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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count:44 Percentile:96.99(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count:262 Percentile:99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Sugawara, Masahiko*; Hayakawa, Takehito; Oshima, Masumi*; Toh, Yosuke; Osa, Akihiko; Matsuda, Makoto; Shizuma, Toshiyuki; Hatsukawa, Yuichi; Kusakari, Hideshige*; Morikawa, Tsuneyasu*; et al.
Physical Review C, 86(3), p.034326_1 - 034326_11, 2012/09
Times Cited Count:17 Percentile:68.14(Physics, Nuclear)High spin states of Pd have been studied through in-beam -ray spectroscopy by using the reaction Zn (Cl, 13). The band based on the neutron orbital has been extended to higher-spin states, and the band based on the neutron orbital has been somewhat revised. Many transitions decaying to these bands have been observed and consequently, several side bands have been established. Electric dipole transitions from the band to the band have been also observed. The structure of the band was discussed from the viewpoint of "antimagnetic rotation" based on a semiclassical particle plus rotor model taking neutron alignments into account.
Miura, Katsuya*; Sugano, Ryoko*; Ichimura, Masahiko*; Hayakawa, Jun*; Ikeda, Shoji*; Ohno, Hideo*; Maekawa, Sadamichi
Physical Review B, 84(17), p.174434_1 - 174434_7, 2011/11
Times Cited Count:1 Percentile:5.36(Materials Science, Multidisciplinary)Zhang, Y. H.*; Zhou, X. H.*; He, J. J.*; Liu, Z.*; Fang, Y. D.*; Guo, W. T.*; Lei, X. G.*; Guo, Y. X.*; Ndontchueng, M. M.*; Ma, L.*; et al.
International Journal of Modern Physics E, 15(7), p.1437 - 1445, 2006/10
Times Cited Count:3 Percentile:28.13(Physics, Nuclear)Search for low-spin signature inversion in the bands in odd-odd Au have been made through in-beam -ray spectroscopy techniques. The bands in the three nuclei have been identified and extended up to high-spin states. In particlular, the interband connection between the band and the ground-state band in Au have been established, leading to a firm spin-and-parity assignment for the band. The low-spin signature inversion is found in the bands in Au.
Koizumi, Mitsuo; Toh, Yosuke; Osa, Akihiko; Kimura, Atsushi; Utsuno, Yutaka; Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi; Katakura, Junichi; Matsuda, Makoto; et al.
Proceedings of the International Workshop on Quark Nuclear Physics 2006, p.245 - 252, 2006/00
no abstracts in English
Shizuma, Toshiyuki; Gan, Z. G.*; Ogawa, Kengo*; Nakada, Hitoshi*; Oshima, Masumi; Toh, Yosuke; Hayakawa, Takehito; Hatsukawa, Yuichi; Sugawara, Masahiko*; Utsuno, Yutaka; et al.
European Physical Journal A, 20(2), p.207 - 210, 2004/04
Times Cited Count:13 Percentile:71.74(Physics, Nuclear)Excited states in Ba, populated in deep-inelastic collisions by the interaction of 450-MeV Se ions with a La target, have been studied by means of in-beam -ray spectroscopy. A new isomer with has been identified at an excitation energy of MeV. The half-life was determined as ns. The extracted value is much smaller than those in Te and Xe. This hindrance is investigated by a shell model calculation.
Zheng, Y.*; Zhou, X. H.*; Zhang, Y. H.*; Hayakawa, Takehito; Oshima, Masumi; Toh, Yosuke; Shizuma, Toshiyuki; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; et al.
Journal of Physics G; Nuclear and Particle Physics, 30(4), p.465 - 479, 2004/04
Times Cited Count:8 Percentile:48.04(Physics, Nuclear)no abstracts in English
Koizumi, Mitsuo; Seki, Akiyuki*; Toh, Yosuke; Osa, Akihiko; Utsuno, Yutaka; Kimura, Atsushi; Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi; Katakura, Junichi; et al.
Nuclear Physics A, 730(1-2), p.46 - 58, 2004/01
Times Cited Count:20 Percentile:72.44(Physics, Nuclear)Coulomb excitation experiment was carried out with a Zn beam bombarding a Pb target. Two matrix elements and the quadrupole moment of the 2 state were newly derived with the least-squares search code GOSIA. The potential energy surface (PES) was calculated with the Nilsson-Strutinsky model, showing two shallow minima: the first minimum does not contain the orbit below the Fermi surface, while the second minimum does. The ground state band and the intruder band seem to be constructed on the first and the second minimum, respectively. As for the ground state band, the asymmetric rotor model and the IBM in O(6) limit reproduced the experimental values rather well. The shallow PES may suggest unstability of the shape. The ground state band structure may be explained assuming a soft triaxial deformation.
Hayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Shizuma, Toshiyuki; Katakura, Junichi; Iimura, Hideki; Mitarai, Shiro*; Zhang, Y.*; et al.
