7. Planetary science

Dynamic precise orbit determination of Hayabusa2 using laser altimeter (LIDAR) and image tracking data sets

The precise orbit of the Hayabusa2 spacecraft with respect to asteroid Ryugu is dynamically determined using the data sets collected by the spacecraft’s onboard laser altimeter (LIght Detection And Ranging, LI...

Authors: Keiko Yamamoto, Toshimichi Otsubo, Koji Matsumoto, Hirotomo Noda, Noriyuki Namiki, Hiroshi Takeuchi, Hitoshi Ikeda, Makoto Yoshikawa, Yukio Yamamoto, Hiroki Senshu, Takahide Mizuno, Naru Hirata, Ryuhei Yamada, Yoshiaki Ishihara, Hiroshi Araki, Shinsuke Abe…

Evaluation of a method to retrieve temperature and wind velocity profiles of the Venusian nightside mesosphere from mid-infrared CO₂ absorption line observed by heterodyne spectroscopy

We evaluated a method for retrieving vertical temperature and Doppler wind velocity profiles of the Venusian nightside mesosphere from the CO₂ absorption line resolved by mid-infrared heterodyne spectroscopy. The...

Authors: Kosuke Takami, Hiromu Nakagawa, Hideo Sagawa, Pia Krause, Isao Murata, Yasumasa Kasaba, Takeshi Kuroda, Shohei Aoki, Toru Kouyama, Theodor Kostiuk, Timothy A. Livengood and Gabriella Gilli

Curie temperature of weakly shocked target basalts at the Lonar impact crater, India

The study investigates Curie temperature (T_C), bulk magnetic susceptibility, hysteresis, and X-ray diffraction pattern of in situ target basalts of Lonar impact crater, India. The main magnetic phase in the targe...

Authors: A. Agarwal and L. M. Alva-Valdivia

Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus

The reason for stationary gravity waves at Venus’ cloud top to appear mostly at low latitudes in the afternoon is not understood. Since a neutral layer exists in the lower part of the cloud layer, the waves sh...

Authors: Takeru Yamada, Takeshi Imamura, Tetsuya Fukuhara and Makoto Taguchi

Orbital evolution of a circumbinary planet in a gaseous disk

Sub-Jupiter classed circumbinary planets discovered in close-in binary systems have orbits just beyond the dynamically unstable region, which is determined by the eccentricity and mass ratio of the host binary...

Authors: Akihiro Yamanaka and Takanori Sasaki

The layered structure model for winonaite parent asteroid implicated by textural and mineralogical diversity

The winonaites are primitive achondrites that are associated with IAB iron meteorites. They provide valuable insights into differentiation processes on asteroids in the early Solar System. However, there is st...

Authors: Xiaojia Zeng, Yingli Shang, Shijie Li, Xiongyao Li, Shijie Wang and Yang Li

Characterization of atmospheric structures observed by a VHF MST-type radar in the troposphere over Santa Cruz, Costa Rica

Results from the first VHF profiler research radar in Costa Rica, operating at a central radar frequency of 46.6 MHz, are presented. Emphasis has been on studies of scattering layers detected in the altitude r...

Authors: Marcial Garbanzo-Salas and Wayne Hocking

Effects of adiabatic compression on thermal convection in super-Earths of various sizes

We present two-dimensional numerical models of thermal convection of a compressible fluid in the mantles of super-Earths calculated under the truncated anelastic liquid approximation to discuss how adiabatic c...

Authors: Takehiro Miyagoshi, Masanori Kameyama and Masaki Ogawa

Amino acids on witness coupons collected from the ISAS/JAXA curation facility for the assessment and quality control of the Hayabusa2 sampling procedure

The Hayabusa2 mission aims to obtain pristine samples from a near-Earth carbonaceous-type (C-type) asteroid, 162173 Ryugu, and return them to Earth. One of the scientific goals of the mission is to understand ...

