Seismic analysis of 70 Ophiuchi A: A new quantity proposed

  • Tang Y
  • Bi S
  • Gai N
  • 1

    Readers

    Mendeley users who have this article in their library.
  • 5

    Citations

    Citations of this article.

Abstract

The basic intent of this paper is to model 70 Ophiuchi A using the latest asteroseismic observations as complementary constraints and to determine the fundamental parameters of the star. Additionally, we propose a new quantity to lift the degeneracy between the initial chemical composition and stellar age. Using the Yale stellar evolution code (YREC7), we construct a series of stellar evolutionary tracks for the mass range M = 0.85-0.93 Mȯwith different composition Yi(0.26-0.30) and Zi(0.017-0.023). Along these tracks, we select a grid of stellar model candidates that fall within the error box in the HR diagram to calculate the theoretical frequencies, the large- and small-frequency separations using Guenther's stellar pulsation code. Following the asymptotic formula of stellar p-modes, we define a quantity r01which is correlated with stellar age. Also, we test it by theoretical adiabatic frequencies of many models. Many detailed models of 70 Ophiuchi A are listed in Table 3. By combining all non-asteroseismic observations available for 70 Ophiuchi A with these seismological data, we think that Model 60, Model 125 and Model 126, listed in Table 3, are the optimum models presently. Meanwhile, we predict that the radius of this star is about 0.860-0.865 Rȯand the age is about 6.8-7.0 Gyr with mass 0.89-0.90 Mȯ. Additionally, we prove that the new quantity r01can be a useful indicator of stellar age. © 2008 Elsevier B.V. All rights reserved.

Author-supplied keywords

  • Stars: evolution
  • Stars: individual: 70 Ophiuchi A
  • Stars: oscillations

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Y. K. Tang

  • S. L. Bi

  • N. Gai

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free