Physical Review C, 68(6), p.067303_1 - 067303_4, 2003/12
Times Cited Count:2 Percentile:21.20(Physics, Nuclear)no abstracts in English
Koizumi, Mitsuo; Seki, Akiyuki*; Toh, Yosuke; Oshima, Masumi; Osa, Akihiko; Kimura, Atsushi; Hatsukawa, Yuichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Matsuda, Makoto; et al.
European Physical Journal A, 18(1), p.87 - 92, 2003/10
Times Cited Count:16 Percentile:68.31(Physics, Nuclear)no abstracts in English
Shizuma, Toshiyuki; Toh, Yosuke; Oshima, Masumi; Sugawara, Masahiko*; Matsuda, Makoto; Hayakawa, Takehito; Koizumi, Mitsuo; Osa, Akihiko; Zhang, Y. H.*; Liu, Z.*
European Physical Journal A, 17(2), p.159 - 165, 2003/06
Times Cited Count:10 Percentile:55.49(Physics, Nuclear)High-spin states in Re populated by inelastic scattering of a 500-MeV Se beam have been studied by means of in-beam -ray spectroscopy. Levels built on the [402] and [514] one-quasiparticle states were measured up to and , respectively. In additions, several new levels including an isomer at 1682 keV with a half-life of 114(23) ns have been found. Quasiparticle configurations of the levels and the transition rates are discussed.
Hayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Osa, Akihiko; Koizumi, Mitsuo; Hatsukawa, Yuichi; Utsuno, Yutaka; Katakura, Junichi; Matsuda, Makoto; Morikawa, Tsuneyasu*; et al.
Physical Review C, 67(6), p.064310_1 - 064310_6, 2003/06
Times Cited Count:17 Percentile:69.82(Physics, Nuclear)no abstracts in English
Hayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Shinohara, Nobuo; Iimura, Hideki; Shizuma, Toshiyuki; Zhang, Y.*; Sugawara, Masahiko*; et al.
Physics Letters B, 551(1-2), p.79 - 85, 2003/01
Times Cited Count:10 Percentile:55.49(Astronomy & Astrophysics)no abstracts in English
Hayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Katakura, Junichi; Iimura, Hideki; Shizuma, Toshiyuki; Mitarai, Shiro*; Sugawara, Masahiko*; et al.
European Physical Journal A, 15(3), p.299 - 302, 2002/11
Times Cited Count:9 Percentile:47.98(Physics, Nuclear)no abstracts in English
Osa, Akihiko; Czosnyka, T.*; Utsuno, Yutaka; Mizusaki, Takahiro*; Toh, Yosuke; Oshima, Masumi; Koizumi, Mitsuo; Hatsukawa, Yuichi; Katakura, Junichi; Hayakawa, Takehito; et al.
Physics Letters B, 546(1-2), p.48 - 54, 2002/10
Times Cited Count:10 Percentile:51.06(Astronomy & Astrophysics)A Kr beam was Coulomb-excited on a Mo target and a Ta target. Six reduced matrix elements for 5 low-lying states were derived from the analysis using the least-squares code GOSIA. The quadrupole moment of the 2 was newly obtained. The measured quadrupole moment and the values are consistent with large-scale shell-model calculations which give a systematic description of ,=,50 isotones.
Zhang, Y.*; Hayakawa, Takehito; Oshima, Masumi; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; Kusakari, Hideshige*; Sugawara, Masahiko*; Komatsubara, Tetsuro*; Furuno, Kohei*
Physical Review C, 65(1), p.014302_1 - 014302_15, 2002/01
Times Cited Count:20 Percentile:69.99(Physics, Nuclear)no abstracts in English
Toh, Yosuke; Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi; Katakura, Junichi; Matsuda, Makoto; Iimura, Hideki; Kusakari, Hideshige*; Nishimiya, Daisuke*; Sugawara, Masahiko*; et al.
Review of Scientific Instruments, 73(1), p.47 - 50, 2002/01
Times Cited Count:9 Percentile:47.85(Instruments & Instrumentation)no abstracts in English
Toh, Yosuke; Czosnyka, T.*; Oshima, Masumi; Hayakawa, Takehito; Kusakari, Hideshige*; Sugawara, Masahiko*; Osa, Akihiko; Koizumi, Mitsuo; Hatsukawa, Yuichi; Katakura, Junichi; et al.
Journal of Physics G; Nuclear and Particle Physics, 27(7), p.1475 - 1480, 2001/07
Times Cited Count:36 Percentile:85.38(Physics, Nuclear)no abstracts in English
Toh, Yosuke; Czosnyka, T.*; Oshima, Masumi; Hayakawa, Takehito; Kusakari, Hideshige*; Sugawara, Masahiko*; Hatsukawa, Yuichi; Katakura, Junichi; Shinohara, Nobuo; Matsuda, Makoto
European Physical Journal A, 9(3), p.353 - 356, 2000/11
Times Cited Count:54 Percentile:90.25(Physics, Nuclear)no abstracts in English