J/ApJ/659/1265 Emission lines in 4 planetary nebulae (Sharpee+, 2007)
s-Process abundances in planetary nebulae.
Sharpee B., Zhang Y., Williams R., Pellegrini E., Cavagnolo K.,
Baldwin J.A., Phillips M., Liu X.-W.
<Astrophys. J., 659, 1265-1290 (2007)>
=2007ApJ...659.1265S 2007ApJ...659.1265S
ADC_Keywords: Planetary nebulae ; Abundances
Keywords: ISM: abundances - nuclear reactions, nucleosynthesis, abundances -
planetary nebulae: general
Abstract:
The s-process should occur in all but the lower mass progenitor stars
of planetary nebulae, and this should be reflected in the chemical
composition of the gas that is expelled to create the current
planetary nebula shell. Weak forbidden emission lines are expected
from several s-process elements in these shells and have been searched
for and in some cases detected in previous investigations. Here we
extend these studies by combining very high signal-to-noise ratio
echelle spectra of a sample of PNe with a critical analysis of the
identification of the emission lines of Z>30 ions. Emission lines of
Br, Kr, Xe, Rb, Ba, and Pb are detected with a reasonable degree of
certainty in at least some of the objects studied here, and we also
tentatively identify lines from Te and I, each in one object. The
strengths of these lines indicate enhancement of s-process elements in
the central star progenitors, and we determine the abundances of Br,
Kr, and Xe, elements for which atomic data relevant for abundance
determination have recently become available. As representative
elements of the "light" and "heavy" s-process peaks, Kr and Xe exhibit
similar enhancements over solar values, suggesting that PN progenitors
experience substantial neutron exposure.
Description:
We obtained spectra of the PNe IC 2501, IC 4191, and NGC 2440 during
two observing runs of two nights each in early 2003 using the Las
Campanas Observatory (LCO) Baade 6.5m telescope with the MIKE echelle
spectrograph.
NGC 7027 was observed on four nights in 2002 June with the Mayall 4m
Telescope at Kitt Peak National Observatory (KPNO) using the
Cassegrain echelle spectrograph.
Objects:
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RA (2000) DE Designation(s)
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09 38 47.2 -60 05 31 IC 2501 = PN G281.0-05.6
13 08 47.3 -67 38 38 IC 4191 = PN G304.5-04.8
07 41 54.9 -18 12 30 NGC 2440 = PN G234.8+02.4
21 07 01.6 +42 14 10 NGC 7027 = PN G084.9-03.4
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 79 3087 Emission-Line identifications and intensities
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See also:
V/84 : Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker+, 1992)
Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- PN PN name
10- 17 F8.2 0.1nm lambda Observed wavelength
19- 24 F6.2 km/s FWHM Line FWHM
26- 34 F9.4 ---- Flux Flux normalized to Hbeta=100
36- 44 F9.4 ---- Int Integrated flux normalized to Hbeta=100
46- 52 F7.1 --- S/N Signal-to-noise ration
55- 65 A11 --- Line Line identification
66- 74 F9.2 0.1nm lambdaL ? Line Wavelength
76- 79 A4 --- Notes Notes (1)
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Note (1): Notes as follows:
: = uncertain identification
? = uncertain feature
bl = line blend
ns = blend with night-sky line
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Jan-2009