J/A+A/489/1271 CO and OH abundances of 23 K-M giants (Tsuji, 2008)
Cool luminous stars: the hybrid nature of their infrared spectra.
Tsuji T.
<Astron. Astrophys. 489, 1271 (2008)>
=2008A&A...489.1271T 2008A&A...489.1271T
ADC_Keywords: Stars, giant ; Spectra, infrared ; Abundances
Keywords: line: formation - stars: abundances - stars: late-type -
stars: atmospheres - stars: mass-loss - infrared: stars
Description:
Based on the high resolution infrared spectra observed with the
Fourier Transform Spectrometer (FTS) at the 4m telescope of the Kitt
Peak National Observatory (KPNO), ro-vibrational lines of 12C16O,
13C16O, 12C17O, and 16OH were measured. Some details of the
observed spectra including the resolution, S/N ratio, and data of
observation are given in table2. The spectroscopic and equivalent
width data are given in table3 for 23 red giant stars.
The resulting data are used to investigate the nature of the infrared
spectra of K-M giant stars. It is found that only the weak lines
(log(W/nu)←4.75) carry the information on the photosphere and hence
can be used to extract the nature of the photosphere such as the
stellar abundances. The intermediate-strength (-4.75<log(W/nu)←4.40)
as well as the strong (log(W/nu)>-4.4) lines are badly disturbed by
the lines of non-photospheric origin. In other words, most lines
dominating the infrared spectra, except for the weak lines, are
actually hybrid of at least two different kinds of lines originating
in the photosphere and in an extra molecular layers outside of
photosphere. The nature of the extra layers is not known well, but it
may be related to the molecular envelope producing H2O lines, not
only in late M but also in early M giants as well. Also, the
intermediate-strength lines include those with LEP as high as 2eV and
hence the extra molecular layer should be quite warm.
For the reason outlined above, we determine C, O, and their isotopic
abundances using only the weak lines, but we listed the measured data
not only of the weak lines but also of the stronger lines as well in
table3, with the hope that these data can be of some use to clarify
the nature of the warm extra molecular layers.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 50 39 Observed spectra of the 23 program stars
table3.dat 78 2880 *Equivalent width data of CO and OH
ftsdata/* . 42 FTS spectra, fortran program and readme
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Note on table3.dat: No HO data for BS6861, OP Her and XY Lyr
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Identification of program star
11- 13 A3 --- SpReg Spectral region defined by the filter band
20- 24 F5.2 dam-1 R Resolution of the spectrum (1)
28- 30 I3 --- S/N ?=- Signal-to-noise ratio of the spectrum
34- 43 A10 "YYYY/MM/DD" Obs.Date Date of observation
45- 50 A6 --- FileName Name of the FTS spectra file in
subdirectory ftsdata
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Note (1): Resolution R is defined by R=1/2L, where L is the maximum
path difference (in cm) of the interferometer, expressed in mk
(1mk=0.001cm-1)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Identification of program star
13- 18 A6 --- Ion Identification of the isotopic species (1)
22 I1 --- v' Quantum number of the upper vibrational level
26 I1 --- v" Quantum number of the lower vibrational level
30- 38 A9 --- Trans Identification of the rotational transition
43- 50 F8.3 cm-1 nu Wave number of the line
53- 58 F6.3 [-] loggf Logarithm of the gf-value
62- 70 F9.3 cm-1 LEP Lower excitation potential
73- 78 F6.3 [-] log(W/nu) Logarithm of the equivalent width to wavenumber
ratio (2)
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Note (1): Isotopic species are C12O16, C12O17, C13O16 and O16H
Note (2): Where the equivalent width W is in unit of cm-1.
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Acknowledgements:
Takashi Tsuji,
(End) Patricia Vannier [CDS] 25-Jun-2008