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《Planetary and Space Science》2006,54(13-14):1445-1456
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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
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A.A. Nucita S. Carpano F. De Paolis G. Ingrosso B.M.T. Maiolo M. Guainazzi 《New Astronomy》2009,14(3):302-306
The binaries known as cataclysmic variables are particular binary systems in which the primary star (a white dwarf) accretes material from a secondary via Roche-lobe mechanism. Usually, these objects have orbital period of a few hours so that a detailed temporal analysis can be performed. Here, we present Chandra and XMM-Newton observations of a dwarf nova candidate identified in the past by optical observations towards the galactic Bulge and labeled as MACHO 104.20906.960. After a spectral analysis, we used the Lomb-Scargle technique for the period search and evaluated the confidence level using Monte-Carlo simulations. In this case, we found that the X-ray source shows a period of h ( error) so that it is most likely a system of interacting objects. The modulation of the signal was found with a confidence level of . The spectrum can be described by a two thermal plasma components with X-ray flux in the 0.3–10 keV energy band of . We find that the distance of the source is approximately 1 kpc thus corresponding to a luminosity . 相似文献
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《Planetary and Space Science》2006,54(13-14):1472-1481