dc.contributor.author |
Garcia-Hernandez, D. A |
|
dc.contributor.author |
Lambert, D. L |
|
dc.contributor.author |
Kameswara Rao, N |
|
dc.contributor.author |
Hinkle, K. H |
|
dc.contributor.author |
Eriksson, K |
|
dc.date.accessioned |
2010-04-16T10:57:02Z |
|
dc.date.available |
2010-04-16T10:57:02Z |
|
dc.date.issued |
2010-05 |
|
dc.identifier.citation |
The Astrophysical Journal, Vol. 714, No. 1, pp. 144 - 154 |
en |
dc.identifier.issn |
0004-637X |
|
dc.identifier.uri |
http://hdl.handle.net/2248/5099 |
|
dc.description |
Open Access |
|
dc.description.abstract |
We investigate the relationship between R Coronae Borealis (RCB) stars and hydrogen-deficient carbon (HdC) stars by measuring precise 16O/18O ratios for five cool RCB stars. The 16O/18O ratios are derived by spectrum synthesis from high-resolution (R ~ 50, 000) K-band spectra. Lower limits to the 16O/17O and 14N/15N ratios as well as Na and S abundances (when possible) are also given. RCB stars in our sample generally display less 18O than HdC stars—the derived 16O/18O ratios range from 3 to 20. The only exception is the RCB star WX CrA, which seems to be an HdC-like star with 16O/18O = 0.3. Our result of a higher 16O/18O ratio for the RCB stars must be accounted for by a theory of the formation and evolution of HdC and RCB stars. We speculate that a late dredge-up of products of He burning, principally 12C and 16O, may convert an 18O-rich HdC star into an 18O-poor RCB star as the H-deficient star begins its final evolution from a cool supergiant to the top of the white dwarf cooling track. |
en |
dc.language.iso |
en |
en |
dc.publisher |
Institute of Physics |
en |
dc.relation.uri |
http://iopscience.iop.org/0004-637X/714/1/144/ |
en |
dc.rights |
© Institute of Physics |
en |
dc.subject |
Infrared: Stars |
en |
dc.subject |
Stars: Abundances |
en |
dc.subject |
Stars: Atmospheres |
en |
dc.subject |
Stars: Chemically Peculiar |
en |
dc.subject |
White Dwarfs |
en |
dc.title |
Oxygen isotopic ratios in cool R coronae borealis stars |
en |
dc.type |
Article |
en |