Authors: Haruna Sugahara, Yoshinori Takano, Yuzuru Karouji, Kazuya Kumagai, Toru Yada, Naohiko Ohkouchi and Masanao Abe

Combination of focused ion beam (FIB) and microtome by ultrathin slice preparation for transmission electron microscopy (TEM) observation

There are growing demands for integrated study of isotopes, trace elements and crystallography of micron-sized grains observed on polished sections or scattered on surface of sample holders. However, transmiss...

Authors: Yuchen Xu, Lixin Gu, Yang Li, Bing Mo and Yangting Lin

Special issue “Akatsuki at Venus: The First Year of Scientific Operation”

Authors: Masato Nakamura, Dmitri Titov, Kevin McGouldrick, Pierre Drossart, Jean-Loup Bertaux and Huixin Liu

Initiation of a lightning search using the lightning and airglow camera onboard the Venus orbiter Akatsuki

The existence of lightning discharges in the Venus atmosphere has been controversial for more than 30 years, with many positive and negative reports published. The lightning and airglow camera (LAC) onboard th...

Authors: Yukihiro Takahashi, Mitsuteru Sato, Masataka Imai, Ralph Lorenz, Yoav Yair, Karen Aplin, Georg Fischer, Masato Nakamura, Nobuaki Ishii, Takumi Abe, Takehiko Satoh, Takeshi Imamura, Chikako Hirose, Makoto Suzuki, George L. Hashimoto, Naru Hirata…

Redistribution of Sr and rare earth elements in the matrices of CV3 carbonaceous chondrites during aqueous alteration in their parent body

We measured the abundances of Sr and rare earth elements (REEs) in the matrices of five CV3 carbonaceous chondrites: Meteorite Hills (MET) 00430, MET 01070, La Paz ice field (LAP) 02206, Asuka (A) 881317 and R...

Authors: Kaori Jogo, Motoo Ito, Tomoki Nakamura, Sachio Kobayashi and Jong Ik Lee

Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images

Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths from ultraviolet (283 and 365 nm) and near ...

Authors: Sanjay S. Limaye, Shigeto Watanabe, Atsushi Yamazaki, Manabu Yamada, Takehiko Satoh, Takao M. Sato, Masato Nakamura, Makoto Taguchi, Tetsuya Fukuhara, Takeshi Imamura, Toru Kouyama, Yeon Joo Lee, Takeshi Horinouchi, Javier Peralta, Naomoto Iwagami, George L. Hashimoto…

Mean winds at the cloud top of Venus obtained from two-wavelength UV imaging by Akatsuki

Venus is covered with thick clouds. Ultraviolet (UV) images at 0.3–0.4 microns show detailed cloud features at the cloud-top level at about 70 km, which are created by an unknown UV-absorbing substance. Images...

Authors: Takeshi Horinouchi, Toru Kouyama, Yeon Joo Lee, Shin-ya Murakami, Kazunori Ogohara, Masahiro Takagi, Takeshi Imamura, Kensuke Nakajima, Javier Peralta, Atsushi Yamazaki, Manabu Yamada and Shigeto Watanabe

Initial products of Akatsuki 1-μm camera

The status and initial products of the 1-μm camera onboard the Akatsuki mission to Venus are presented. After the successful retrial of Venus’ orbit insertion on Dec. 2015 (5 years after the failure in Dec. 20...

Authors: Naomoto Iwagami, Takeshi Sakanoi, George L. Hashimoto, Kenta Sawai, Shoko Ohtsuki, Seiko Takagi, Kazunori Uemizu, Munetaka Ueno, Shingo Kameda, Shin-ya Murakami, Masato Nakamura, Nobuaki Ishii, Takumi Abe, Takehiko Satoh, Takeshi Imamura, Chikako Hirose…

Strain localization and fabric development in polycrystalline anorthite + melt by water diffusion in an axial deformation experiment

We performed two axial deformation experiments on synthetic polycrystalline anorthite samples with a grain size of ~ 3 μm and 5 vol% Si–Al-rich glass at 900 °C, a confining pressure of 1.0 GPa, and a strain ra...

