J/A+A/334/987 6 blue objects spectral data (Venn+ 1998)
New identifications for blue objects towards the Galactic center:
post-AGB stars, Be/disk stars, and others
Venn K.A., Smartt S.J., Lennon D.J., Dufton P.L.
<Astron. Astrophys. 334, 987 (1998)>
=1998A&A...334..987V 1998A&A...334..987V (SIMBAD/NED BibCode)
ADC_Keywords: Blue objects ; Stars, early-type ; Spectroscopy
Keywords: stars: abundances - stars: emission-line, Be -
fundamental parameters - supergiants - stars: AGB, post-AGB -
stars: supergiants - Galaxy: centre
Abstract:
As part of a programme to investigate spatial variations in the
Galactic chemical composition, we have been searching for normal
B-type stars and A-type supergiants near the Galactic center. During
this search we have found eleven peculiar stars, and in some cases
performed detailed abundance analyses of them which suggest that they
may be at a post-AGB evolutionary stage. The A-type post-AGB
candidates show [Fe/H]=-1.0 to -2.0, and [O/Fe]~+1.4, typical of the
post-AGB abundance patterns discussed in the literature. One star, LS
3591 (=SAO 243756), has also been examined recently by Oudmaijer
(1996A&A...306..823O 1996A&A...306..823O); its spectrum appears to be changing very
rapidly, which may indicate erratic mass loss or the incipient
formation of a planetary nebula. A B-type post-AGB candidate, LS 4950,
has a similar spectrum to a well studied post-AGB star, LSIV -12 111.
However, an examination of the line strengths and elemental abundances
of LS 4950 show that it is peculiar for both a PopulationII, post-AGB,
B-type star and for a normal, PopulationI, B-type supergiant. Two
other B-type stars, LS 4825 and LS 5112, are either post-AGB stars
near the Galactic center or normal B-type supergiants lying well
beyond the Galactic center. In addition, several Be-type stars have
been newly (or more clearly) identified from our spectra.
Objects:
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RA (2000) DE Designation(s)
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16 25 02.5 -60 03 32 LS 3591
16 24 39.3 -54 38 08 LS 3593
18 21 47.0 -29 45 07 LS 4950
17 17 07.4 -24 45 40 LS 4039
18 16 00.4 -30 45 46 LS 4825
18 40 48.4 -17 04 36 LS 5112
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
appena.dat 42 86 *Spectral line data for two post-AGB A-type stars
appenb.dat 38 56 *Spectral line data for four B-type stars towards
the Galactic Center
appen.tex 65 276 LaTeX version of the tables
appen.ps 72 440 PostScript version of the tables
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Note on appena.dat: appena.dat correspond to tables 12 and 13
Note on appenb.dat: appenb.dat correspond to tables 14 and 15
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See also:
VI/72 : Atomic Transition Probabilities, Sc-Ni (NIST 1993)
Byte-by-byte Description of file: appena.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Ion
7- 13 F7.2 0.1nm lambda Wavelength
15- 17 I3 --- RMT Multiplet number
19- 23 F5.2 eV chi Excitation potential
25- 29 F5.2 --- loggf log of oscillator strength
31- 33 I3 0.1nm EWLS3591 ? Equivalent width for the star LS 3591
34 A1 --- u_EWLS3591 Uncertainty flag on EWLS3591
36- 38 I3 0.1nm EWLS3593 ? Equivalent width for the star LS 3593
40- 42 A3 --- r_loggf Reference for the oscillator strength (1)
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Note (1): References for the atomic data.
fmw = Fuhr, Martin & Wiese 1988, Cat. VI/72,
J. Phys. Chem. Ref. Data 17, Suppl.4.
nk = Kurucz 1990, Trans IAV B, 20, 168 (magnetic tape)
ob = O'Brien et al. 1991, J. Opt. Soc. Am. B, 8, 1185
op = Opacity Project (O I, Hibbert et al. 1991, J. Phys B, 24, 3943)
zhu = Zhu et al. 1989, Phys Rev A., 40, 3721
wm = Wiese & Martin 1980, NSRDS-NBS 68
wsm = Wiese, Smith, & Martin 1969, NSRDS-NBS 22
sl = Sigut & Landstreet, 1990MNRAS.247..611S 1990MNRAS.247..611S
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Byte-by-byte Description of file: appenb.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Ion Ion (1)
8- 14 F7.2 0.1nm lambda Wavelength
15 A1 --- --- [,] Separation comma
16- 22 F7.2 0.1nm lambda2 ? Second wavelength (2)
24- 26 I3 0.1nm EWLS4950 ? Equivalent width for the star LS 4950
28- 30 I3 0.1nm EWLS4039 ? Equivalent width for the star LS 4039
32- 34 I3 0.1nm EWLS4825 ? Equivalent width for the star LS 4825
36- 38 I3 0.1nm EWLS5112 ? Equivalent width for the star LS 5112
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Note (1): All atomic data has been taken from the compilation by S. Jeffrey 1991
Newsletter on the Analysis of Astronomical Spectra, No. 16, p. 17.
Note (2): Where two lines are listed together, they represent an unresolved
blend (only blends of the same species are included).
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Acknowledgements: Kim A Venn
(End) Patricia Bauer [CDS] 23-Mar-1998