J/A+A/678/A55 Molecular gas in AFGL 2298 (Rizzo+, 2023)
The rich molecular environment of the luminous blue variable star AFGL 2298.
Rizzo J.R., Bordiu C., Buemi C., Leto P., Ingallinera A., Bufano F.,
Umana G., Cerrigone L., Trigilio C.
<Astron. Astrophys. 678, A55 (2023)>
=2023A&A...678A..55R 2023A&A...678A..55R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Stars, blue ; Stars, luminous ;
Spectra, radio ; Molecular data
Keywords: circumstellar matter - stars: evolution -
stars: individual: AFGL 2298 - stars: mass-loss - ISM: molecules
Abstract:
We investigated the molecular environment of AFGL 2298, an obscured
Galactic Luminous blue variable (LBV) star which hosts a highly
structured circumstellar environment with hints of multiple mass-loss
events in the last few 104a. We present spectral line observations
of AFGL 2298 at 1 and 3mm performed with the IRAM 30m radio telescope.
We report the detection of several carbon- and nitrogen- bearing
species (CO, 13CO, C18O, C17O, HCO+, HCN, HNC, H13CO+, CN,
N2H+, and C2H) in the surroundings of AFGL 2298. The molecular
emission is concentrated in three velocity components that clearly
stand out from the Galactic background. The morphology, kinematics,
masses and isotopic ratios, together with a comparative study of the
fractional abundances, lead us to suggest that two of these components
(36 and 70km/s) have a stellar origin. The other component (46 km/s)
most likely traces swept-up interstellar material, probably harboring
also a photon-dominated region. The first inventory of the
circumstellar molecular gas around AFGL 2298 is provided. The results
are compatible with the hypothesis of former mass-loss events,
produced before the one that created the infrared nebula. There are
chemical hints of the presence of ejected stellar material, and also
swept up gas. These findings will help to better understand the
mass-loss history of this class of evolved massive stars, which
heavily influence the overall chemical evolution of the Galaxy.
Description:
Molecular emission toward the star position (Figs. 1 and 4) are in
FITS files which contain the collection of spectra.
Data cubes of the CO isotopologues are also included, in the form of
FITS files.
Tables 3 and 4 of the paper, containing column densities and
abundances, are also included.
Objects:
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RA (2000) DE Designation(s)
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19 00 10.89 +03 45 47.1 AFGL 2298 = IRAS 18576+0341
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 96 8 List of fits datacubes
image/* . 8 Individual fits datacubes
listsp.dat 72 17 List of spectra
fig1.fits 2880 17 Molecular emission toward the star position
(fig. 1)
fig4.fits 2880 13 Molecular emission toward the star position
(fig. 4)
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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- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 29 I4 --- Nz Number of slices
31- 39 F9.1 m/s bVRAD Lower value of Vrad interval
41- 46 I6 m/s BVRAD Upper value of Vrad interval
48- 54 F7.3 m/s dVRAD Vrad resolution
56- 59 I4 Kibyte size Size of FITS file
61- 73 A13 --- FileName Name of FITS file, in subdirectory image
75- 96 A22 --- Title Title of the FITS file
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Byte-by-byte Description of file: listsp.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Line Line
14- 24 E11.6 Hz Restfreq Rest frequency
26- 36 E11.6 Hz Imagefreq Image frequency
38- 49 E12.6 m/s DeltaV Velocity resolution
51- 60 A10 "date" Obs.date Observation date
62- 70 A9 --- FileName Name of the fits file with spectrum
72 I1 --- Rank Line number in the fits table
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Acknowledgements:
Ricardo Rizzo, ricardo.rizzo(at)cab.inta-csic.es
(End) Ricardo Rizzo [CAB, Spain], Patricia Vannier [CDS] 14-Sep-2023