Authors: Jun-ichi Fukuda, Jun Muto and Hiroyuki Nagahama

Autonomous spectrographic system to analyse the main elements of fireballs and meteors

We present a meteor observation system based on imaging CCD cameras, wide-field optics and a diffraction grating. This system is composed of two independent spectrographs with different configurations, which a...

Authors: Francisco Ángel Espartero, Germán Martínez, Marta Frías, Francisco Simón Montes Moya and Alberto Javier Castro-Tirado

Overview of Akatsuki data products: definition of data levels, method and accuracy of geometric correction

We provide an overview of data products from observations by the Japanese Venus Climate Orbiter, Akatsuki, and describe the definition and content of each data-processing level. Levels 1 and 2 consist of non-c...

Authors: Kazunori Ogohara, Masahiro Takagi, Shin-ya Murakami, Takeshi Horinouchi, Manabu Yamada, Toru Kouyama, George L. Hashimoto, Takeshi Imamura, Yukio Yamamoto, Hiroki Kashimura, Naru Hirata, Naoki Sato, Atsushi Yamazaki, Takehiko Satoh, Naomoto Iwagami, Makoto Taguchi…

Effects of variation in coagulation and photochemistry parameters on the particle size distributions in the Venus clouds

This paper explores the effects that variation in the coalescence efficiency of the Venus cloud particles can have on the structure of the Venus cloud. It is motivated by the acknowledgment of uncertainties in...

Authors: Kevin McGouldrick

Performance of Akatsuki/IR2 in Venus orbit: the first year

The first year (December 2015 to November 2016) of IR2 after Akatsuki’s successful insertion to an elongated elliptical orbit around Venus is reported with performance evaluation and results of data acquisitio...

Authors: Takehiko Satoh, Takao M. Sato, Masato Nakamura, Yasumasa Kasaba, Munetaka Ueno, Makoto Suzuki, George L. Hashimoto, Takeshi Horinouchi, Takeshi Imamura, Atsushi Yamazaki, Takayuki Enomoto, Yuri Sakurai, Kosuke Takami, Kenta Sawai, Takashi Nakakushi, Takumi Abe…

Absolute calibration of brightness temperature of the Venus disk observed by the Longwave Infrared Camera onboard Akatsuki

The Venus Climate Orbiter Akatsuki arrived at Venus in December 2015, and the Longwave Infrared Camera (LIR) onboard the spacecraft started making observations. LIR has acquired more than 8000 images during th...

Authors: Tetsuya Fukuhara, Makoto Taguchi, Takeshi Imamura, Akane Hayashitani, Takeru Yamada, Masahiko Futaguchi, Toru Kouyama, Takao M. Sato, Mao Takamura, Naomoto Iwagami, Masato Nakamura, Makoto Suzuki, Munetaka Ueno, George L. Hashimoto, Mitsuteru Sato, Seiko Takagi…

Initial performance of the radio occultation experiment in the Venus orbiter mission Akatsuki

After the arrival of Akatsuki spacecraft of Japan Aerospace Exploration Agency at Venus in December 2015, the radio occultation experiment, termed RS (Radio Science), obtained 19 vertical profiles of the Venus...

Authors: Takeshi Imamura, Hiroki Ando, Silvia Tellmann, Martin Pätzold, Bernd Häusler, Atsushi Yamazaki, Takao M. Sato, Katsuyuki Noguchi, Yoshifumi Futaana, Janusz Oschlisniok, Sanjay Limaye, R. K. Choudhary, Yasuhiro Murata, Hiroshi Takeuchi, Chikako Hirose, Tsutomu Ichikawa…

An evaluation method of reflectance spectra to be obtained by Hayabusa2 Near-Infrared Spectrometer (NIRS3) based on laboratory measurements of carbonaceous chondrites

We conducted ground-based performance evaluation tests of the Near-Infrared Spectrometer (NIRS3) onboard Hayabusa2 spacecraft in November 2013 and from April to May 2014 and established a method for evaluating...

