B and V photometry of HD 81410 obtained on 34 nights between January 3 and March 14 of 1981 is presented. In both B and V, the amplitudes are found to be approximately 0.15 mag. It is also found that a 12.86833 day period satisfies all the available photometric data. Orbital elements of the system are derived from the published radial velocity measurements. The orbital period, strong Ca II H and K emission, and the spectral types of the components suggest that HD 81410 is a member of the RS CVn group. The star is seen to become redder at fainter visual magnitudes. This is attributed to the relatively cooler temperatures of the 'darker regions' present on the visible hemisphere.
Babu, G. S. D; Shylaja, B. S(D. Reidel Publishing Company, 1982-01)
Based on the observed energy distribution curves of about a hundred Ap stars, the various relationships among their physical parameters: namely, the temperatue, colour index, bolometric correction and bolometric magnitude ...
The H α profile in the spectrum of δ Orionis shows phase-dependent changes, with a period of variation equal to the orbital period fo the binary system. The profile shape changes from a normal absorption profile at zero ...
Mallik, D. C. V(Astronomical Society of Australia, 1991)
The review describes some of the progress made in observations and their interpretation, particularly in the context of the evolution of the nebulae and the central stars. It includes a discussion on the improved determinations ...
