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Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members : III. Constraints from a subgiant

Brogaard, K. ; Grundahl, F. ; Sandquist, E. L. ; Slumstrup, D. ; Jensen, M. L. ; Thomsen, J. B. ; Jørgensen, J. H. ; Larsen, J. R. ; Bjørn, S. T. and Sørensen, C. T.G. , et al. (2021) In Astronomy and Astrophysics 649.
Abstract

Context. Models of stellar structure and evolution can be constrained using accurate measurements of the parameters of eclipsing binary members of open clusters. Multiple binary stars provide the means to tighten the constraints and, in turn, to improve the precision and accuracy of the age estimate of the host cluster. In the previous two papers of this series, we have demonstrated the use of measurements of multiple eclipsing binaries in the old open cluster NGC 6791 to set tighter constraints on the properties of stellar models than was previously possible, thereby improving both the accuracy and precision of the cluster age. Aims. We identify and measure the properties of a non-eclipsing cluster member, V56, in NGC 6791 and... (More)

Context. Models of stellar structure and evolution can be constrained using accurate measurements of the parameters of eclipsing binary members of open clusters. Multiple binary stars provide the means to tighten the constraints and, in turn, to improve the precision and accuracy of the age estimate of the host cluster. In the previous two papers of this series, we have demonstrated the use of measurements of multiple eclipsing binaries in the old open cluster NGC 6791 to set tighter constraints on the properties of stellar models than was previously possible, thereby improving both the accuracy and precision of the cluster age. Aims. We identify and measure the properties of a non-eclipsing cluster member, V56, in NGC 6791 and demonstrate how this provides additional model constraints that support and strengthen our previous findings. Methods. We analyse multi-epoch spectra of V56 from FLAMES in conjunction with the existing photometry and measurements of eclipsing binaries in NGC6971. Results. The parameters of the V56 components are found to be Mp = 1.103 ± 0.008 Mpdbl and Ms = 0.974 ± 0.007 Mpdbl, Rp = 1.764 ± 0.099 Rpdbl and Rs = 1.045 ± 0.057 Rpdbl, Teff,p = 5447 ± 125 K and Teff,s = 5552 ± 125 K, and surface [Fe/H] = +0.29 ± 0.06 assuming that they have the same abundance. Conclusions. The derived properties strengthen our previous best estimate of the cluster age of 8.3 ± 0.3 Gyr and the mass of stars on the lower red giant branch (RGB), which is MRGB = 1.15 ± 0.02 Mpdbl for NGC 6791. These numbers therefore continue to serve as verification points for other methods of age and mass measures, such as asteroseismology.

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publication status
published
subject
keywords
Binaries: spectroscopic, Open clusters and associations: individual: NGC6791, Stars: abundances, Stars: fundamental parameters, Stars: individual: V604 Lyr
in
Astronomy and Astrophysics
volume
649
article number
A178
pages
8 pages
publisher
EDP Sciences
external identifiers
  • scopus:85107424203
ISSN
0004-6361
DOI
10.1051/0004-6361/202140911
language
English
LU publication?
yes
id
443dd865-ce0e-46aa-850b-bbfee8e946f3
date added to LUP
2021-06-24 11:07:25
date last changed
2024-04-20 07:56:43
@article{443dd865-ce0e-46aa-850b-bbfee8e946f3,
  abstract     = {{<p>Context. Models of stellar structure and evolution can be constrained using accurate measurements of the parameters of eclipsing binary members of open clusters. Multiple binary stars provide the means to tighten the constraints and, in turn, to improve the precision and accuracy of the age estimate of the host cluster. In the previous two papers of this series, we have demonstrated the use of measurements of multiple eclipsing binaries in the old open cluster NGC 6791 to set tighter constraints on the properties of stellar models than was previously possible, thereby improving both the accuracy and precision of the cluster age. Aims. We identify and measure the properties of a non-eclipsing cluster member, V56, in NGC 6791 and demonstrate how this provides additional model constraints that support and strengthen our previous findings. Methods. We analyse multi-epoch spectra of V56 from FLAMES in conjunction with the existing photometry and measurements of eclipsing binaries in NGC6971. Results. The parameters of the V56 components are found to be Mp = 1.103 ± 0.008 Mpdbl and Ms = 0.974 ± 0.007 Mpdbl, Rp = 1.764 ± 0.099 Rpdbl and Rs = 1.045 ± 0.057 Rpdbl, Teff,p = 5447 ± 125 K and Teff,s = 5552 ± 125 K, and surface [Fe/H] = +0.29 ± 0.06 assuming that they have the same abundance. Conclusions. The derived properties strengthen our previous best estimate of the cluster age of 8.3 ± 0.3 Gyr and the mass of stars on the lower red giant branch (RGB), which is MRGB = 1.15 ± 0.02 Mpdbl for NGC 6791. These numbers therefore continue to serve as verification points for other methods of age and mass measures, such as asteroseismology. </p>}},
  author       = {{Brogaard, K. and Grundahl, F. and Sandquist, E. L. and Slumstrup, D. and Jensen, M. L. and Thomsen, J. B. and Jørgensen, J. H. and Larsen, J. R. and Bjørn, S. T. and Sørensen, C. T.G. and Bruntt, H. and Arentoft, T. and Frandsen, S. and Jessen-Hansen, J. and Orosz, J. A. and Mathieu, R. and Geller, A. and Ryde, N. and Stello, D. and Meibom, S. and Platais, I.}},
  issn         = {{0004-6361}},
  keywords     = {{Binaries: spectroscopic; Open clusters and associations: individual: NGC6791; Stars: abundances; Stars: fundamental parameters; Stars: individual: V604 Lyr}},
  language     = {{eng}},
  month        = {{05}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members : III. Constraints from a subgiant}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202140911}},
  doi          = {{10.1051/0004-6361/202140911}},
  volume       = {{649}},
  year         = {{2021}},
}