Authors: Moe Matsuoka, Tomoki Nakamura, Takahito Osawa, Takahiro Iwata, Kohei Kitazato, Masanao Abe, Yusuke Nakauchi, Takehiko Arai, Mutsumi Komatsu, Takahiro Hiroi, Naoya Imae, Akira Yamaguchi and Hideyasu Kojima

Volcanic activity on Io and its influence on the dynamics of the Jovian magnetosphere observed by EXCEED/Hisaki in 2015

Jupiter’s moon Io, which orbits deep inside the magnetosphere, is the most geologically active object in the solar system. Kurdalagon Patera, a volcano on Io, erupted in 2015 and became a substantial source of...

Authors: Ichiro Yoshikawa, Fumiharu Suzuki, Reina Hikida, Kazuo Yoshioka, Go Murakami, Fuminori Tsuchiya, Chihiro Tao, Atsushi Yamazaki, Tomoki Kimura, Hajime Kita, Hiromasa Nozawa and Masaki Fujimoto

Planetesimal formation by an axisymmetric radial bump of the column density of the gas in a protoplanetary disk

We investigate the effect of a radial pressure bump in a protoplanetary disk on planetesimal formation. We performed the two-dimensional numerical simulation of the dynamical interaction of solid particles and...

Authors: Isamu K. Onishi and Minoru Sekiya

Extremely long transition phase of thermal convection in the mantle of massive super-Earths

Adiabatic compression is a key factor that exerts control over thermal convection in the compressible solid mantle of super-Earths. To discuss the effects of adiabatic compression, we present a numerical model...

Authors: Takehiro Miyagoshi, Masanori Kameyama and Masaki Ogawa

The Oasis impact structure, Libya: geological characteristics from ALOS PALSAR-2 data interpretation

Optical and infrared remote sensing may provide first-order clues for the identification of potential impact structures on the Earth. Despite the free availability of at least optical image data at highest res...

Authors: Stephan van Gasselt, Jung Rack Kim, Yun-Soo Choi and Jaemyeong Kim

Special issue “Science of solar system materials examined from Hayabusa and future missions (II)”

Authors: Tatsuaki Okada, Richard P. Binzel, Harold C. Connolly Jr., Toru Yada and Keiji Ohtsuki

Evolution of the rheological structure of Mars

The evolution of Mars has been greatly influenced by temporal changes in its rheological structure, which may explain the difference in tectonics between Mars and Earth. Some previous studies have shown the rh...

Authors: Shintaro Azuma and Ikuo Katayama

Laser link experiment with the Hayabusa2 laser altimeter for in-flight alignment measurement

We report results of a laser link experiment between a laser altimeter called light detection and ranging (LIDAR) aboard Hayabusa2 and ground-based satellite laser ranging stations conducted when the spacecraf...

Authors: Hirotomo Noda, Hiroo Kunimori, Takahide Mizuno, Hiroki Senshu, Naoko Ogawa, Hiroshi Takeuchi, Chris Moore, Alex Pollard, Tomohiro Yamaguchi, Noriyuki Namiki, Teiji Kase, Takanao Saiki and Yuichi Tsuda

Tectonic evolution of northwestern Imbrium of the Moon that lasted in the Copernican Period

The formation ages of tectonic structures and their spatial distributions were studied in the northwestern Imbrium and Sinus Iridum regions using images obtained by Terrain Camera and Multiband Imager on board...

Authors: Yuko Daket, Atsushi Yamaji, Katsushi Sato, Junichi Haruyama, Tomokatsu Morota, Makiko Ohtake and Tsuneo Matsunaga

Characterization of asteroid analogues by means of emission and reflectance spectroscopy in the 1- to 100-µm spectral range

The last decades have seen a large number of missions targeting small bodies in the solar system. NASA, ESA and JAXA sent missions to different solar system small bodies (SSSB), and the Japan mission Hayabusa ...

