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J/ApJS/120/113 Faint Emission Lines and Temperature (Esteban+ 1999)
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Faint Emission Lines and Temperature Fluctuations in M8
Esteban C., Peimbert M., Torres-Peimbert S., Garcia-Rojas J., Rodriguez M.
<Astrophys. J. Suppl. Ser. 120, 113 (1999)>
=1999ApJS..120..113E
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ADC_Keywords: Abundances; H II regions; Spectroscopy
Keywords: H II regions - ISM: abundances - ISM: individual (M8) - line:
identification
Abstract:
We present echelle spectroscopy in the 3500-10300{AA} range of the
Hourglass Nebula, which is embedded in the Galactic H II region M8.
The data were obtained using the 2.1m telescope at Observatorio
Astronomico Nacional in San Pedro Mqrtir, Baja California. We have
measured the intensities of 274 emission lines, in particular 88
permitted lines of C^+^, N^0^, N^+^, O^0^, O^+^, Ne^0^, S^0^, S^+^,
Si^0^, Si^+^, and Si^++^, some of them produced by recombination only
and others mainly by fluorescence. We have determined electron
temperatures and densities using different line intensity ratios. We
derive the He^+^, C^++^, O^+^, and O^++^ ionic abundances as well
as - for the first time in a nebular object - the total O abundance
from recombination lines; these nebular values are independent of the
temperature structure of the nebula. We have also derived abundances
from collisionally excited lines for a large number of ions and
elements; these abundances do depend on the temperature structure.
Accurate t^2^ values have been derived by comparing the C^++^, O^+^,
and O^++^ ionic abundances obtained making use of both collisionally
excited lines and recombination lines. A comparison of the solar,
Orion Nebula, and M8 chemical abundances is made.
Objects: M8
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RA (2000) DE Designation(s)
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18 03 37 -24 23.2 NGC 6523 = Lagoon nebula
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 71 273 Emission line spectrum of M8
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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- 8 F8.2 0.1nm LabWave ? Wavelength observed in laboratory
11 A1 --- Note *Line footnote
17- 24 A8 --- Ion Ion Identification
26- 35 A10 --- Multiplet Ion multiplet name or number
38- 45 F8.2 0.1nm ObsWave ? Wavelength observed in spectrum
49- 55 F7.3 --- RelInten ? Line intensity relative to H{beta}
57 A1 --- u_RelInten uncertain line intensity relative to H{beta}
60- 66 F7.3 --- RelIntCor ? Reddening-corrected line intensity relative
to H{beta}
68 A1 --- u_RelIntCor uncertain reddening-corrected line intensity
relative to H{beta}
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Note on Note:
a: Possibly blended with an unidentified line.
b: Dubious identification.
c: Possibly affected by sky emission.
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History:
From ApJ electronic edition
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(End) Greg Schwarz (AAS) 25-Jan-2000