Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (32) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (49)
· Associated Articles
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Stellar oxygen abundances. 4: Systematic effects on oxygen abundances derived from the 6300 A (O I) and 7774 A O I lines
Authors:
King, Jeremy R.; Boesgaard, Ann Merchant
Affiliation:
AA(University of Hawaii, Honolulu, HI, US), AB(University of Hawaii, Honolulu, HI, US)
Publication:
The Astronomical Journal (ISSN 0004-6256), vol. 109, no. 1669, p. 383-395 (AJ Homepage)
Publication Date:
01/1995
Category:
Astronomy
Origin:
STI
NASA/STI Keywords:
ABUNDANCE, OXYGEN, OXYGEN SPECTRA, STELLAR ATMOSPHERES, DWARF STARS, INFRARED SPECTRA, LOCAL THERMODYNAMIC EQUILIBRIUM, METALLICITY, VISIBLE SPECTRUM
DOI:
10.1086/117283
Bibliographic Code:
1995AJ....109..383K

Abstract

We consider potential systematic effects on oxygen abundances derived from the 6300 A (OI) line and the 7774 A OI triplet. Our solar intensity spectra of the 7774 A triplet confirm previous results which indicate a discrepancy between the observed equivalent widths of Altrock (1968) and the values predicted by Local Thermodynamic Equilibrium (LTE) and recent NLTE models. However, this disagreement (at low micron(s)) does not seem to affect the solar O abundance as derived from flux spectra. We derive O abundances for a selection of relatively metal-rich F and G dwarfs from both the 6300 A (OI) line and 7774 A OI triplet and detail the various uncertainties which enter into the analyses. Minimizing possible systematic effects to the extent possible, we find for Teff approximately less than 6200-6300 K no systematic difference between the 6300 and 7774 A abundances. For Teff approximately greater than 6200-6300 K, however 7774 A abundances are substantially larger than the 6300 A abundances. This agreement in O abundances from the two features at cooler Teff conflicts with that of others and we suggest that the discrepancy may be due to the different model atmospheres utilized. If recently proposed, hotter Teff values for metal-poor dwarfs are correct, then there appears to be no discrepancy between the 6300 A abundances of metal-poor giants are correct, then there appears to be no discrepancy between the 6300 A abundances of metal-poor giants or dwarfs and the 7774 A abundances for dwarfs. This would seem to rule out substantial LTE departures or atmospheric inhomogeneity effects skewing metal-poor O abundances from the 7774 A triplet (for cooler stars having low metallicity anyway). Given the repeated inability of authors to reproduce each others' O abundances from the 6300 A (OI) line and the uncertainties in the solar equivalent width, we question the usual assumption that the 6300 A (OI) line and the uncertainties in the solar equivalent width, we question the usual assumption that the 6300 A (OI) abundances are more reliable than those from the permitted triplet.

Associated Articles

Part 1     Part  2     Part  3     Part  4     Part  5    

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences


More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints