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Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

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:43 Percentile:96.93(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 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$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.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

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:259 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.

Journal Articles

Possible antimagnetic rotation band and neutron alignment in $$^{101}$$Pd

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:66.88(Physics, Nuclear)

High spin states of $$^{101}$$Pd have been studied through in-beam $$gamma$$-ray spectroscopy by using the reaction $$^{68}$$Zn ($$^{37}$$Cl, 1$$p$$3$$n$$). The band based on the $$h$$$$_{11/2}$$ neutron orbital has been extended to higher-spin states, and the band based on the $$d$$$$_{5/2}$$ 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 $$h$$$$_{11/2}$$ band to the $$d$$$$_{5/2}$$ band have been also observed. The structure of the $$h$$$$_{11/2}$$ band was discussed from the viewpoint of "antimagnetic rotation" based on a semiclassical particle plus rotor model taking neutron alignments into account.

Journal Articles

Reduction of intrinsic critical current density under a magnetic field along the hard axis of a free layer in a magnetic tunnel junction

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:5.4(Materials Science, Multidisciplinary)

Journal Articles

Search for signature inversion in the $$pi i_{13/2} bigotimes nu i_{13/2}$$ bands in $$^{182,184,186}$$Au

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:28.19(Physics, Nuclear)

Search for low-spin signature inversion in the $$pi i_{13/2} bigotimes nu i_{13/2}$$ bands in odd-odd $$^{182,184,186}$$Au have been made through in-beam $$gamma$$-ray spectroscopy techniques. The $$pi i_{13/2} bigotimes nu i_{13/2}$$ bands in the three nuclei have been identified and extended up to high-spin states. In particlular, the interband connection between the $$pi i_{13/2} bigotimes nu i_{13/2}$$ band and the ground-state band in $$^{184}$$Au have been established, leading to a firm spin-and-parity assignment for the $$pi i_{13/2} bigotimes nu i_{13/2}$$ band. The low-spin signature inversion is found in the $$pi i_{13/2} bigotimes nu i_{13/2}$$ bands in $$^{182,184,186}$$Au.

Journal Articles

Coulomb excitation experiments at JAEA Tandem facility for the study of nuclear structure

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

Journal Articles

A New isomer in $$^{136}$$Ba populated by deep inelastic collisions

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 $$^{136}$$Ba, populated in deep-inelastic collisions by the interaction of 450-MeV $$^{82}$$Se ions with a $$^{139}$$La target, have been studied by means of in-beam $$gamma$$-ray spectroscopy. A new isomer with $$I^pi=(10^+)$$ has been identified at an excitation energy of $$E_x=3.357$$ MeV. The half-life was determined as $$T_{1/2}=94pm10$$ ns. The extracted $$B(E2)$$ value is much smaller than those in $$^{132}$$Te and $$^{134}$$Xe. This hindrance is investigated by a shell model calculation.

Journal Articles

Multi-quasiparticle excitations in $$^{145}$$Tb

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:48.06(Physics, Nuclear)

no abstracts in English

Journal Articles

Multiple coulomb excitation experiment of $$^{68}$$Zn

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:72.52(Physics, Nuclear)

Coulomb excitation experiment was carried out with a $$^{68}$$Zn beam bombarding a $$^{nat}$$Pb target. Two $$E2$$ matrix elements and the quadrupole moment of the 2$$_{1}$$$$^{+}$$ 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 $$1g_{9/2}$$ 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.

Journal Articles

High spin states in $$^{158}$$Dy

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:21.31(Physics, Nuclear)

no abstracts in English

Journal Articles

Multiple Coulomb Excitation Experiment of $$^{66}$$Zn

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:68.45(Physics, Nuclear)

no abstracts in English

Journal Articles

Inelastic excitation of $$^{187}$$Re

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:55.62(Physics, Nuclear)

High-spin states in $$^{187}$$Re populated by inelastic scattering of a 500-MeV $$^{82}$$Se beam have been studied by means of in-beam $$gamma$$-ray spectroscopy. Levels built on the $$5/2^+$$[402] and $$9/2^-$$[514] one-quasiparticle states were measured up to $$I^pi=(21/2^+)$$ and $$(21/2^-)$$, 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.

Journal Articles

Projectile Coulomb excitation of $$^{78}$$Se

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:69.91(Physics, Nuclear)

no abstracts in English

Journal Articles

Electric-dipole transition probabilities between yrast bands in $$^{157}$$Gd

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:55.62(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

Rotaional alignment of the h$$_{11/2}$$ band in $$^{157}$$Dy

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:48.02(Physics, Nuclear)

no abstracts in English

Journal Articles

First measurement of the quadrupole moment in the 2$$_1^+$$ state of $$^{84}$$Kr

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:51.12(Astronomy & Astrophysics)

A $$^{84}$$Kr beam was Coulomb-excited on a $$^{98}$$Mo target and a $$^{nat}$$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$$_1^+$$ was newly obtained. The measured quadrupole moment and the $$B(E2)$$ values are consistent with large-scale shell-model calculations which give a systematic description of $$N$$,=,50 isotones.

Journal Articles

Configuration-dependent band structures in odd-odd $$^{180}$$Ir

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:70.12(Physics, Nuclear)

no abstracts in English

Journal Articles

A Position-sensitive particle detector for Coulomb excitation experiment

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:47.89(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Multiple Coulomb excitation of a $$^{76}$$Ge beam

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:35 Percentile:84.98(Physics, Nuclear)

no abstracts in English

Journal Articles

Coulomb excitation of $$^{74}$$Ge beam

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:53 Percentile:90(Physics, Nuclear)

no abstracts in English

33 (Records 1-20 displayed on this page)