REFINING THE PARALLAX IN VISUAL DOUBLE STARS USING ORBITAL AND SPECTRAL DATA: APPLICATION TO THE SYSTEM OF THE K0 GIANTS, A 1808
- Astronomical Observatory R. M. Aller, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia (Spain)
In this paper, we show how Hipparcos parallaxes of distant visual binaries ({pi}{sub Hip} {approx}< 10 mas) can be refined. This is accomplished by using relevant orbital and spectral data. To this end, we study the pair of K0 giants, A 1808. A revised orbit of this system is presented that was calculated by taking into account a set of interferometric and visual measurements covering almost one orbital revolution. In addition, by analyzing its spectrum obtained with the 2.6 m telescope of the Byurakan Astrophysical Observatory (Armenia), we confirm the MK spectral type, K0III. On the basis of B - V photometric data, we derived the extinction A{sub V} = 0.23 {+-} 0.08 mag as well as obtained a spectroscopic parallax ({pi}{sub sp} = 3.19 {+-} 0.21 mas) with a much smaller relative uncertainty of 6.6% compared with that of Hipparcos (42.1%; {pi}{sub Hip} = 2.43 {+-} 1.00 mas). Accordingly, this system is now placed at 313 {+-} 21 pc. With the obtained spectroscopic parallax, a dynamical mass of 4.52{sup +1.24}{sub -0.90} M{sub sun} is obtained, which agrees well with that expected from standard calibrations.
- OSTI ID:
- 21583041
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 136, Issue 2; Other Information: DOI: 10.1088/0004-6256/136/2/890; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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