Search

Your search keyword '"Kiyoshi Kuramoto"' showing total 5 results
Start Over Author "Kiyoshi Kuramoto" Journal the astrophysical journal
5 results on '"Kiyoshi Kuramoto"'

1. Volatile Mass Partitioned among the Atmosphere, Mantle, and Core in Proto-Mars

Author

Hiroaki Saito and Kiyoshi Kuramoto

Subjects
Mars, Solar system terrestrial planets, Atmospheric evolution, Planetary cores, Mantle, Planetary structure, Astrophysics, QB460-466
Abstract

We analyze the distribution of volatiles such as water, hydrogen, and carbon within the atmosphere, mantle, and core of Mars during its accretion stages. The partitioning of these volatiles is crucial as it influences the generation of intrinsic magnetic fields, mantle convection, and magmatic activity. The study suggests that the accretion process is responsible for the presence of water and light elements within the Martian mantle and core. We employ a hybrid-type proto-atmosphere model, which considers an upper layer composed of nebula components and a lower layer made up of degassed components from the impact degassing of the simplified building blocks based on the two-component model. Our numerical analysis implies that the formation of a magma ocean at this high temperature and pressure after around the half-size of the present Mars triggers the migration of water vapor, carbon, and hydrogen from the primordial atmosphere into the planetary interior. Ultimately, several 10 ^21 kg of water could have been distributed to the mantle and, if degassed again by the formation of flood basalts on the Tharsis Plateau, could have supplied Mars’ ancient oceans. Meanwhile, several 10 ^20 kg of carbon and 10 ^19 kg of hydrogen (equivalent to 10 ^20 kg H _2 O) were found to be distributed in the core. Although the distribution of sulfur was simplified so that all of the sulfur is in the core, a result of sulfur accounting for 14 wt% to 19 wt.% of the core mass would be consistent with the core density suggested by InSight.

Published
2024
Full Text
View/download PDF

2. Obliquity of an Earth-like Planet from Frequency Modulation of Its Direct-imaged Lightcurve: Mock Analysis from General Circulation Model Simulation

Author

George Hashimoto, Kiyoshi Kuramoto, Yoshiyuki Takahashi, Takanori Kodama, Shin-ichi Takehiro, Kensuke Nakajima, Masaki Ishiwatari, Yoshi-Yuki Hayashi, Yasushi Suto, Hajime Kawahara, and Yuta Nakagawa

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, Spitzer Space Telescope, Planet, 0103 physical sciences, Radiative transfer, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Mathematical model, Planetary habitability, Astronomy, Astronomy and Astrophysics, Orbital period, Exoplanet, Atmosphere of Earth, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Direct-imaging techniques of exoplanets have made significant progress recently, and will eventually enable to monitor photometric and spectroscopic signals of earth-like habitable planets in the future. The presence of clouds, however, would remain as one of the most uncertain components in deciphering such direct-imaged signals of planets. We attempt to examine how the planetary obliquity produce different cloud patterns by performing a series of GCM (General Circulation Model) simulation runs using a set of parameters relevant for our Earth. Then we use the simulated photometric lightcurves to compute their frequency modulation due to the planetary spin-orbit coupling over an entire orbital period, and attempt to see to what extent one can estimate the obliquity of an Earth-twin. We find that it is possible to estimate the obliquity of an Earth-twin within the uncertainty of several degrees with a dedicated 4 m space telescope at 10 pc away from the system if the stellar flux is completely blocked. While our conclusion is based on several idealized assumptions, a frequency modulation of a directly-imaged earth-like planet offers a unique methodology to determine its obliquity., Comment: 29 pages, 18 figures, accepted for publication in ApJ

Published
2020

3. D/H Ratio in the Interiors of Rocky Protoplanets Accreting in the Solar Nebula

Author

Hiroaki Saito and Kiyoshi Kuramoto

Subjects
Physics, Isotope, Hydrogen, Stable isotope ratio, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, Meteorite, chemistry, Deuterium, Space and Planetary Science, Formation and evolution of the Solar System, Protoplanet, Dimensionless quantity
Published
2020

4. Near-Infrared Brightness of the Galilean Satellites Eclipsed in Jovian Shadow: A New Technique to Investigate Jovian Upper Atmosphere

Author

Yukihiro Takahashi, Yutaka Hayano, Mai Shirahata, Shuji Matsuura, Kiyoshi Kuramoto, Yosuke Minowa, Eiichi Egami, Jason Surace, Ko Arimatsu, Taishi Nakamoto, Jun Kimura, Kohji Tsumura, Takehiko Wada, Chikatoshi Honda, and Kensuke Nakajima

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, eclipses, Jovian, Luminosity, Galilean moons, Jupiter, symbols.namesake, Spitzer Space Telescope, Space and Planetary Science, Planet, Physics::Space Physics, symbols, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Eclipse, atmospheric effects, planets and satellites: individual (Jupiter
Abstract

著者人数: 15名, Accepted: 2014-05-20, 資料番号: SA1140086000

Published
2014

5. THE COSMIC-RAY ENERGY SPECTRUM OBSERVED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

Author

Elliott Barcikowski, John Belz, Dmitri Ivanov, H. Fujii, Thomas Stroman, Y. Murano, K. Kitamoto, K. Yamazaki, A. L. Sampson, Tareq Abu-Zayyad, R. Yamane, Zach Zundel, Mayuko Minamino, E. J. Cho, Younghoon Kwon, Yasunori Kitamura, Takayuki Tomida, K. Ikuta, Y. Yoneda, Akitoshi Oshima, S. Kawana, T. Shirahama, S. I. Lim, Michiyuki Chikawa, Inkyu Park, Nobuyuki Sakurai, ByongGu Cheon, L. M. Scott, Tomoyuki Nakamura, S. Kitamura, Y. Hayashi, T. Fujii, V.A. Kuzmin, William Hanlon, Fumiya Shibata, Fumio Kakimoto, H. Kawai, Yoshiki Tsunesada, S. Kawakami, T. Okuda, Hiroyuki Sagawa, K. Nagasawa, H. Shimodaira, S. W. Nam, S. Y. Roh, S. Yoshida, Naoya Inoue, Ross Anderson, H. Tanaka, H. Yoshii, H. Ukai, Daisuke Ikeda, S. R. Stratton, Yukio Uchihori, Katsuaki Kasahara, Tiffany Wong, R. Ishimori, Toshio Matsuyama, K. Oki, Priti Shah, Yukio Takahashi, K. Tsutsumi, T. Fukuda, Masaki Fukushima, J. H. Kim, Yuichiro Tameda, John N. Matthews, Maxim Pshirkov, M. Tanaka, Y. Kondo, K. Hibino, S. Udo, C. C. H. Jui, T. Kanbe, J. I. Shin, H. Tokuno, Eiji Kido, S. Machida, Toshiyuki Nonaka, Yoji Kobayashi, Tatsunobu Shibata, Kenichi Tanaka, S. Nagataki, Masahiro Takeda, Ken Honda, T. Iguchi, J. D. Smith, Peter Tinyakov, S. B. Thomas, Samuel Blake, B. T. Stokes, Grigory Rubtsov, Isaac Myers, Gordon Thomson, M. Ohnishi, K. Miyata, Shoichi Ogio, Sergey Troitsky, Kiyoshi Kuramoto, Shunsuke Ozawa, Akimichi Taketa, Igor Tkachev, Pierre Sokolsky, R. Cady, K. Hayashi, R. Azuma, T. Matsuura, Oleg Kalashev, D. Rodriguez, G. Vasiloff, R. Aida, W. R. Cho, Hyun-Il Kim, Jyunsei Chiba, Takaaki Ishii, Y. Tsuyuguchi, Dongsu Ryu, K. Martens, HangBae Kim, Naoaki Hayashida, Masato Takita, Tomohiro Matsuda, M. Wood, Kenichi Kadota, B. K. Shin, S. Iwamoto, K. Kobayashi, H. Yamaoka, Y. Wada, S. Suzuki, Y. Yamakawa, Douglas Bergman, H. Ohoka, D. Oku, K. Hiyama, J. Yang, J. Lan, X. Zhou, Mark Allen, and R. Zollinger

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Surface (mathematics), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, Detector, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, 01 natural sciences, 7. Clean energy, law.invention, Computational physics, Telescope, Space and Planetary Science, law, 0103 physical sciences, Energy spectrum, Cutoff, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Energy (signal processing)
Abstract

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays with primary energies above 1.6 x 10^(18) eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 x 10^(18) eV and a steepening at 5.4 x 10^(19) eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of ultra-high energy cosmic ray surface detector data, that involves generating a complete simulation of ultra-high energy cosmic rays striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the "thinning" approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned., Comment: Accepted for publication by Astrophysical Journal Letters

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results