On the AGB stars of M4: A robust disagreement between spectroscopic observations and theory
dc.contributor.author | MacLean, B. T. | |
dc.contributor.author | Campbell, Simon W | |
dc.contributor.author | Amarsi, Anish M | |
dc.contributor.author | Nordlander, Thomas | |
dc.contributor.author | Cottrell, P L | |
dc.contributor.author | De Silva, Gayandhi | |
dc.contributor.author | Lattanzio, John | |
dc.contributor.author | Constantino, Thomas N | |
dc.contributor.author | D’Orazi, V | |
dc.contributor.author | Casagrande, Luca | |
dc.date.accessioned | 2019-12-20T02:21:09Z | |
dc.date.available | 2019-12-20T02:21:09Z | |
dc.date.issued | 2018 | |
dc.date.updated | 2019-08-04T08:20:22Z | |
dc.description.abstract | Several recent spectroscopic investigations have presented conflicting results on the existence of Na-rich asymptotic giant branch (AGB) stars in the Galactic globular cluster M4 (NGC 6121). The studies disagree on whether or not Na-rich red giant branch (RGB) stars evolve to the AGB. For a sample of previously published HERMES/AAT AGB and RGB stellar spectra, we present a re-analysis of O, Na, and Fe abundances, and a new analysis of Mg and Al abundances; we also present CN band strengths for this sample, derived from low-resolution AAOmega spectra. Following a detailed literature comparison, we find that the AGB samples of all studies consistently show lower abundances of Na and Al, and are weaker in CN, than RGB stars in the cluster. This is similar to recent observations of AGB stars in NGC6752 and M62. In an attempt to explain this result, we present new theoretical stellar evolutionary models for M4; however, these predict that all stars, including Na-rich RGB stars, evolve on to the AGB. We test the robustness of our abundance results using a variety of atmospheric models and spectroscopic methods; however, we do not find evidence that systematic modelling uncertainties can explain the apparent lack of Na-rich AGB stars in M4. We conclude that an unexplained, but robust, discordance between observations and theory remains for the AGB stars in M4. | en_AU |
dc.description.sponsorship | Based in part on data acquired through the AAO, via programs 09B/15, 14B/27, and 15A/21 (PI: Campbell); some of these observations were conducted by Elizabeth Wylie de Boer, Richard Stancliffe, and George Angelou. Part of this work was supported by the DAAD (PPP project 57219117) with funds from the German Federal Ministry of Education and Research (BMBF). Parts of this research were conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. BTM acknowledges the financial support of the Research Training Program (RTP) scheme scholarship. SWC acknowledges federal funding from the Australian Research Council though the Future Fellowship grant entitled ‘Where are the Convective Boundaries in Stars?’ (FT160100046). AMA acknowledges funds from the Alexander von Humboldt Foundation in the framework of the Sofja Kovalevskaja Award endowed by the Federal Ministry of Education and Research. TN acknowledges funding from the Australian Research Council (grant DP150100250). VD acknowledges support from the AAO distinguished visitor programme 2016. LC gratefully acknowledges support from the Australian Research Council (grants DP150100250, FT160100402). This work was supported by computational resources provided by the Australian Government through the National Computational Infrastructure (NCI) under the National Computational Merit Allocation Scheme (project ew6). | en_AU |
dc.format.mimetype | application/pdf | en_AU |
dc.identifier.issn | 0035-8711 | en_AU |
dc.identifier.uri | http://hdl.handle.net/1885/196424 | |
dc.language.iso | en_AU | en_AU |
dc.provenance | http://sherpa.ac.uk/romeo/issn/0035-8711/..."author can archive publisher's version/PDF" from SHERPA/RoMEO site (as at 20/12/19). This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. | en_AU |
dc.publisher | Oxford University Press | en_AU |
dc.relation | http://purl.org/au-research/grants/arc/CE170100013 | en_AU |
dc.relation | http://purl.org/au-research/grants/arc/FT160100046 | en_AU |
dc.relation | http://purl.org/au-research/grants/arc/FT160100402 | en_AU |
dc.relation | http://purl.org/au-research/grants/arc/DP150100250 | en_AU |
dc.rights | © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society | en_AU |
dc.source | Monthly Notices of the Royal Astronomical Society | en_AU |
dc.title | On the AGB stars of M4: A robust disagreement between spectroscopic observations and theory | en_AU |
dc.type | Journal article | en_AU |
dcterms.accessRights | Open Access | en_AU |
local.bibliographicCitation.issue | 1 | en_AU |
local.bibliographicCitation.lastpage | 395 | en_AU |
local.bibliographicCitation.startpage | 373 | en_AU |
local.contributor.affiliation | MacLean, B. T., Monash University | en_AU |
local.contributor.affiliation | Campbell, Simon W, Monash University | en_AU |
local.contributor.affiliation | Amarsi, Anish M, Max Planck Institute for Astronomy | en_AU |
local.contributor.affiliation | Nordlander, Thomas, College of Science, ANU | en_AU |
local.contributor.affiliation | Cottrell, P L, University of Canterbury | en_AU |
local.contributor.affiliation | De Silva, Gayandhi, Australian Astronomical Observatory | en_AU |
local.contributor.affiliation | Lattanzio, John, Monash University | en_AU |
local.contributor.affiliation | Constantino, Thomas N, Monash University | en_AU |
local.contributor.affiliation | D’Orazi , V, Macquarie University | en_AU |
local.contributor.affiliation | Casagrande, Luca, College of Science, ANU | en_AU |
local.contributor.authoremail | u5209059@anu.edu.au | en_AU |
local.contributor.authoruid | Nordlander, Thomas, u1019177 | en_AU |
local.contributor.authoruid | Casagrande, Luca, u5209059 | en_AU |
local.description.notes | Imported from ARIES | en_AU |
local.identifier.absfor | 020104 - Galactic Astronomy | en_AU |
local.identifier.absfor | 020110 - Stellar Astronomy and Planetary Systems | en_AU |
local.identifier.absseo | 970102 - Expanding Knowledge in the Physical Sciences | en_AU |
local.identifier.ariespublication | u4485658xPUB2593 | en_AU |
local.identifier.citationvolume | 481 | en_AU |
local.identifier.doi | 10.1093/mnras/sty2297 | en_AU |
local.identifier.scopusID | 2-s2.0-85054079651 | |
local.identifier.uidSubmittedBy | u4485658 | en_AU |
local.publisher.url | https://academic.oup.com/ | en_AU |
local.type.status | Published Version | en_AU |
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