Search for forced oscillations in binaries. II. β Scorpii A. New physical parameters and a search for line profile variability.
We present new spectroscopic data and physical parameters for the early-type binary system β Sco A. Radial velocity measurements of Reticon spectra have been made using both cross-correlation and disentangling techniques. Spectroscopic orbits, based on the new data and published radial velocities are presented. The orbital period and apsidal motion rate have been refined using 603 radial velocities covering a time interval of 84-years. The anomalistic period is 6.828245+/-0.000009-days, and the apsidal motion rate is ̇(ω)=0.00131+/-0.00004°/day. The first visual-spectroscopic orbit for the system is given here as well, from which we derive a parallax for the system of 0.0070+/-0.0001" corresponding to a distance of 143+/-3pc. This has allowed us to compute the absolute dimensions and mean internal structure constant for the system. We find, for the primary and secondary respectively, masses, radii, and effective temperatures of: m_p_/msun_=13.5+/-0.9, m_s_/msun_=9.6+/-0.4, r_p_/rsun_=6.8+/-0.4, r_s_/rsun_=4.2+/-0.3, T_p_=28000+/-2000K, and T_s_=26400+/-2000K. The corresponding spectral types of the components are B0.5IV-V and B1.5V. Line photometry produced from the disentangling solutions suggests the presence of eclipses in β Sco A, which must be verified through systematic photometry. We also present a tentative detection of possible β Cep -type line profile variability in the secondary.
Astronomy and Astrophysics
- Pub Date:
- June 1997
- STARS: BINARIES: SPECTROSCOPIC;
- STARS: FUNDAMENTAL PARAMETERS;
- STARS: INDIVIDUAL: * BET SCO A