Asteroseismic analysis of eight solar-like oscillating evolved stars in the open cluster NGC 6811

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Author: Orhan, Zeynep Celik
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford Univ Press 2021
• Subjects: stars: evolution; stars: fundamental parameters; stars: interiors; stars: oscillations; Minimum Delta-Nu; Red Giants; Fundamental Properties; Model Computations; Host Stars; Mass; Constraints; Frequencies; Amplitudes; Evolution; Ege; sami
• Online Access: https://hdl.handle.net/11454/77339; https://doi.org/10.1093/mnras/stab2031

The Kepler space telescope has provided exquisite data with which to perform asteroseismic analysis on evolved star ensembles. Studying star clusters offers significant insight into stellar evolution and structure, due to having a large number of stars with essentially the same age, distance, and chemical composition. This study analysed eight solar-like oscillating evolved stars that are members of the open cluster NGC 6811 and modelled them for the first time. The fundamental stellar parameters are obtained from the interior model using observational asteroseismic and non-asteroseismic constraints. The stellar interior models are constructed using the MESA evolution code. The mass-loss method is included in the interior models of the stars. The stellar masses and radius ranges of the stars are 2.23-2.40M(circle dot) and 8.47-12.38 R (circle dot), respectively. Typical uncertainties for the mass and radius are similar to 0.11M(circle dot) and similar to 0.09 R-circle dot, respectively. The model masses and radii are compared with masses and radii obtained from asteroseismic and non-asteroseismic methods (scaling relations and classic methods). The stellar ages fell in the range between 0.71 and 0.82 Gyr, with a typical uncertainty of similar to 18 per cent. The model ages of the stars calculated in this study are compatible with those reported in the literature for NGC 6811. Scientific and Technological Research Council of Turkey [TUBITAK:118F352] I thank Dr Mutlu Yildiz for sharing his invaluable experience and contributing to this study with Gaia database analysis, and Sibel Ortel, who has been a great help in the modelling process. I am grateful to Ege University Planning and Monitoring Coordination of Organizational Development and Directorate of Library and Documentation for their support in editing and proofreading this study. I also thank my son Emirhan Sami and my husband Mustafa Orhan for their support. This work is supported by the Scientific and Technological Research Council of Turkey ...