... Future seminars . P a s t seminars . Seminar council . X-ray observation of middle-aged SNRs " . Prof. Hiroshi Tsunemi (Graduate School of Science, Earth and Space Science Osaka University) . ... We have studied the Cygnus Loop, a typical middle-aged SNR, in X-ray using the Asca and Rosat satellites. ... The shell region, high density region, shows a abundance of the ISM while the inner region, low density region, shows a metal rich abundance originating from the ejecta. ...
... NASA's Hubble Space Telescope has detected a long-sought population of comets dwelling at the icy fringe of the solar system . The observation, which is the astronomical equivalent to finding the proverbial needle-in-a-haystack, bolsters proof for a primordial comet reservoir just beyond Neptune , currently the farthest planet from the Sun . ... The comet-disk lies just beyond Neptune and might stretch 500 times farther from the Sun than Earth . ... Comet Introduction Kuiper Belt Objects . ...