CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM
We have investigated the evolutionary status of 85 Peg within the framework of standard evolutionary theory. 85 Peg has been known to be a visual and spectroscopic binary system in the solar neighborhood. In spite of the accurate information of the total mass (~1.5M_⨀) and the distance (~12pc) fro...
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2007-03-01
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doaj-f51178ceb23c4400b0beb6bcff00b8322020-11-24T23:25:28ZengKorean Space Science Society (KSSS)Journal of Astronomy and Space Sciences2093-55872093-14092007-03-01241313810.5140/JASS.2007.24.1.031CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEMKiehunn Bach0Yong-Cheol Kim1Pierre Demarque2Department of Astronomy, Yonsei University, Seoul 120-749, KoreaDepartment of Astronomy, Yonsei University, Seoul 120-749, KoreaDepartment of Astronomy, Yale University, P.O.Box 2081001, New Haven CT06520-8101, USA We have investigated the evolutionary status of 85 Peg within the framework of standard evolutionary theory. 85 Peg has been known to be a visual and spectroscopic binary system in the solar neighborhood. In spite of the accurate information of the total mass (~1.5M_⨀) and the distance (~12pc) from the HIPPARCOS parallax, it has been undetermined an individual mass, therefore the evolved status of the system. Moreover, the coupled uncertainties of chemical composition and age, make matters worse in predicting an evolutionary status of the system. Nevertheless, we computed the various possible models for 85 Peg, and then calibrated stellar parameters by adjusting to the recent observational data. Our modelling computation has included recently updated input physics and stellar theory such as opacity, equation of state, and chemical diffusion. Through a statistical assessment, we have derived a confident parameter set as the best solution which minimized Χ^2 within the observational error domain. Most of all, we found that 85 Peg is not a binary system but a triple system with an unseen companion 85 Peg Bb~0.16M_⨀. The aim of the present paper is (1) to provide a complete modelling of the stellar system based on the evolutionary theory, and (2) to constrain the physical dimensions such as mass, metallicity and age. http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2007/v24n1/OJOOBS_2007_v24n1_31.pdfstarsstellar evolutionstellar atmospherevisual binariesspectroscopic binaries85 Peg |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kiehunn Bach Yong-Cheol Kim Pierre Demarque |
spellingShingle |
Kiehunn Bach Yong-Cheol Kim Pierre Demarque CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM Journal of Astronomy and Space Sciences stars stellar evolution stellar atmosphere visual binaries spectroscopic binaries 85 Peg |
author_facet |
Kiehunn Bach Yong-Cheol Kim Pierre Demarque |
author_sort |
Kiehunn Bach |
title |
CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM |
title_short |
CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM |
title_full |
CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM |
title_fullStr |
CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM |
title_full_unstemmed |
CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM |
title_sort |
calibration of stellar parameters of 85 peg system |
publisher |
Korean Space Science Society (KSSS) |
series |
Journal of Astronomy and Space Sciences |
issn |
2093-5587 2093-1409 |
publishDate |
2007-03-01 |
description |
We have investigated the evolutionary status of 85 Peg within the framework of standard evolutionary theory. 85 Peg has been known to be a visual and spectroscopic binary system in the solar neighborhood. In spite of the accurate information of the total mass (~1.5M_⨀) and the distance (~12pc) from the HIPPARCOS parallax, it has been undetermined an individual mass, therefore the evolved status of the system. Moreover, the coupled uncertainties of chemical composition and age, make matters worse in predicting an evolutionary status of the system. Nevertheless, we computed the various possible models for 85 Peg, and then calibrated stellar parameters by adjusting to the recent observational data. Our modelling computation has included recently updated input physics and stellar theory such as opacity, equation of state, and chemical diffusion. Through a statistical assessment, we have derived a confident parameter set as the best solution which minimized Χ^2 within the observational error domain. Most of all, we found that 85 Peg is not a binary system but a triple system with an unseen companion 85 Peg Bb~0.16M_⨀. The aim of the present paper is (1) to provide a complete modelling of the stellar system based on the evolutionary theory, and (2) to constrain the physical dimensions such as mass, metallicity and age.
|
topic |
stars stellar evolution stellar atmosphere visual binaries spectroscopic binaries 85 Peg |
url |
http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2007/v24n1/OJOOBS_2007_v24n1_31.pdf |
work_keys_str_mv |
AT kiehunnbach calibrationofstellarparametersof85pegsystem AT yongcheolkim calibrationofstellarparametersof85pegsystem AT pierredemarque calibrationofstellarparametersof85pegsystem |
_version_ |
1725557331905740800 |