159 citations · 617 across the 16 of their papers we have counts for
16 papers
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…
Architectures of planetary systems formed by pebble accretion
Ryuji Morishima
In models of planetary accretion, pebbles form by dust coagulation and rapidly migrate toward the central star. Planetesimals may continuously form from pebbles over the age of the…
Numerical Simulations of Saturn's B Ring: Granular Friction as a Mediator between Self-Gravity and Viscous Overstability
Ronald-Louis Ballouz, Derek C. Richardson, Ryuji Morishima
We study the B ring's complex optical depth structure. The source of this structure may be the complex dynamics of the Keplerian shear and the self-gravity of the ring particles. T…
Seasonal variation of radial brightness contrast of Saturn's rings viewed in mid-infrared by Subaru/COMICS
Hideaki Fujiwara, Ryuji Morishima, Takuya Fujiyoshi +1
Aims. To investigate the mid-infrared (MIR) characteristics of Saturn's rings. Methods. We collected and analyzed MIR high spatial resolution images of Saturn's rings obtained in J…
Onset of oligarchic growth and implication for accretion histories of dwarf planets
Ryuji Morishima
We investigate planetary accretion that starts from equal-mass planetesimals using an analytic theory and numerical simulations. We particularly focus on how the planetary mass $M_…
A particle-based hybrid code for planet formation
Ryuji Morishima
We introduce a new particle-based hybrid code for planetary accretion. The code uses an -body routine for interactions with planetary embryos while it can handle a large number…
Incomplete cooling down of Saturn's A ring at solar equinox: Implication for seasonal thermal inertia and internal structure of ring particles
Ryuji Morishima, Linda Spilker, Shawn Brooks +2
At the solar equinox in August 2009, the Composite Infrared Spectrometer (CIRS) onboard Cassini showed the lowest Saturn's ring temperatures ever observed. Detailed radiative trans…
Terrestrial Planet Formation at Home and Abroad
Sean N. Raymond, Eiichiro Kokubo, Alessandro Morbidelli +2
We review the state of the field of terrestrial planet formation with the goal of understanding the formation of the inner Solar System and low-mass exoplanets. We review the dynam…
N-body simulations of oligarchic growth of Mars: Implications for Hf-W chronology
Ryuji Morishima, Gregor Golabek, Henri Samuel
Dauphas and Pourmand (2011) [Nature 473, 489--492] estimated the accretion timescale of Mars to be 1.8 Myr from the W isotopes of martian meteorites. This timescal…
Regolith grain sizes of Saturn's rings inferred from Cassini-CIRS far-infrared spectra
Ryuji Morishima, Scott G. Edgington, Linda Spilker
We analyze far-infrared (10-650 cm) emissivity spectra of Saturn's main rings obtained by the Cassini Composite Infrared Spectrometer (CIRS). In modeling of the spectra, the…
A multilayer model for thermal infrared emission of Saturn's rings. III: Thermal inertia inferred from Cassini CIRS
Ryuji Morishima, Linda Spilker, Keiji Ohtsuki
The thermal inertia values of Saturn's main rings (the A, B, and C rings and the Cassini division) are derived by applying our thermal model to azimuthally scanned spectra taken by…
Gap opening beyond dead zones by photoevaporation
Ryuji Morishima
We propose a new hypothesis for the origin of protoplanetary discs with large inner holes (or gaps), so-called transition discs. Our gas disc model takes into account layered accre…
How common are Earth-Moon planetary systems?
Sebastian Elser, Ben Moore, Joachim Stadel +1
The Earth's comparatively massive moon, formed via a giant impact on the proto-Earth, has played an important role in the development of life on our planet, both in the history and…
From planetesimals to terrestrial planets: N-body simulations including the effects of nebular gas and giant planets
Ryuji Morishima, Joachim Stadel, Ben Moore
We present results from a suite of N-body simulations that follow the accretion history of the terrestrial planets using a new parallel treecode that we have developed. We initiall…
Formation and accretion history of terrestrial planets from runaway growth through to late time: implications for orbital eccentricity
Ryuji Morishima, Max W. Schmidt, Joachim Stadel +1
Remnant planetesimals might have played an important role in reducing the orbital eccentricities of the terrestrial planets after their formation via giant impacts. However, the po…
Stability of Terrestrial Planets in the Habitable Zone of Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208
N. Asghari, C. Broeg, L. Carone +37
We have undertaken a thorough dynamical investigation of five extrasolar planetary systems using extensive numerical experiments. The systems Gl 777 A, HD 72659, Gl 614, 47 Uma and…