A large number of cosmic dust particles, micrometeorites and volcanic dust bands have been found and collected in Antarctic ice, snow and glacial sediments, especially in meteorite concentrated regions. Extraterrestri...A large number of cosmic dust particles, micrometeorites and volcanic dust bands have been found and collected in Antarctic ice, snow and glacial sediments, especially in meteorite concentrated regions. Extraterrestrial spherules also have been discovered from the stratosphere and deep-sea sediments. On the basis of their distributive characteristics the cosmic dust particles are classified into interplanetary dust particles and interstellar dust particles. According to their origins cosmic dust particles can be divided into cometary origin particles, asteroidal origin particles, ablation particles from meteorites and interstellar origin particles. The criteria for identifying cosmic dust particles have been established and the origins of cosmic dust particles are also discussed in aegis paper.展开更多
Star-forming regions are often associated with nebulosity. In this study, we investigated infrared diffuse emission in Spitzer IRAC images. The infrared nebula L1527 traces outflows emanating from a low-mass protostar...Star-forming regions are often associated with nebulosity. In this study, we investigated infrared diffuse emission in Spitzer IRAC images. The infrared nebula L1527 traces outflows emanating from a low-mass protostar. The nebular color is consistent with the color of a stellar photosphere with large extinction. Nebulae around the HII region W5-East are bright in the infrared. These colors are consistent with the model color of dust containing polycyclic aromatic hydrocarbon (PAH). The strength of ultraviolet irradiation of the nebulae and the small dust fraction were deduced from the infrared colors of the nebulae. We found that the edges of the nebulae are irradiated by strong ultraviolet radiation and have abundant small dust. Dust at the surface of the molecular cloud is thought to be destroyed by ultraviolet radiation from an early-type star.展开更多
文摘A large number of cosmic dust particles, micrometeorites and volcanic dust bands have been found and collected in Antarctic ice, snow and glacial sediments, especially in meteorite concentrated regions. Extraterrestrial spherules also have been discovered from the stratosphere and deep-sea sediments. On the basis of their distributive characteristics the cosmic dust particles are classified into interplanetary dust particles and interstellar dust particles. According to their origins cosmic dust particles can be divided into cometary origin particles, asteroidal origin particles, ablation particles from meteorites and interstellar origin particles. The criteria for identifying cosmic dust particles have been established and the origins of cosmic dust particles are also discussed in aegis paper.
文摘Star-forming regions are often associated with nebulosity. In this study, we investigated infrared diffuse emission in Spitzer IRAC images. The infrared nebula L1527 traces outflows emanating from a low-mass protostar. The nebular color is consistent with the color of a stellar photosphere with large extinction. Nebulae around the HII region W5-East are bright in the infrared. These colors are consistent with the model color of dust containing polycyclic aromatic hydrocarbon (PAH). The strength of ultraviolet irradiation of the nebulae and the small dust fraction were deduced from the infrared colors of the nebulae. We found that the edges of the nebulae are irradiated by strong ultraviolet radiation and have abundant small dust. Dust at the surface of the molecular cloud is thought to be destroyed by ultraviolet radiation from an early-type star.
