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        검색결과 20

        3.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The second generation of stars in the globular clusters (GCs) of the Milky Way (MW) exhibit unusually high N, Na, or Al, compared to typical Galactic halo stars at similar metallicities. The halo field stars enhanced with such elements are believed to have originated in disrupted GCs or escaped from existing GCs. We identify such stars in the metallicity range −3.0 < [Fe/H] < 0.0 from a sample of ∼36,800 giant stars observed in the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey, and present their dynamical properties. The N-rich population (NRP) and N-normal population (NNP) among our giant sample do not exhibit similarities in either in their metallicity distribution function (MDF) or dynamical properties. We find that, even though the MDF of the NRP looks similar to that of the MW’s GCs in the range of [Fe/H] < −1.0, our analysis of the dynamical properties does not indicate similarities between them in the same metallicity range, implying that the escaped members from existing GCs may account for a small fraction of our N-rich stars, or the orbits of the present GCs have been altered by the dynamical friction of the MW. We also find a significant increase in the fraction of N-rich stars in the halo field in the very metal-poor (VMP; [Fe/H] < −2.0) regime, comprising up to ∼20% of the fraction of the N-rich stars below [Fe/H] = −2.5, hinting that partially or fully destroyed VMP GCs may have in some degree contributed to the Galactic halo. A more detailed dynamical analysis of the NRP reveals that our sample of N-rich stars do not share a single common origin. Although a substantial fraction of the N-rich stars seem to originate from the GCs formed in situ, more than 60% of them are not associated with those of typical Galactic populations, but probably have extragalactic origins associated with Gaia Sausage/Enceladus, Sequoia, and Sagittarius dwarf galaxies, as well as with presently unrecognized progenitors.
        4,800원
        10.
        2019.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present an analysis of the chemical abundances and kinematics of six low-mass dwarf stars, previously claimed to be candidate hypervelocity stars (HVSs). We obtained moderate-resolution ($R\sim6000$) spectra of these stars to estimate the abundances of several chemical elements (Mg, Si, Ca, Ti, Cr, Fe, and Ni), and derived their space velocities and orbital parameters using proper motions from the \gaia\ Data Release 2. All six stars are shown to be bound to the Milky Way, and in fact are not even considered high-velocity stars with respect to the Galactic rest frame. Nevertheless, we attempt to characterize their parent Galactic stellar components by simultaneously comparing their element abundance patterns and orbital parameters with those expected from various Galactic stellar components. We find that two of our program stars are typical disk stars. For four stars, even though their kinematic probabilistic membership assignment suggests membership in the Galactic disk, based on their distinct orbit l properties and chemical characteristics, we cannot rule out exotic origins as follows. Two stars may be runaway stars from the Galactic disk. One star has possibly been accreted from a disrupted dwarf galaxy or dynamically heated from a birthplace in the Galactic bulge. The last object may be either a runaway disk star or has been dynamically heated. Spectroscopic follow-up observations with higher resolution for these curious objects will provide a better understanding of their origin.
        4,500원
        19.
        2006.08 KCI 등재 서비스 종료(열람 제한)
        A new cultivar ofDianthus caryophyIIus "Gamet" was selected from the progenies ofa cross "Master" and "97007-2"in 1998 at the National Horticultural Research Institute, Rural Development Administration. It was fmally selected in 2001 afterthe investigatio
        20.
        2006.08 KCI 등재 서비스 종료(열람 제한)
        A new cultivar ofDianthus caryophyUus "Pavo" was selected from the progenies ofa cross "Sarangbyul" and "TargetWhite" in 1997 at the National Horticultural Research Institute, Rural Development Administration. It was finally selected m 2001after the inves