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        검색결과 26

        5.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the characterization of a massive (mp = 3:91:4Mjup) microlensing planet (OGLE- 2015-BLG-0954Lb) orbiting an M dwarf host (M = 0:33  0:12M ) at a distance toward the Galactic bulge of 0:6+0:4 􀀀0:2 kpc, which is extremely nearby by microlensing standards. The planet-host projected separation is a?  1:2AU. The characterization was made possible by the wide- eld (4 deg2) high cadence (􀀀 = 6 hr􀀀1) monitoring of the Korea Microlensing Telescope Network (KMTNet), which had two of its three telescopes in commissioning operations at the time of the planetary anomaly. The source crossing time t = 16 min is among the shortest ever published. The high-cadence, wide- eld observations that are the hallmark of KMTNet are the only way to routinely capture such short crossings. High-cadence resolution of short caustic crossings will preferentially lead to mass and distance measurements for the lens. This is because the short crossing time typically implies a nearby lens, which enables the measurement of additional e ects (bright lens and/or microlens parallax). When combined with the measured crossing time, these e ects can yield planet/host masses and distance.
        4,000원
        11.
        2005.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spectroscopic data obtained by the Infrared Interferometer Spectrometer (IRIS) aboard Voyager 1 and 2 have been re-visited. Using the spectroscopic data and footprints of the IRIS aperture on the planet, we constructed images of the stratosphere of Jupiter at the emission bands of hydrocarbons including CH4, C2H6, C2H2, C3H4, C6H6, and C2H4. Thermal emission from the hydrocarbons on Jupiter originates from a broad region of the stratosphere extending from 1 to 10 millibars. We averaged the data using a bin of 20 degrees of longitude and latitudes in order to increase signal-to-noise ratios. The resultant images show interesting wave structure in Jupiter's stratosphere. Fourier transform analyses of these images yield wavenumbers 5 - 7 at mid-Northern and mid-Southern latitudes, and these results are different from those resulted from previous ground-based observations and recent Cassini CIRS, suggesting temporal variations on the stratospheric infrared pattern. The comparisons of the Voyager 1 and 2 spectra also show evidence of temporal intensity variations not only on the infrared hydrocarbon polar brightenings of hydrocarbon emissions but also on the stratospheric infrared structure in the temperate regions of Jupiter over the 4 month period between the two Voyager encounters. Short running title: Stratospheric Images of Jupiter derived from Voyager IRIS Spectra.
        4,000원
        12.
        2005.04 구독 인증기관·개인회원 무료
        14.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spectroscopic data between 7 and 15 microns obtained in 1979 by Voyager 1 and 2 Infrared Interferometer Spectrometer (IRIS) have been revisited. Using the spectral data, Jupit.er images have been constructed at the emission bands of hydrocarbons, such as methane, ethane, and acetylene. The resultant. images show differences in emission intensities in the polar regions, suggesting inhomogeneous distributions of the hydrocarbons over the auroral regions of Jupiter.
        3,000원
        15.
        1996.12 구독 인증기관·개인회원 무료
        17.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the 1.5 μm NH3 band, the 2.3 μm CH4 band, the 2.12 μm H2 S(0) pressure-induced absorption, and the continua at 1.58 μm and 2.0 μm (short K-band). All images except those with the 1.58 μm continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about 45° S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric CH4, NH3 or H2. The impact sites observed with the 2.3 μm filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and 2.12 μm filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about 1%. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.
        4,000원
        20.
        1995.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We examined a total of 166 images of 3.5 μm H3+ emission in the auroral regions of Jupiter observed with the Protocam on IRTF in 1991 and 1992, and found that 30 images contain a clearly isolated small emission patch in the vicinity of the northern auroral regions. Two different time sequences of the images show the small patches at the dusk limb in the range of System III longitudes from 270° through 0° to 90°. The small patches in one sequence of the images, which were taken at 10 phase between 240° and 260°, may be related to the 10 flux tube, similarly suggested by Connerney et al. (1993). However, the small patches in the other sequence are separated from Io as much as 80° in longitude. The positions of the small patches in both sequences are deviated equatorward from the 10 footprint oval by 5° - 8° latitude in the longitudinal range of 270° - 360°. A significant modification is required in current Jovian magnetic field models near the Jupiter's surface if the small patches are produced at the foot of the 10 flux tube.
        4,000원
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