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《New Astronomy》2016
CCD photometry of the eclipsing W Uma binary system V523 Cas in U, B, V and RC filters was carried out during eight nights in 2012. The physical and geometrical parameters of this system are obtained. A possible pulsation period of one of the components is obtained by analyzing the residuals of the ephemeris light curve. Our observations contain 16 times of minimum light. We combined these with all available published times of minimum. By fitting a quadratic curve to the O-C values, a new ephemeris of the system is calculated. By attributing the period change to mass transfer, we find a mass transfer rate of . Also, Period (80.58 yr) and the minimum mass (0.3 M⊙) of a possible third body is estimated. In addition, the possible existence of a fourth body with a mass of order 0.15 M⊙ is discussed. These third and fourth bodies could be low-mass main-sequence stars (red dwarfs). 相似文献
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《Planetary and Space Science》2006,54(13-14):1445-1456
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《New Astronomy》2016
The C2 molecule is well known for its astrophysical importance. The radiative transition parameters that include Franck-Condon (FC) factor, r-centroid, electronic transition moment, Einstein coefficient, absorption band oscillator strength, effective temperatures and radiative life time have been estimated for the Swan band system of C2 molecule for experimentally observed vibrational levels using RKR (Rydberg–Klein–Rees) potential energy curve. The lifetime for the d3Πg state of C2 molecule was found to be 82.36 ns for the level. A reliable numerical integration method has been used to solve the radial Schrödinger equation for the vibrational wave functions of upper and lower electronic states based on the latest available spectroscopic data and known wavelengths. The estimated radiative transition parameters are tabulated. The effective vibrational temperature of Swan band system of C2 molecule is found agreed with the effective rotational temperature from photosphere spectrum. Hence, the radiative transition parameters and effective temperatures help us to ascertain the presence of C2 molecule in the interstellar medium, photosphere and sunspots. 相似文献
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《Planetary and Space Science》2006,54(13-14):1472-1481
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《New Astronomy》2015
The absolute dimensions of the components of the eccentric eclipsing binary KL CMa have been determined. The solution of light and radial velocity curves of high ( Å) and intermediate ( Å) resolution spectra yielded masses M1 = 3.55 ± 0.27 M⊙, M2 = 2.95 ± 0.24 M⊙ and radii R1 = 2.37 ± 0.09 R⊙, R2 = 1.70 ± 0.1 R⊙ for primary and secondary components, respectively. The system consists of two late B-type components at a distance of 220 ± 20 pc for an estimated reddening of .The present study provides an illustration of spectroscopy’s crucial role in the analysis of binary systems in eccentric orbits. The eccentricity of the orbit () of KL CMa is found to be bigger than the value given in the literature (). The apsidal motion rate of the system has been updated to a new value of , which indicates an apsidal motion period of yrs, two times slower than given in the literature. Using the absolute dimensions of the components yielded a relatively weak relativistic contribution of . The observed internal-structure component () is found to be in agreement with its theoretical value ().Both components of the system are found very close to the zero-age main-sequence and theoretical isochrones indicate a young age ( Myr) for the system. Analysis of the spectral lines yields a faster rotation ( km s−1) for the components than their synchronization velocities ( km s−1, km s−1). 相似文献
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《Planetary and Space Science》2007,55(5):643-650
The planet OGLE-TR-56b is the extrasolar giant planet closest to its host star. This planet and its star exchange extreme tidal forces. This leads to a reduction of the planetary orbit and a spin-up of the stellar rotation. The tidal migration rate depends crucially on the ratio of the tidal dissipation factor and the stellar love number of the star, which is only poorly known and estimates range within . For values greater than no observable influence by tidal forces on the planet's orbit within the lifetime for the star can be found. A lower limit for the possible values of the parameter for the G-type star OGLE-TR-56 was found by studying the evolution of possible tidal interaction into the future and in the past. This study demonstrates that on the basis of conservative model assumptions, a considerable but unrealistic spin-up of the star can be expected if , which is not in agreement with observed stellar rotation periods. From a statistical analysis based on a Monte-Carlo tidal evolution simulation, the parameter can be constrained to the range if the system shall evolve significantly and realistically by tidal forces. 相似文献
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《Planetary and Space Science》2007,55(9):1190-1196
The Swedish Institute of Space Physics is developing a miniature plasma analyzer for planetary missions (MIPA—Miniature ion precipitation analyzer). MIPA has been accepted to fly on-board both the ESA BepiColombo mission to Mercury (2014) and the Indian Chandrayaan—1 mission to the Moon (2007). The analyzer measures ions in the energy range 10 eV–15 keV and has a sufficient mass resolution to resolve the main groups of ions, namely . Field of view is . The instrument consists of the sensor head and a separate electronic board whose total mass is 300 g. The sensor head envelope is roughly in volume and is designed for the extreme operation temperature range of to . MIPA comprises an electrostatic scanner for angular resolution, a cylindrical electrostatic analyzer for energy discrimination and a time-of-flight (TOF) section for particle velocity measurement. Generic design allows using the instrument on various platforms including nano-satellite and multi-spacecraft missions. This document describes the design of the sensor part including ion optical as well as mechanical aspects. 相似文献