36 citations · 159 across the 14 of their papers we have counts for
14 papers
Bundle adjustment of Hayabusa2's ONC images and controlled color mosaic map of Ryugu
Naoyuki Hirata, Eri Tatsumi, Mayumi Ichikawa +2
JAXA's Hayabusa2 mission successfully returned samples from the asteroid Ryugu in December 2020. It executed two touchdowns to collect the surface and subsurface materials, one clo…
Secondary cratering from Rheasilvia as the possible origin of Vesta's equatorial troughs
Naoyuki Hirata
Asteroid 4 Vesta has a set of parallel troughs aligned with its equator. Although previous evaluations suggest that it is of shock fracturing tectonic origin, we propose that the e…
Particle deposition on the saturnian satellites from ephemeral cryovolcanism on Enceladus
Naoyuki Hirata, Hideaki Miyamoto, Adam P. Showman
The geologically active south pole of Enceladus generates a plume of micron-sized particles, which likely form Saturn's tenuous E-ring extending from the orbit of Mimas to Titan. I…
Timing of the faulting on the Wispy Terrain of Dione based on stratigraphic relationships with impact craters
Naoyuki Hirata
The trailing hemisphere of Dione is characterized by the Wispy Terrain, where it exhibits a hemispheric-scale network of extensional tectonic faults superposed on the moon's crater…
Rayed craters on Dione: Implication for the dominant surface alteration process
Naoyuki Hirata, Hideaki Miyamoto
From recently-acquired, high-resolution images obtained by the Cassini spacecraft, we examine the patterns and spatial distributions of rayed craters on Dione. We identify 29 rayed…
The spatial distribution of impact craters on Ryugu
Naoyuki Hirata, Tomokatsu Morota, Yuichiro Cho +40
Asteroid 162173 Ryugu has numerous craters. The initial measurement of impact craters on Ryugu, by Sugita et al. (2019), is based on Hayabusa2 ONC images obtained during the first…
Ejecta emplacement as the possible origin of Ryugu's equatorial ridge
Ren Ikeya, Naoyuki Hirata
The Japanese spacecraft Hayabusa 2 visited the asteroid (162173) Ryugu and provided many high-resolution images of its surface, revealing that Ryugu has a spinning-top shape with a…
Ejecta distribution from impact craters on Ryugu: possible origin of the bluer units
Naoyuki Hirata, Ren Ikeya
Asteroid (162173) Ryugu was the first spinning-top-shaped asteroid to be closely approached by a probe, the Hayabusa2 spacecraft, which sent numerous high-resolution images of Ryug…
Rotational effect as the possible cause of the east-west asymmetric crater rims on Ryugu observed by LIDAR data
Naoyuki Hirata, Noriyuki Namiki, Fumi Yoshida +13
Asteroid 162173 Ryugu is a rubble-pile asteroid, whose top-shape is compatible with models of deformation by spin up. Rims of major craters on Ryugu have an east-west asymmetric pr…
A global system of furrows on Ganymede indicative of their creation in a single impact event
Naoyuki Hirata, Ryo Suetsugu, Keiji Ohtsuki
Furrows are a concentric system of tectonic troughs, and are the oldest recognizable surface feature on Ganymede. We analyzed the distribution of furrows utilizing Voyager and Gali…
Disruption of Saturn's ring particles by thermal stress
Naoyuki Hirata, Ryuji Morishima, Keiji Ohtsuki +1
Spacecraft and ground-based observations show that the main rings of Saturn lack particles larger than 10 m. Tidal or collisional destruction of satellites/comets have been propose…
Dust release from cold ring particles as a mechanism of spoke formation in Saturn's rings
Naoyuki Hirata, Hiroshi Kimura, Keiji Ohtsukia
Spokes in Saturn's rings are radially-extended structures consisting of dust grains. Although spacecraft and space telescope observations have revealed various detailed features of…
Electrostatic Dust Ejection From Asteroid (3200) Phaethon With the Aid of Mobile Alkali Ions at Perihelion
Hiroshi Kimura, Katsuhito Ohtsuka, Shota Kikuchi +12
The asteroid (3200) Phaethon is known to be the parent body of the Geminids, although meteor showers are commonly associated with the activity of periodic comets. What is most pecu…
The Western Bulge of 162173 Ryugu Formed as a Result of a Rotationally Driven Deformation Process
Masatoshi Hirabayashi, Eri Tatsumi, Hideaki Miyamoto +26
162173 Ryugu, the target of Hayabusa2, has a round shape with an equatorial ridge, which is known as a spinning top-shape. A strong centrifugal force is a likely contributor to Ryu…