no code implementations • 4 Mar 2021 • Stevanus K. Nugroho, Hajime Kawahara, Neale P. Gibson, Ernst J. W. de Mooij, Teruyuki Hirano, Takayuki Kotani, Yui Kawashima, Kento Masuda, Matteo Brogi, Jayne L. Birkby, Chris A. Watson, Motohide Tamura, Konstanze Zwintz, Hiroki Harakawa, Tomoyuki Kudo, Masayuki Kuzuhara, Klaus Hodapp, Masato Ishizuka, Shane Jacobson, Mihoko Konishi, Takashi Kurokawa, Jun Nishikawa, Masashi Omiya, Takuma Serizawa, Akitoshi Ueda, Sébastien Vievard
Nonetheless, this marginal detection is consistent with the prediction that H$_{2}$O is mostly thermally dissociated in the upper atmosphere of the ultra-hot Jupiters.
Earth and Planetary Astrophysics
1 code implementation • 26 Jul 2020 • Hajime Kawahara, Kento Masuda
We then extend this analytic framework to a time-varying one through a Gaussian process in time domain, and present analytic expressions that enable efficient sampling from a full joint posterior distribution of geography, axial tilt, spin rotation period, and hyperparameters in the Gaussian-process priors.
Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics Methodology
no code implementations • 19 Jun 2020 • Yuta Nakagawa, Takanori Kodama, Masaki Ishiwatari, Hajime Kawahara, Yasushi Suto, Yoshiyuki O. Takahashi, George L. Hashimoto, Kiyoshi Kuramoto, Kensuke Nakajima, Shin-ichi Takehiro, Yoshi-Yuki Hayashi
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.
Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics
no code implementations • 8 Apr 2020 • Masataka Aizawa, Hajime Kawahara, Siteng Fan
We find that the sparse modeling resolves Australia, Afro-Eurasia, North America, and South America using 2-year observation with a time interval of one month.
Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics
1 code implementation • 8 Apr 2020 • Hajime Kawahara
Photometric variation of a directly imaged planet contains information on both the geography and spectra of the planetary surface.
Earth and Planetary Astrophysics Instrumentation and Methods for Astrophysics
1 code implementation • 10 Apr 2019 • Hajime Kawahara, Kento Masuda
The smaller candidates are more prevalent (23 with $4<r/R_\oplus<8$, 15 with $r/R_\oplus<4$) and suggest that long-period Neptune-sized planets are at least as common as the Jupiter-sized ones, although our sample is yet to be corrected for detection completeness.
Earth and Planetary Astrophysics
1 code implementation • 30 Sep 2018 • Hajime Kawahara, Takami Kuroda, Tomoya Takiwaki, Kazuhiro Hayama, Kei Kotake
We demonstrate that the polarization states that randomly change with time after bounce are associated with the PNS g-mode oscillation, whereas a slowly changing polarization state in the low-frequency domain is connected to the PNS core oscillation.
High Energy Astrophysical Phenomena Instrumentation and Methods for Astrophysics General Relativity and Quantum Cosmology
1 code implementation • 9 Mar 2016 • Hajime Kawahara
We consider the time-frequency analysis of a scattered light curve of a directly imaged exoplanet.
Instrumentation and Methods for Astrophysics Earth and Planetary Astrophysics
1 code implementation • 1 Jun 2011 • Hajime Kawahara, Yuka Fujii
We develop an inversion technique of annual scattered light curves to sketch a two-dimensional albedo map of exoplanets in face-on orbits.
Earth and Planetary Astrophysics
1 code implementation • 28 Apr 2010 • Hajime Kawahara, Yuka Fujii
Scattered lights from terrestrial exoplanets provide valuable information about the planetary surface.
Earth and Planetary Astrophysics
