Context. The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole ...asteroid population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. Aims. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. Methods. We used classical dense photometric lightcurves from several sources (Uppsala Asteroid Photometric Catalogue, Palomar Transient Factory survey, and from individual observers) and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of asteroids used in our previous paper. Results. We present 119 new asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetic and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.
The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole asteroid ...population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of asteroids used in our previous paper. We present 119 new asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.
We have developed a 1.62\mu \mathrm{m} pixel pitch global shutter sensor optimized for imaging in the near infrared (NIR) and shortwave infrared (SWIR) regions of the light spectrum. This ...breakthrough was made possible through the use of our colloidal Quantum Dot (QD) thin film technology, which we have named Quantum Film (QF). We have scaled up this new platform technology to our 300mm manufacturing toolset. The challenges associated with the introduction of solution-processed, colloidally grown lead sulfide (PbS) QDs in an industrial 300mm fab environment were successfully overcome. The QF photodiodes, leveraging either NIR or SWIR sensitive QDs, were optimized for high quantum efficiency (QE), low dark current and immunity to operating stress. Global shutter pixel arrays, with pixel pitch of 2.2\mu \mathrm{m} and 1.62\mu \mathrm{m} exhibit unprecedented QE of >50% and MTF @ Nyquist/2 of 0.75 and 0.6, respectively. The robustness of our 300mm Quantum Film technology was fully assessed and reliability in terms of meeting all required lifetime specifications for consumer electronics and other potential applications has been demonstrated.
We describe the fabrication and characterization of high speed SiGe:C HBTs using a poly-SiGe emitter. The effects of Ge incorporation into the emitter on the static (gain, BV/sub CEO/) and dynamic ...(f/sub T/, /spl tau//sub ECO/) device characteristics are analyzed. This experiment is used to quantify the impact of the current gain on f/sub T/, and provides an original way to extract the emitter component of the forward transit time.
PDF
