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GRACES observations of young [ α / Fe ]-rich stars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Yong, David Casagrande, Luca Venn, Kim A. Chene, Andre Nicolas Keown, Jared Malo, L. Román Martioli, Eder Alves-Brito, Alan Asplund, M. S. Fredrik Dotter, Aaron L. Martell, Sarah L. Melendez, Jesus Schlesinger, Katharine J. |
| Copyright Year | 2016 |
| Abstract | We measure chemical abundance ratios and radial velocities in four massive (i.e. young) [α/Fe]-rich red giant stars using high-resolution high-S/N spectra from ESPaDOnS fed by Gemini-GRACES. Our differential analysis ensures that our chemical abundances are on the same scale as the Alves-Brito et al. (2010) study of bulge, thin, and thick disc red giants. We confirm that the program stars have enhanced [α/Fe] ratios and are slightly metal poor. Aside from lithium enrichment in one object, the program stars exhibit no chemical abundance anomalies when compared to giant stars of similar metallicity throughout the Galaxy. This includes the elements Li, O, Si, Ca, Ti, Cr, Ni, Cu, Ba, La, and Eu. Therefore, there are no obvious chemical signatures that can help to reveal the origin of these unusual stars. While our new observations show that only one star (not the Li-rich object) exhibits a radial velocity variation, simulations indicate that we cannot exclude the possibility that all four could be binaries. In addition, we find that two (possibly three) stars show evidence for an infrared excess, indicative of a debris disc. This is consistent with these young [α/Fe]-rich stars being evolved blue stragglers, suggesting their apparent young age is a consequence of a merger or mass transfer. We would expect a binary fraction of ∼50 per cent or greater for the entire sample of these stars, but the signs of the circumbinary disc may have been lost since these features can have short time-scales. Radial velocity monitoring is needed to confirm the blue |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://openresearch-repository.anu.edu.au/bitstream/1885/111559/1/01_Yong_GRACES_Observations_2016.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | ABRA gene Antivirus software Binary file Binary number Chromium Earth bulge Ehrlich units per deciliter Exhibits as Topic Field electron emission GUCY2C protein, human Gene Ontology Term Enrichment Gigantism Image resolution Iron Lactic acid Linear algebra Lithium Offset binary Pure Red-Cell Aplasia Radial (radio) Radial basis function Simulation Stars, Celestial Titanium Velocity (software development) |
| Content Type | Text |
| Resource Type | Article |
