Berkeley 51, a young open cluster with four yellow supergiants
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Title: | Berkeley 51, a young open cluster with four yellow supergiants |
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Authors: | Negueruela, Ignacio | Monguió, María | Marco, Amparo | Tabernero, Hugo M. | González-Fernández, Carlos | Dorda Laforet, Ricardo |
Research Group/s: | Astrofísica Estelar (AE) |
Center, Department or Service: | Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal |
Keywords: | Stars: evolution | Supergiants | Open clusters and associations: individual: Berkeley 51 |
Knowledge Area: | Astronomía y Astrofísica | Física Aplicada |
Issue Date: | 1-Jul-2018 |
Publisher: | Oxford University Press |
Citation: | Monthly Notices of the Royal Astronomical Society. 2018, 477(3): 2976-2990. doi:10.1093/mnras/sty718 |
Abstract: | The heavily obscured open cluster Berkeley 51 shows characteristics typical of young massive clusters, even though the few previous studies have suggested older ages. We combine optical (UBV) and 2MASS photometry of the cluster field with multi-object and long-slit optical spectroscopy for a large sample of stars. We apply classical photometric analysis techniques to determine the reddening to the cluster, and then derive cluster parameters via isochrone fitting. We find a large population of B-type stars, with a main-sequence turn-off at B3 V, as well as a large number of supergiants with spectral types ranging from F to M. We use intermediate-resolution spectra of the evolved cool stars to derive their stellar parameters and find an essentially solar iron abundance. Under the plausible assumption that our photometry reaches stars still close to the zero-age main sequence, the cluster is located at d ≈ 5.5 kpc and has an age of ∼60 Ma, though a slightly younger and more distant cluster cannot be ruled out. Despite the apparent good fit of isochrones, evolved stars seem to reside in positions of the colour–magnitude diagram far away from the locations where stellar tracks predict helium burning to occur. Of particular interest is the presence of four yellow supergiants, two on the ascending branch and two others close to or inside the instability strip. |
Sponsor: | This visit was funded by the Conselleria de Educación, Cultura y Deporte of the Generalitat Valenciana under grant BEST/2014/276. This research is partially supported by the Spanish Government Ministerio de Economía y Competitivad (MINECO/FEDER) under grant AYA2015-68012-C2-2-P. HMT acknowledges support from MINECO under fellowship FJCI-2014-23001. MM acknowledges the support of a research grant funded by the STFC (ST/M001008/1). |
URI: | http://hdl.handle.net/10045/76725 |
ISSN: | 0035-8711 (Print) | 1365-2966 (Online) |
DOI: | 10.1093/mnras/sty718 |
Language: | eng |
Type: | info:eu-repo/semantics/article |
Rights: | © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society |
Peer Review: | si |
Publisher version: | https://doi.org/10.1093/mnras/sty718 |
Appears in Collections: | INV - Astrofísica Estelar - Artículos de Revistas |
Files in This Item:
File | Description | Size | Format | |
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2018_Negueruela_etal_MNRAS.pdf | 4,43 MB | Adobe PDF | Open Preview | |
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