Astron. Astrophys. 343, 990-996 (1999)

Astron. Astrophys. 343, 990-996 (1999)

Helioseismology and the solar age

W.A. Dziembowski^1,2, G. Fiorentini^3,4, B. Ricci^3,4 and R. Sienkiewicz²

¹ Warsaw University Observatory, Al. Ujazdowskie 4, PL-00-478 Warszawa, Poland
² N. Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, PL-00-716 Warszawa, Poland
³ Dipartimento di Fisica dell'Università di Ferrara, via Paradiso 12, I-44100 Ferrara, Italy
⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, via Paradiso 12, I-44100 Ferrara, Italy

Received 5 October 1998 / Accepted 21 December 1998

Abstract

The problem of measuring the solar age by means of helioseismology has been recently revisited by Guenther & Demarque (1997) and by Weiss & Schlattl (1998). Different best values for [FORMULA] and different assessment of the uncertainty resulted from these two works. We show that depending on the way seismic data are used, one may obtain Gy close to the age of the oldest meteorites, Gy, like in the first paper, or above 5 Gy like in the second paper. The discrepancy in the seismic estimates of the solar age may be eliminated by assuming higher than the standard metal abundance and/or an upward revision of the opacities in the solar radiative interior.

We argue that the most accurate and robust seismic measure of the solar age are the small frequency separations, [FORMULA] , for spherical harmonic degrees and radial orders . The seismic age inferred by minimization of the sum of squared differences between the model and the solar small separations is Gy, a number consistent with meteoritic data. Our analysis supports earlier suggestions of using small frequency separations as stellar age indicators.

Key words: Sun: abundances Sun: evolution Sun: interior Sun: oscillations

Send offprint requests to: W.A. Dziembowski

This article contains no SIMBAD objects.

1. Introduction
2. New solar models
3. Inference from seismically determined solar parameters
- 3.1. The sound speed
- 3.2. Helium abundance
- 3.3. Estimates of t_seis based on selected values of u and y_ph
4. Direct and almost direct use of measured frequencies
5. Solar age from small separations
6. Conclusions
Acknowledgements
References

Online publication: March 1, 1999
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Helioseismology and the solar age

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