Authors: Alessandro Maturilli, Jörn Helbert, Sabrina Ferrari, Björn Davidsson and Mario D’Amore

Thermo-optical simulation and experiment for the assessment of single, hollow, and large aperture retroreflector for lunar laser ranging

A single aperture and hollow retroreflector [corner-cube mirror (CCM)] that in principle has no internal optical path difference is a key instrument for achieving lunar laser ranging one order or more accurate...

Authors: Hiroshi Araki, Shingo Kashima, Hirotomo Noda, Hiroo Kunimori, Kouta Chiba, Hitomi Mashiko, Hiromasa Kato, Toshimichi Otsubo, Yoshiaki Matsumoto, Seiitsu Tsuruta, Kazuyoshi Asari, Hideo Hanada, Susumu Yasuda, Shin Utsunomiya and Hideo Takino

On the effect of emergence angle on emissivity spectra: application to small bodies

Dependence of laboratory-measured emissivity spectra from the emergence angle is a subject that still needs a lot of investigations to be fully understood. Most of the previous work is based on reflectance mea...

Authors: Alessandro Maturilli, Jörn Helbert, Sabrina Ferrari and Mario D’Amore

AKATSUKI returns to Venus

AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate the climate system of Venus. The orbiter was launched on May 21, 2010, and it reached Venus on December 7, 2010. Thrust was appl...

Authors: Masato Nakamura, Takeshi Imamura, Nobuaki Ishii, Takumi Abe, Yasuhiro Kawakatsu, Chikako Hirose, Takehiko Satoh, Makoto Suzuki, Munetaka Ueno, Atsushi Yamazaki, Naomoto Iwagami, Shigeto Watanabe, Makoto Taguchi, Tetsuya Fukuhara, Yukihiro Takahashi, Manabu Yamada…

Development and in-flight calibration of IR2: 2-μm camera onboard Japan’s Venus orbiter, Akatsuki

IR2, a near-infrared camera in the 2-μm region onboard Akatsuki has been developed to primarily study the middle-to-lower atmospheric dynamics of Venus as probed in the 1.74- and 2.3-μm “windows” of the

Authors: Takehiko Satoh, Masato Nakamura, Munetaka Ueno, Kazunori Uemizu, Makoto Suzuki, Takeshi Imamura, Yasumasa Kasaba, Seiji Yoshida and Masafumi Kimata

Miniature lightweight X-ray optics (MiXO) for surface elemental composition mapping of asteroids and comets

The compositions of diverse planetary bodies are of fundamental interest to planetary science, providing clues to the formation and evolutionary history of the target bodies and the solar system as a whole. Ut...

Authors: Jaesub Hong and Suzanne Romaine

Special issue “International CAWSES-II Symposium”

This special issue gathered papers from the International CAWSES-II Symposium (November 18–22, 2013 at Nagoya University, Japan). Climate and Weather of the Sun-Earth System II (CAWSES-II) is an international ...

Authors: Mamoru Yamamoto, Kazuo Shiokawa, Takuji Nakamura and Nat Gopalswamy

⁴⁰Ar/³⁹Ar and cosmic ray exposure ages of plagioclase-rich lithic fragments from Apollo 17 regolith, 78461

Argon isotopic data is used to assess the potential of low-mass samples collected by sample return missions on planetary objects (e.g., Moon, Mars, asteroids), to reveal planetary surface processes. We report ...

Authors: J. P. Das, S. L. Baldwin and J. W. Delano

Mineralogy and petrology of lunar meteorite Northwest Africa 2977 consisting of olivine cumulate gabbro including inverted pigeonite

Lunar meteorite Northwest Africa (NWA) 2977 is identified as an olivine cumulate gabbro (OC), consisting of coarse cumulate olivine crystals up to 1 mm with low-Ca and high-Ca pyroxenes, plagioclase, and inter...

Authors: Hiroshi Nagaoka, Yuzuru Karouji, Hiroshi Takeda, Timothy J. Fagan, Mitsuru Ebihara and Nobuyuki Hasebe

Recovery and validation of Mars ionospheric electron density profiles from Mariner 9

Electron density profiles from the ionosphere of Mars that were obtained by the Mariner 9 radio occultation experiment in 1971–1972 have unique scientific value because they extend to higher altitudes than com...

