J/A+A/368/250 Abundances of HDE 341617 (Arellano Ferro+, 2001)
Atmospheric abundances in post-AGB candidates of intermediate temperature
Arellano Ferro A., Giridhar S., Mathias P.
<Astron. Astrophys. 368, 250 (2001)>
=2001A&A...368..250A 2001A&A...368..250A
ADC_Keywords: Protostars ; Planetary nebulae ; Equivalent widths ;
Radial velocities
Keywords: stars: post-AGB - stars: chemically peculiar - stars: evolution
Abstract:
Detailed atmospheric abundances have been calculated for a sample of
A-G supergiant stars with IR fluxes and/or high galactic latitudes.
HD 172481 and HD 158616 show clear indications of being post-AGB stars
that have experienced third dredge-up. HD 158616 is carbon-rich while
the abundance pattern of HD 172481 and its large Li enhancement gives
support to the hot bottom burning scenario that explains paucity of
carbon-rich stars among AGB stars. HD 172324 is very likely a hot
post-AGB star that shows a strong carbon deficiency. HD 725, HD 218753
and HD 331319 also appear to be evolved objects between the red giant
and the AGB. HD 9167, HD 173638 with a few exceptions, reflect solar
abundances and no signs of post red giant evolution. They are most
likely young massive disk supergiants. Further analysis of
proto-Planetary Nebula HDE 341617 reveals that He lines show signs of
velocity stratification. The emission lines have weakened considerably
since 1993. The envelope expands at 19km/s relative to the star.
Atmospheric abundances, evolutionary tracks and isochrones are used to
estimate masses and ages of all stars in the sample.
Description:
Table 11.dat: Several absorption lines of He I, O II, Si III and Fe II
are detected. The radial velocity, for each individual line
unambiguously identified is given. For He I two groups of lines are
identified at average velocities of 52.6±8.3km/s (4 lines) and
75.0±3.7km/s (4 lines). This suggests some stratification in the
atmosphere. The rest of the species however average 73.3±2.9km/s (15
lines). The low dispersion in the radial velocity suggests that all
these lines are formed in the same region of the stellar atmosphere
and no stratification is evident.
Table 12.dat: the emission spectrum, formed in the outer envelope
and/or in the nebulosity, consists of lines of Fe II, [Fe II], Fe III,
[S II], O I, [N II] and Si II. The radial velocities of emission lines
are all very consistent and average 54.3±3.4km/s. The difference of
radial velocities between the absorption and emission lines indicates
that the nebulosity expands at about 19km/s. The Balmer lines show
emission on top of the stellar absorption. The emission is shifted
relative to the absorption and is consistent with the radial
velocities of other emission features, showing that it is also
produced in the same region.
Objects:
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RA (2000) DE Designation(s)
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18 08 20.1 +24 10 43 HDE 341617
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table11.dat 54 27 Absorption lines identified in the spectrum of
the proto-Planetary Nebula HDE 341617.
table12.dat 56 84 Emission lines identified in the spectrum of the
proto-Planetary Nebula HDE 341617
tables.tex 102 182 LaTeX version of the tables
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Byte-by-byte Description of file: table11.dat table12.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Ion Ion designation
16- 23 F8.3 0.1nm lambdaObs Observed wavelength
25- 32 F8.3 0.1nm lambdaLab ? Laboratory wavelength (1)
33 A1 --- n_lambdaLab [/+] Note on lambdaLab2 (2)
34- 41 F8.3 0.1nm lambdaLab2 ? Second value of laboratory wavelength (2)
43- 49 F7.2 0.1pm EW ? Equivalent width
51- 55 F5.2 km/s RV ? Radial velocity
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Note (1): uf: unidentified feature
Note (2): For O II+C III, LambdaLab = 4673.91 /4673.75
For He Ibld, LambdaLab = 5875.618+5875.650
For O I, LambdaLab =5958.46 +5958.630
For O I bld, LambdaLab = 6046.26 +6046.46
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Acknowledgements: A. Arellano Ferro
(End) Patricia Bauer [CDS] 19-Jan-2001