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        검색결과 2

        1.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We adopt the PASTEL catalog combined with SIMBAD radial velocities as a testing standard to validate the stellar parameters (effective temperature Teff , surface gravity log g, metallicity [Fe=H] and radial velocity Vr) from the first data release (DR1) of The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. After applying data reduction and temperature constraints to the sample obtained by cross-identification, we compare the stellar parameters from DR1 and PASTEL. The results show that the DR1 results are reliable under certain conditions. We derive a dispersion of 110 K, 0.19 dex, 0.11 dex and 4.91 kms-1 in specified effective temperature ranges, for Teff , log g, [Fe=H] and Vr respectively. Systematic errors are negligible except for those of Vr. In addition, for stars with PASTEL [Fe=H] < —1.5, the metallicities in DR1 are systematically higher than those in PASTEL.
        3,000원
        2.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The physical and chemical properties of prestellar cores, especially massive ones, are still far from being well understood due to the lack of a large sample. The low dust temperature (< 14 K) of Planck cold clumps makes them promising candidates for prestellar objects or for sources at the very initial stages of protostellar collapse. We have been conducting a series of observations toward Planck cold clumps (PCCs) with ground-based radio telescopes. In general, when compared with other star forming samples (e.g. infrared dark clouds), PCCs are more quiescent, suggesting that most of them may be in the earliest phase of star formation. However, some PCCs are associated with protostars and molecular out ows, indicating that not all PCCs are in a prestellar phase. We have identi ed hundreds of starless dense clumps from a mapping survey with the Purple Mountain Observatory (PMO) 13.7-m telescope. Follow-up observations suggest that these dense clumps are ideal targets to search for prestellar objects.
        3,000원