Light-time orbit and apsidal motion of the eclipsing binary U Ophiuchi

Autor: B. C. Kämper
Rok vydání: 1986
Předmět:
Zdroj: Astrophysics and Space Science. 120:167-189
ISSN: 1572-946X
0004-640X
Popis: A comprehensive period study of the times of minima observed from 1881 to 1985 has been performed. Previous interpretations of the O−C diagram based on light-time effect are confirmed. The light-time orbit of U Oph has been revised using a differential corrections procedure. We get an eccentric orbit withe′=0.22±0.06,P′=38.7±0.2 yr, and a mass function\(f\left( \mathfrak{M} \right) = 0.0044 \pm 0.0005 \mathfrak{M}_ \odot \). In addition, our analysis has revealed short-period apsidal motion (U/P=4515±75) in a slightly eccentric close orbit (e=0.0031±0.0003), allowing a reliable determination of the density concentration coefficient,k2=0.0059±4. A comparison with stellar evolutionary models calculated by Jeffery (1984) yields the helium contentY=0.28±0.05 and an age of 3×107 yr for the components of U Oph.
Databáze: OpenAIRE
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