The radius and mass of the subgiant star Hyi from interferometry and asteroseismology

Autor: Jane Robertson, Peter G. Tuthill, S. M. Owens, John Davis, A. P. Jacob, John O'Byrne, J. R. North, Timothy R. Bedding, William J. Tango, Michael J. Ireland
Rok vydání: 2007
Předmět:
Zdroj: Monthly Notices of the Royal Astronomical Society: Letters. 380:L80-L83
ISSN: 1745-3933
1745-3925
DOI: 10.1111/j.1745-3933.2007.00355.x
Popis: We have used the Sydney University Stellar Interferometer (SUSI) to measure the angular diameter of beta Hydri. This star is a nearby G2 subgiant whose mean density was recently measured with high precision using asteroseismology. We determine the radius and effective temperature of the star to be 1.814+/-0.017 R_sun (0.9%) and 5872+/-44 K (0.7%) respectively. By combining this value with the mean density, as estimated from asteroseismology, we make a direct estimate of the stellar mass. We find a value of 1.07+/-0.03 M_sun (2.8%), which agrees with published estimates based on fitting in the H-R diagram, but has much higher precision. These results place valuable constraints on theoretical models of beta Hyi and its oscillation frequencies.
3 figures, 3 tables, to appear in MNRAS Letters
Databáze: OpenAIRE
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