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Title: Asteroseismic study on cluster distance moduli for red giant branch stars in NGC 6791 and NGC 6819

Abstract

Stellar distance is an important basic parameter in stellar astrophysics. Stars in a cluster are thought to be formed coevally from the same interstellar cloud of gas and dust; therefore, they are expected to have common properties. These common properties strengthen our ability to constrain theoretical models and/or to determine fundamental parameters, such as stellar mass, metal fraction, and distance, when tested against an ensemble of cluster stars. Here we derive a new relation based on solar-like oscillations, photometric observations, and the theory of stellar structure and evolution of red giant branch stars to determine cluster distance moduli through the global oscillation parameters Δν and ν{sub max} and photometric data V. The values of Δν and ν{sub max} are derived from Kepler observations. At the same time, it is used to interpret the trends between V and Δν. From the analyses of this newly derived relation and observational data of NGC 6791 and NGC 6819, we devise a method in which all stars in a cluster are regarded as one entity to determine the cluster distance modulus. This approach fully reflects the characteristic of member stars in a cluster as a natural sample. From this method we derive true distancemore » moduli of 13.09 ± 0.10 mag for NGC 6791 and 11.88 ± 0.14 mag for NGC 6819. Additionally, we find that the distance modulus only slightly depends on the metallicity [Fe/H] in the new relation. A change of 0.1 dex in [Fe/H] will lead to a change of 0.06 mag in the distance modulus.« less

Authors:
;  [1]
  1. Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)
Publication Date:
OSTI Identifier:
22357043
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 786; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; DISTANCE; DUSTS; EVOLUTION; INTERSTELLAR SPACE; MASS; METALLICITY; OSCILLATIONS; RED GIANT STARS; STAR CLUSTERS; STARS

Citation Formats

Wu, T., Li, Y., and Hekker, S., E-mail: wutao@ynao.ac.cn, E-mail: ly@ynao.ac.cn, E-mail: hekker@mps.mpg.de. Asteroseismic study on cluster distance moduli for red giant branch stars in NGC 6791 and NGC 6819. United States: N. p., 2014. Web. doi:10.1088/0004-637X/786/1/10.
Wu, T., Li, Y., & Hekker, S., E-mail: wutao@ynao.ac.cn, E-mail: ly@ynao.ac.cn, E-mail: hekker@mps.mpg.de. Asteroseismic study on cluster distance moduli for red giant branch stars in NGC 6791 and NGC 6819. United States. https://doi.org/10.1088/0004-637X/786/1/10
Wu, T., Li, Y., and Hekker, S., E-mail: wutao@ynao.ac.cn, E-mail: ly@ynao.ac.cn, E-mail: hekker@mps.mpg.de. 2014. "Asteroseismic study on cluster distance moduli for red giant branch stars in NGC 6791 and NGC 6819". United States. https://doi.org/10.1088/0004-637X/786/1/10.
@article{osti_22357043,
title = {Asteroseismic study on cluster distance moduli for red giant branch stars in NGC 6791 and NGC 6819},
author = {Wu, T. and Li, Y. and Hekker, S., E-mail: wutao@ynao.ac.cn, E-mail: ly@ynao.ac.cn, E-mail: hekker@mps.mpg.de},
abstractNote = {Stellar distance is an important basic parameter in stellar astrophysics. Stars in a cluster are thought to be formed coevally from the same interstellar cloud of gas and dust; therefore, they are expected to have common properties. These common properties strengthen our ability to constrain theoretical models and/or to determine fundamental parameters, such as stellar mass, metal fraction, and distance, when tested against an ensemble of cluster stars. Here we derive a new relation based on solar-like oscillations, photometric observations, and the theory of stellar structure and evolution of red giant branch stars to determine cluster distance moduli through the global oscillation parameters Δν and ν{sub max} and photometric data V. The values of Δν and ν{sub max} are derived from Kepler observations. At the same time, it is used to interpret the trends between V and Δν. From the analyses of this newly derived relation and observational data of NGC 6791 and NGC 6819, we devise a method in which all stars in a cluster are regarded as one entity to determine the cluster distance modulus. This approach fully reflects the characteristic of member stars in a cluster as a natural sample. From this method we derive true distance moduli of 13.09 ± 0.10 mag for NGC 6791 and 11.88 ± 0.14 mag for NGC 6819. Additionally, we find that the distance modulus only slightly depends on the metallicity [Fe/H] in the new relation. A change of 0.1 dex in [Fe/H] will lead to a change of 0.06 mag in the distance modulus.},
doi = {10.1088/0004-637X/786/1/10},
url = {https://www.osti.gov/biblio/22357043}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 786,
place = {United States},
year = {Thu May 01 00:00:00 EDT 2014},
month = {Thu May 01 00:00:00 EDT 2014}
}