Table · dataset · 1997
C isotopic ratio in N- and SC-type stars
Listed in IVOA Registry (Virtual Observatory)
We present a result of quantitative analysis of ^12^C/^13^C ratios in 62 N-type and 15 SC-type carbon stars.
Description
By the use of CCD as a detector we can obtain spectra of resolution ~20,000 with enough signal-to-noise ratios for a large number of carbon stars, for which ^12^C/^13^C ratios have not yet been derived. Carbon isotopic ratios are determined from lines of the CN red system around 8000A, based on the iso-intensity method and line-blanketed model atmospheres.
The average of ^12^C/^13^C ratios in 62 N-type carbon stars is found to be 27+/-11 (standard deviation). The majority of the N-type carbon stars studied (about 85%) are found to have ^12^C/^13^C ratios less than 40, and the number of stars which have ^12^C/^13^C ratios larger than 40 is found to be relatively small. This result shows a marked contrast to some of the previous results that have shown the opposite distribution, namely, ^12^C/^13^C ratios mostly larger than 40 in N-type carbon stars.
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The average of ^12^C/^13^C ratios in 15 SC-type carbon stars is found to be 22+/-14 (standard deviation). Most of the SC-type carbon stars studied are found to have ^12^C/^13^C ratios larger than 10, while only three of them turn out to be ^13^C-rich. This is in contrast with the earlier classification based on low resolution spectra which classified them as J-type, that is, ^13^C-rich.
The earlier temperature scale which classified SC-type carbon stars as the latest (C8-9) based on their strong NaI D lines can not be necessarily justified. The strong NaI D lines of SC stars should be attributed to the peculiar atmospheric structure due to C/O ratios very near to unity. The resulting ^12^C/^13^C ratios are partly consistent with the scenario in which M giants evolve through SC-type to N-type carbon stars, as ^12^C produced during the helium shell flash is added to the envelope.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/310/933 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 1996A&A...310..933O ui.adsabs.harvard.edu/abs/1996A%26A...310..933O ↗
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/310/933 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Optical
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Astronomical sciences 73%
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/310/933 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:group:5101 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (73%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:optical | source · 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 |