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J/A+A/600/A71       C17O and C18O spectra of nine AGB stars    (De Nutte+, 2017)

Nucleosynthesis in AGB stars traced by oxygen isotopic ratios I. Determining the stellar initial mass by means of the 17O/18O ratio. De Nutte, Decin L., Olofsson H., Lombaert R., de Koter A., Karakas A., Milam S., Ramstedt S., Stancliffe R.J., Homan W., Van de Sande M. <Astron. Astrophys. 600, A71 (2017)> =2017A&A...600A..71D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Spectra, millimetric/submm Keywords: stars: AGB and post-AGB - stars: evolution - stars: fundamental parameters - circumstellar matter Abstract: We seek to investigate the 17O/18O ratio for a sample of AGB stars containing M-, S-, and C-type stars. These ratios are evaluated in relation to fundamental stellar evolution parameters: the stellar initial mass and pulsation period. Circumstellar 13C16O, 12C17O, and 12C18O line observations were obtained for a sample of nine stars with various singledish long-wavelength facilities. Line intensity ratios are shown to relate directly to the surface 17O/18O abundance ratio. Stellar evolution models predict the 17O/18O ratio to be a sensitive function of initial mass and to remain constant throughout the entire TP-AGB phase for stars initially less massive than 5 solar masses. This makes the measured ratio a probe of the initial stellar mass. Observed 17O/18O ratios are found to be well in the range predicted by stellar evolution models that do not consider convective overshooting. From this, accurate initial mass estimates are calculated for seven sources. For the remaining two sources, there are two mass solutions, although there is a larger probability that the low-mass solution is correct. Finally, we present hints at a possible separation between M/S- and C-type stars when comparing the 17O/18O ratio to the stellar pulsation period. Description: The data presented in this study were obtained with three different telescopes. The Institut de Radio Astronomie Millimetrique (IRAM) 30m telescope at Pico Veleta, Spain (Program ID 042-12, 164-12) using the EMIR heterodyne receiver in dual band observation mode in the E0(90GHz)/E2(230GHz) configuration; the Atacama Pathfinder EXperiment(APEX) 12m telescope on the Chajnantor Plateau, Chile (Program ID 090.D-0290, 091.D-0813, 094.D-0851A), in the SHeFI 230GHz band, and the Caltech Submillimeter Observatory (CSO) at Mauna Kea, Hawaii, using the 230GHz receiver. The sources were observed using position switching or wobbler switching mode to attain flat baselines. The pointing of the telescope was checked repeatedly throughout the observations using strong CO and continuum sources. The reduction and analysis of all data were performed using the GILDAS CLASS software package. After removing faulty scans and spikes, a firstorder polynomial baseline was subtracted from each scan. The individual baseline-subtracted scans obtained for a given source were then averaged using an inverse quadratic system temperature weighting. Finally the data were rebinned to obtain a suitable signal-to-noise ratio (S/N), generally S/N=3-5 for a velocity resolution of 2km/s (the typical linewidth being around 20-40km/s). Objects: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 19 50 33.92 +32 54 50.6 chi Cyg = HD 187796 09 47 57.41 +13 16 43.6 CW Leo = PN G221.4+45.0 06 52 47.04 +08 25 19.1 GX Mon = SV* SON 4010 23 19 12.61 +17 11 33.1 LL Peg = PN G093.5-40.3 23 34 27.53 +43 33 01.2 LP And = RAFGL 3116 10 16 02.28 +30 34 19.0 RW LMi = PN G197.7+55.9 03 26 29.51 +47 31 48.6 V384 Per = SV* SVS 1809 19 15 23.35 -07 02 50.3 W Aql = RAFGL 2349 01 06 25.98 +12 35 53.0 WX Psc = PN G128.6-50.1 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 128 22 list of spectra sp/* 0 22 Individual spectrum fits files
Byte-by-byte Description of file: list.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- 21 I2 --- Nx Number of pixels along X-axis 23- 45 A23 --- Observation date (YYYY-MM-DDThh:mm:ss.sss) 47- 58 E12.6 Hz bFreq Lower value of frequency interval 60- 70 E11.6 Hz BFreq Upper value of frequency interval 72- 82 E11.6 Hz dFreq Frequency resolution 84 I1 Kibyte size Size of FITS file 86- 97 A12 --- FileName Name of FITS file, in subdirectory sp 99-128 A30 --- Title Title of the FITS file
Acknowledgements: Rutger De Nutte, rutger.denutte(at)
(End) Patricia Vannier [CDS] 09-Feb-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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