Absolute dimensions of eclipsing binaries. V. VV Pyxidis, a detached early A-type system with equal components.
Abstract
New, accurate spectroscopic and photometric observations of the detached early A-type double-lined eclipsing binary VV Pyx (HR 3335, P = 4d. 60) have been analyzed in order to determine masses and radii for its components (Table 8). The spectroscopic orbits are based on 28 coude spectrograms of 12 Åmm-1 dispersion and define the masses to a precision of about 1%. The uvby light curves or the contribution from the visual companion. Residual uncertainties in the amount of third light has negligible influence on the derived stellar parameters. The two components of VV Pyx are virtually identical in mass radius and temperature, and have evolved into the upper part of the main-sequence band. When comparing with the theoretical stellar evolution models by Mejlesen (1980), VV Pyx corresponds most nearly to those of the composition (X, Z) = (0.70, 0.02), found to fit the well-determined B-type systems. Most other A-type systems of similar mass and evolutionary stage generally have rather lower temperatures for their mass than VV Pyx, and are best represented by more metal rich and/or helium poor models. VV Pyx exhibits slow apsidal motion, a significant fraction of which is of relativistic origin. The period is about 3200 yr. The visual companion to VV Pyx appears to be a mainsequence A 5-A 7 star, itself perhaps a spectroscopic binary.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1984
- Bibcode:
- 1984A&A...134..147A
- Keywords:
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- A Stars;
- Eclipsing Binary Stars;
- Stellar Magnitude;
- Stellar Mass;
- Stellar Motions;
- Stellar Spectrophotometry;
- Apsides;
- Light Curve;
- Orbital Elements;
- Radial Velocity;
- Stellar Evolution;
- Stellar Structure;
- Ubv Spectra;
- Astronomy