Evolutionary constraints on the masses of the components of HDE 226868/Cyg X-1 binary system

Calculations carried out to model the evolution of HDE 226868, under different assumptions about the stellar wind mass loss rate, provide robust limits on the present mass of the star. It has to be in the range 40 +- 5 solar masses if the distance to the system is in the range 1.95 to 2.35 kpc and the effective temperature of HDE 226868 in the range 30000 to 31000 K. Extending the possible intervals of these parameters to 1.8 to 2.35 kpc and 28000 to 32000 K, one gets for the mass of the star the range 40 +- 10 solar masses. Including into the analysis observational properties such as the profiles of the emission lines, rotational broadening of the absorption lines and the ellipsoidal light variations, one can estimate also the mass of the compact component. It has to be in the ranges 20 +- 5 solar masses and 13.5 to 29 solar masses for the cases described above. The same analysis (using the evolutionary models and the observational properties listed above) yields lower limit to the distance to the system of about 2.0 kpc, if the effective temperature of HDE 226868 is higher than 30000 K. This limit to the distance does not depend on any photometric or astrometric considerations.Comment: 11 pages, 4 figures, accepted for publication in MNRA

A candidate for the parent body of the Taurid complex and its search ephemeris

Untypical asteroid 5025 P-L, with its perihelion close to the orbit of Mercury and its aphelion between the orbits of Jupiter and Saturn, seems to be a good candidate for the parent body of the Taurid complex of small interplanetary objects. Evidence that this asteroid is a major source of meteoroids as well as an analysis of the orbits of asteroidal and cometary members of the Taurid complex, lead to the conclusion that 5025 P-L might be regarded as a remnant of a giant comet which was a progenitor of the overall complex according to the hypothesis of Clube and Napier. Unfortunately, the orbit of 5025 P-L is very poorly determined because the computations were based upon only three positional observations over an arc of only four days in October 1960. Any further research on the problem of origin and evolution of the Taurid complex needs better determined orbit of this key asteroid. Therefore its new positions are necessary. In order to enable the search of eventual trails of 5025 P-L on plates which can be found in archives, its ephemeris for the opposition in 1960, when the asteroid passed about 0.5 AU from the Earth, is presented

Excitation of guided waves in layered structures with negative refraction

We study the electromagnetic beam reflection from layered structures that include the so-called double-negative materials, also called left-handed metamaterials. We predict that such structures can demonstrate a giant lateral Goos-Hanchen shift of the scattered beam accompanied by splitting of the reflected and transmitted beams due to the resonant excitation of surface waves at the interfaces between the conventional and double-negative materials as well as due to excitation of leaky modes in the layered structures. The beam shift can be either positive or negative, depending on the type of the guided waves excited by the incoming beam. We also perform finite-difference time-domain simulations and confirm the major effects predicted analytically.Comment: 13 pqages, 10 figures. Also available at http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-2-48