of VRAD interval
83- 89 F7.2 m/s dVRAD ? VRAD resolution
91- 96 I6 Kibyte size Size of FITS file
98-147 A50 --- FileName Name of FITS file, in subdirectory cubes
149-199 A51 --- Title Title of the FITS file
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History:
From Ramlal Unnikrishnan Nair, ramlal.unnikrishnan(at)chalmers.se
Acknowledgements:
RU acknowledges data reduction support from the Nordic ALMA Regional
Centre (ARC) node based at Onsala Space Observatory (OSO), Sweden. The
Nordic ARC node is funded through Swedish Research Council grant No
2017-00648. EDB acknowledges financial support from the Swedish
National Space Agency. SBC and MAC were supported by the NASA
Planetary Science Division Internal Scientist Funding Program through
the Fundamental Laboratory Research work package (FLaRe). IdG
acknowledges support from grant PID2020-114461GB-I00, funded by
MCIN/AEI/10.13039/501100011033. The work of MGR is supported by
NOIRLab, which is managed by the Association of Universities for
Research in Astronomy (AURA) under a cooperative agreement with the
National Science Foundation, USA. This paper makes use of the
following ALMA data: ADS/JAO.ALMA#2013.1.00070.S,
ADS/JAO.ALMA#2015.1.01271.S, ADS/JAO.ALMA#2011.0.00001.CAL. ALMA is
a partnership of ESO (representing its member states), NSF (USA) and
NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and
KASI (Republic of Korea), in cooperation with the Republic of Chile.
The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. This
paper is based on observations with the Atacama Pathfinder EXperiment
(APEX) telescope. APEX is a collaboration between the Max Planck
Institute for Radio Astronomy, the European Southern Observatory, and
the Onsala Space Observatory. Swedish observations on APEX are
supported through Swedish Research Council grant No 2017-00648. The
APEX observations were obtained under project numbers O-0107.F-9310
(SEPIA/B5), O-0104.F-9305 (PI230), and O-087.F-9319, O-094.F-9318,
O-096.F-9336, and O-098.F-9303 (SHeFI).
(End) Patricia Vannier [CDS] 23-Dec-2023