Authors: Paul Withers, Sarah Weiner and Nicholas Roy Ferreri

The mineralogy and space weathering of a regolith grain from 25143 Itokawa and the possibility of annealed solar wind damage

We report the results of detailed mineralogical investigations by analytical scanning and transmission electron microscopy of particle RA-QD02-0115 recovered from the surface of asteroid 25143 Itokawa. We divi...

Authors: Dennis Harries and Falko Langenhorst

X-ray absorption near edge structure spectroscopic study of Hayabusa category 3 carbonaceous particles

Analyses with a scanning transmission x-ray microscope (STXM) using x-ray absorption near edge structure (XANES) spectroscopy were applied for the molecular characterization of two kinds of carbonaceous partic...

Authors: Hikaru Yabuta, Masayuki Uesugi, Hiroshi Naraoka, Motoo Ito, A L David Kilcoyne, Scott A Sandford, Fumio Kitajima, Hajime Mita, Yoshinori Takano, Toru Yada, Yuzuru Karouji, Yukihiro Ishibashi, Tatsuaki Okada and Masanao Abe

Effect of lift force on the aerodynamics of dust grains in the protoplanetary disk

We newly introduce lift force into the aerodynamics of dust grains in a protoplanetary disk. Although many authors have investigated the effects of the drag force, gravitational force, and electric force on the d...

Authors: Masaki S Yamaguchi and Shigeo S Kimura

Mineralogy and defect microstructure of an olivine-dominated Itokawa dust particle: evidence for shock metamorphism, collisional fragmentation, and LL chondrite origin

We report here detailed analytical scanning and transmission electron microscopic investigations on an olivine-dominated dust particle (RB-QD04-0042) from the surface of asteroid 25143 Itokawa. The dust partic...

Authors: Falko Langenhorst, Dennis Harries, Kilian Pollok and Peter A van Aken

H, C, and N isotopic compositions of Hayabusa category 3 organic samples

Since isotopic ratios of H, C, and N are sensitive indicators for determining extraterrestrial organics, we have measured these isotopes of Hayabusa category 3 organic samples of RB-QD04-0047-02, RA-QD02-0120,...

Authors: Motoo Ito, Masayuki Uesugi, Hiroshi Naraoka, Hikaru Yabuta, Fumio Kitajima, Hajime Mita, Yoshinori Takano, Yuzuru Karouji, Toru Yada, Yukihiro Ishibashi, Tatsuaki Okada and Masanao Abe

Microchemical and structural evidence for space weathering in soils from asteroid Itokawa

Here we report microchemical and microstructural features indicative of space weathering in a particle returned from the surface of asteroid Itokawa by the Hayabusa mission. Space weathering features include p...

Authors: Michelle S Thompson, Roy Christoffersen, Thomas J Zega and Lindsay P Keller

Electrical conductivity of the mantle of Mars from MGS magnetic observations

Mars Global Surveyor (MGS) magnetic data were analyzed to obtain the electromagnetically induced response of the Martian mantle. The time-varying part of the MGS magnetic data analysis was obtained by removing...

Authors: François Civet and Pascal Tarits

Mineralogy and crystallography of some Itokawa particles returned by the Hayabusa asteroidal sample return mission

We studied seven Itokawa particles provided by the Japan Aerospace Exploration Agency (JAXA) as first International Announcement of Opportunity (AO) study mainly using electron and synchrotron radiation X-ray ...

Authors: Takashi Mikouchi, Mutsumi Komatsu, Kenji Hagiya, Kazumasa Ohsumi, Michael E Zolensky, Viktor Hoffmann, James Martinez, Rupert Hochleitner, Melanie Kaliwoda, Yasuko Terada, Naoto Yagi, Masaki Takata, Wataru Satake, Yuya Aoyagi, Atsushi Takenouchi, Yuzuru Karouji…