Table · dataset · 2017
Reduced spectra of NGC 6528 stars
Listed in IVOA Registry (Virtual Observatory)
Here we explore robust ways of determining the iron content of metal-rich giant stars.
Description
We aim to understand what biases and shortcomings the widely applied methods suffer from. In this study we were mainly concerned with standard methods of analysing stellar spectra.
These include the analysis of individual lines to determine stellar parameters, and analysis of the broad wings of certain lines (e.g. Halpha and calcium lines) to determine effective temperature and surface gravity for the stars. For NGC 6528 we find that [Fe/H]=+0.04dex with a scatter of 0.07dex, which gives an error in the derived mean abundance of 0.02dex. Our work has two important conclusions for analysis of metal-rich red giant branch stars.
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Firstly, for spectra with S/N of below about 35 per reduced pixel, [Fe/H] becomes too high. Secondly, determination of Teff using the wings of the H{alpha} line results in [Fe/H] values about 0.1dex higher than if excitational equilibrium is used. The last conclusion is perhaps unsurprising, as we expect the NLTE effect to become more prominent in cooler stars and we can not use the the wings of the H{alpha} line to determine Teff for the cool stars in our sample.
We therefore recommend that in studies of metal-rich red giant stars care should be taken to obtain sufficient calibration data to enable use of the cooler stars.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/601/A31 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2017A&A...601A..31L ui.adsabs.harvard.edu/abs/2017A%26A...601A..31L ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/a%2Ba/601/a31 ↗
catalogue entry · from IVOA Registry
Topics
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Stellar astronomy and planetary systems 76%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/601/a31 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:field:510109 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (76%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |