J/ApJ/825/38 Carbon and oxygen isotopic ratios for nearby Miras (Hinkle+, 2016)
Carbon and oxygen isotopic ratios for nearby Miras.
Hinkle K.H., Lebzelter T., Straniero O.
<Astrophys. J., 825, 38-38 (2016)>
=2016ApJ...825...38H 2016ApJ...825...38H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Abundances ; Interstellar medium ;
Spectra, infrared
Keywords: ISM: abundances; stars: abundances; stars: evolution;
stars: interiors; stars: variables: general
Abstract:
Carbon and oxygen isotopic ratios are reported for a sample of 46 Mira
and SRa-type variable asymptotic giant branch (AGB) stars.
Vibration-rotation first and second-overtone CO lines in 1.5-2.5µm
spectra were measured to derive isotopic ratios for 12C/13C,
16O/17O, and 16O/18O. Comparisons with previous measurements
for individual stars and with various samples of evolved stars, as
available in the extant literature, are discussed. Models for solar
composition AGB stars of different initial masses are used to
interpret our results. We find that the majority of M-stars have main
sequence masses ≤2M☉ and have not experienced sizable third
dredge-up (TDU) episodes. The progenitors of the four S-type stars in
our sample are slightly more massive. Of the six C-stars in the sample
three have clear evidence relating their origin to the occurrence of
TDU. Comparisons with O-rich presolar grains from AGB stars that lived
before the formation of the solar system reveal variations in the
interstellar medium chemical composition. The present generation of
low-mass AGB stars, as represented by our sample of long period
variables (LPVs), shows a large spread of 16O/17O ratios, similar
to that of group 1 presolar grains and in agreement with theoretical
expectations for the composition of mass 1.2-2M☉ stars after the
first dredge-up. In contrast, the 16O/18O ratios of present-day
LPVs are definitely smaller than those of group 1 grains. This is most
probably a consequence of the the decrease with time of the
16O/18O ratio in the interstellar medium due to the chemical
evolution of the Milky Way. One star in our sample has an O
composition similar to that of group 2 presolar grains originating in
an AGB star undergoing extra-mixing. This may indicate that the
extra-mixing process is hampered at high metallicity, or,
equivalently, favored at low metallicity. Similarly to O-rich grains,
no star in our sample shows evidence of hot bottom burning, which is
expected for massive AGB stars.
Description:
The observational material in this paper is drawn entirely from the
archives of the Kitt Peak National Observatory (KPNO) 4m Mayall
Telescope Fourier Transform Spectrometer (FTS). All the program stars
are AGB variables, restricted to those that are Mira and SRa
variables. The set of spectra spanned from 1976 May 12 to 1985 Sep 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 80 46 Isotopic ratios
table3.dat 37 236 CO Δv=2 best lines
table4.dat 37 400 CO Δv=3 best lines
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See also:
B/gcvs : General Catalogue of Variable Stars (GCVS) (Samus+ 2007-2013)
III/240 : Near-infrared spectra of MK standards (Wallace+ 1997-2002)
J/MNRAS/437/195 : Super and massive AGB stars nucleosynthesis (Doherty+, 2014)
J/A+A/548/A55 : C and O isotopic ratios in Arcturus and Aldebaran (Abia+ 2012)
J/A+A/531/A88 : Optical spectra of 12 Miras (Uttenthaler+, 2011)
J/ApJ/690/837 : CN and CO observations toward AGB stars (Milam+, 2009)
J/A+A/384/925 : Compiled catalog of stellar data of Miras (Kharchenko+, 2002)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/ApJS/111/445 : Spectra of normal stars in the K band (Wallace+ 1997)
J/ApJS/105/419 : Spectral Atlas of Carbon Stars (Barnbaum+ 1996)
http://fruity.oa-teramo.inaf.it/ : Full-network Repository of Updated Isotopic
Tables and Yields
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Stellar identifier
11- 17 A7 --- Type Stellar type
19- 21 I3 d Per [143/557] Period from the GCVS
22 A1 --- u_Per Uncertainty flag on Per
24- 27 F4.2 --- Phase1 [0/1]? Phase in the first observation
29- 32 F4.2 --- Phase2 [0.3/0.8]? Phase in the second observation
34 A1 --- f_Phase1 [:m] Flag on Phase 1 (1)
36- 39 I4 K T1 [2400/3800]? Temperature in the first observation
41- 44 I4 K T2 [2600/3200]? Temperature in the second observation
46- 48 I3 --- 12C/13C [8/224]? The 12C to 13C isotopic ratio
49 A1 --- u_12C/13C Uncertainty flag on 12C/13C
51- 53 I3 --- e_12C/13C [2/130]? Error in 12C/13C
56 A1 --- l_16O/17O Limit flag on 16O/17O
57- 60 I4 --- 16O/17O [100/4467]? The 16O to 17O isotopic ratio
61 A1 --- u_16O/17O Uncertainty flag on 16O/17O
63- 66 I4 --- e_16O/17O [30/1100]? Error in 16O/17O
68 A1 --- l_16O/18O Limit flag on 16O/18O
69- 72 I4 --- 16O/18O [71/5623]? The 16O to 18O isotopic ratio
73 A1 --- u_16O/18O Uncertainty flag on 16O/18O
75- 78 I4 --- e_16O/18O [25/2500]? Error in 16O/18O
80 A1 --- f_16O/18O [a] a = Ratio based on a single line
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Note (1): Flag as follows:
: = Uncertain value;
m = multiple observations.
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Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 cm-1 sigma [4001.7/6415.7] Wavenumber in vacuum
10- 17 F8.2 0.1nm lambda [15582.5/24982.4] Wavelength in air; Angstroms
19- 20 I2 --- Iso-C [12/13] Carbon isotope
22- 23 I2 --- Iso-O [16/18] Oxygen isotope
25- 26 I2 --- v1 [2/12] Transition upper v value
28 I1 --- v0 [0/9] Transition Lower v value
30 A1 --- TB [PR] Transition Branch
32- 34 I3 --- J0 [0/111] Transition lower J value
36- 37 I2 --- N [3/30] Number of spectra used
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Aug-2016