GRACES observations of young [α/Fe]-rich stars
-
Altmetric Citations
Yong, David; Casagrande, Luca; Venn, Kim; Chene, Andre-Nicolas; Keown, Jared; Malo, Lison; Martioli, Eder; Alves-Brito, Alan; Asplund, Martin; Dotter, Aaron; Martell, Sarah L.; Melendez, Jorge; Schlesinger, Katharine J.
Description
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...[Show more]
dc.contributor.author | Yong, David | |
---|---|---|
dc.contributor.author | Casagrande, Luca | |
dc.contributor.author | Venn, Kim | |
dc.contributor.author | Chene, Andre-Nicolas | |
dc.contributor.author | Keown, Jared | |
dc.contributor.author | Malo, Lison | |
dc.contributor.author | Martioli, Eder | |
dc.contributor.author | Alves-Brito, Alan | |
dc.contributor.author | Asplund, Martin | |
dc.contributor.author | Dotter, Aaron | |
dc.contributor.author | Martell, Sarah L. | |
dc.contributor.author | Melendez, Jorge | |
dc.contributor.author | Schlesinger, Katharine J. | |
dc.date.accessioned | 2017-01-09T00:45:09Z | |
dc.date.available | 2017-01-09T00:45:09Z | |
dc.identifier.issn | 0035-8711 | |
dc.identifier.uri | http://hdl.handle.net/1885/111559 | |
dc.description.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 straggler origin. | |
dc.description.sponsorship | This work is based on observations obtained with ESPaDOnS, located at the Canada-France-Hawaii Telescope (CFHT). CFHT is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientique of France, and the University of Hawai'i. ESPaDOnS is a collaborative project funded by France (CNRS, MENESR, OMP, LATT), Canada (NSERC), CFHT, and ESA. ESPaDOnS was remotely controlled from the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovaç ao (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). We thank the anonymous referee for helpful comments. DY thanks John E. Norris for helpful discussions. DY, LC, MA, AD, and KS gratefully acknowledge support from the Australian Research Council (grants FL110100012, DP120100991, FT140100554, and DP150100250). SMgratefully acknowledges support from the Australian Research Council (grant DE 140100598). JMthanks support by FAPESP (2010/50930-6). | |
dc.format.mimetype | application/pdf | |
dc.publisher | Oxford University Press | |
dc.rights | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. http://www.sherpa.ac.uk/romeo/issn/0035-8711/..."author can archive publisher's version/PDF" from SHERPA/RoMEO site (as at 9/01/17). | |
dc.source | Monthly Notices of the Royal Astronomical Society | |
dc.title | GRACES observations of young [α/Fe]-rich stars | |
dc.type | Journal article | |
local.identifier.citationvolume | 459 | |
dc.date.issued | 2016-03-23 | |
local.identifier.ariespublication | u4571891xPUB37 | |
local.publisher.url | http://www.oxfordjournals.org/en/ | |
local.type.status | Published Version | |
local.contributor.affiliation | Yong, D., Research School of Astronomy and Astrophysics, The Australian National University | |
local.contributor.affiliation | Casagrande, L., Research School of Astronomy and Astrophysics, The Australian National University | |
local.contributor.affiliation | Asplund, M., Research School of Astronomy and Astrophysics, The Australian National University | |
local.contributor.affiliation | Dotter, A., Research School of Astronomy and Astrophysics, The Australian National University | |
local.contributor.affiliation | Schlesinger, K. J., Research School of Astronomy and Astrophysics, The Australian National University | |
dc.relation | http://purl.org/au-research/grants/arc/FL110100012 | |
dc.relation | http://purl.org/au-research/grants/arc/DP120100991 | |
dc.relation | http://purl.org/au-research/grants/arc/FT140100554 | |
dc.relation | http://purl.org/au-research/grants/arc/DP150100250 | |
dc.relation | http://purl.org/au-research/grants/arc/DE140100598 | |
local.bibliographicCitation.issue | 1 | |
local.bibliographicCitation.startpage | 487 | |
local.bibliographicCitation.lastpage | 495 | |
local.identifier.doi | 10.1093/mnras/stw676 | |
dcterms.accessRights | Open Access | |
Collections | ANU Research Publications |
Download
File | Description | Size | Format | Image |
---|---|---|---|---|
01_Yong_GRACES_Observations_2016.pdf | 963.55 kB | Adobe PDF |
Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.
Updated: 17 November 2022/ Responsible Officer: University Librarian/ Page Contact: Library Systems & Web Coordinator