Publications (36)
Towards a deterministic model of planetary formation. III. Mass distribution of short-period planets around stars of various masses
S. Ida, D. N. C. Lin
The origin of a recently discovered close-in Neptune-mass planet around GJ436 poses a challenge to the current theories of planet formation. Based on the sequential accretion hypot…
On the various origins of close-in extrasolar planets
S. Marchi, S. Ortolani, M. Nagasawa +1
The extrasolar planets (EPs) so far detected are very different to the planets in our own Solar System. Many of them have Jupiter-like masses and close-in orbits (the so-called hot…
Spatial Structure and Coherent Motion in Dense Planetary Rings Induced by Self-Gravitational Instability
H. Daisaka, S. Ida
We investigate the formation of spatial structure in dense, self-gravitating particle systems such as Saturn's B-ring through local -body simulations to clarify the intrinsic ph…
Orbital Evolution of Planets around Intermediate-Mass Giants
M. Kunitomo, M. Ikoma, B. Sato +2
Around low- and intermediate-mass (1.5-3 M_sun) red giants, no planets have been found inside 0.6 AU. Such a paucity is not seen in the case of 1 M_sun main sequence stars. In this…
Diverse outcomes of planet formation and composition around low-mass stars and brown dwarfs
Y. Miguel, A. Cridland, C. W. Ormel +2
The detection of Earth-size exoplanets around low-mass stars -- in stars such as Proxima Centauri and TRAPPIST-1 -- provide an exceptional chance to improve our understanding of th…
Trapping low-mass planets at the inner edge of the protostellar disc
R. Brasser, S. Matsumura, T. Muto +1
The formation of multiple close-in low-mass exoplanets is still a mystery. The challenge is to build a system wherein the outermost planet is beyond 0.2 AU from the star. Here we i…
The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 With a Large Dense Core
B. Sato, D. A. Fischer, G. W. Henry +18
Doppler measurements from Subaru and Keck have revealed radial velocity variations in the V=8.15, G0IV star HD 149026 consistent with a Saturn-Mass planet in a 2.8766 day orbit. Ph…
On the Origin of HD149026b
M. Ikoma, T. Guillot, H. Genda +2
The high density of the close-in extrasolar planet HD149026b suggests the presence of a huge core in the planet, which challenges planet formation theory. We first derive constrain…
The formation and retention of gas giant planets around stars with a range of metallicities
S. Ida, D. N. C. Lin
The apparent dependence of detection frequency of extrasolar planets on the metallicity of their host stars is investigated with Monte Carlo simulations using a deterministic core-…
The Signature of the Ice Line and Modest Type I Migration in the Observed Exoplanet Mass-Semimajor Axis Distribution
Kevin C. Schlaufman, D. N. C. Lin, S. Ida
Existing exoplanet radial velocity surveys are complete in the planetary mass-semimajor axis (Mp-a) plane over the range 0.1 AU < a < 2.0 AU where Mp >~ 100 M_Earth. We marginalize…
Modification of Angular Velocity by Inhomogeneous MRI Growth in Protoplanetary Disks
M. T. Kato, K. Nakamura, R. Tandokoro +2
We have investigated evolution of magneto-rotational instability (MRI) in protoplanetary disks that have radially non-uniform magnetic field such that stable and unstable regions c…
Evolution of the Velocity Dispersion of Self-Gravitating Particles in Disc Potentials
K. Shiidsuka, S. Ida
The ratio of the vertical velocity dispersion to radial one (sigma_z / sigma_R) of self-gravitating bodies in various disc potentials is investigated through two different numerica…
Planet Engulfment by ~1.5-3 Solar-Mass Red Giants
M. Kunitomo, M. Ikoma, B. Sato +2
Recent radial-velocity surveys for GK clump giants have revealed that planets also exist around ~1.5-3 Msun stars. However, no planets have been found inside 0.6 AU around clump gi…
Toward a Deterministic Model of Planetary Formation VI: Dynamical Interaction and Coagulation of Multiple Rocky Embryos and Super-Earth Systems around Solar Type Stars
S. Ida, D. N. C. Lin
Radial velocity and transit surveys indicate that solar-type stars bear super-Earths, with mass and period up to ~ 20 M_E and a few months, are more common than those with Jupiter-…
On gas drag in a circular binary system
P. Ciecielag, S. Ida, A. Gawryszczak +1
We investigate both analytically and numerically the motion of massless particles orbiting primary star in a close circular binary system with particular focus on the gas drag effe…
Evidence for early stellar encounters in the orbital distribution of Edgeworth-Kuiper Belt objects
S. Ida, J. D. Larwood, A. Burkert
We have investigated effects of early stellar encounters on a protoplanetary disk (planetesimal disk) and found that they can explain the high eccentricities and inclinations obser…
Formation of Hot Planets by a combination of planet scattering, tidal circularization, and Kozai mechanism
M. Nagasawa, S. Ida, T. Bessho
We have investigated the formation of close-in extrasolar giant planets through a coupling effect of mutual scattering, Kozai mechanism, and tidal circularization, by orbital integ…
Spinning up planetary bodies by pebble accretion
R. G. Visser, C. W. Ormel, C. Dominik +1
Most major planetary bodies in the solar system rotate in the same direction as their orbital motion: their spin is prograde. Theoretical studies to explain the direction as well a…
Merging Criteria for Giant Impacts of Protoplanets
H. Genda, E. Kokubo, S. Ida
At the final stage of terrestrial planet formation, known as the giant impact stage, a few tens of Mars-sized protoplanets collide with one another to form terrestrial planets. Alm…
The SPICA coronagraphic instrument (SCI) for the study of exoplanets
K. Enya, T. Kotani, K. Haze +39
We present the SPICA Coronagraphic Instrument (SCI), which has been designed for a concentrated study of extra-solar planets (exoplanets). SPICA mission provides us with a unique o…
Orbital Circularization of a Planet Accreting Disk Gas: Formation of Distant Jupiters in Circular Orbits based on Core Accretion Model
A. Kikuchi, A. Higuchi, S. Ida
Recently, gas giant planets in nearly circular orbits with large semimajor axes ( 30--1000AU) have been detected by direct imaging. We have investigated orbital evolution i…
Late veneer and late accretion to the terrestrial planets
R. Brasser, S. J. Mojzsis, S. C. Werner +2
It is generally accepted that silicate-metal (`rocky') planet formation relies on coagulation from a mixture of sub-Mars sized planetary embryos and (smaller) planetesimals that dy…
Extrasolar Binary Planets I: Formation by tidal capture during planet-planet scattering
H. Ochiai, M. Nagasawa, S. Ida
We have investigated i) the formation of gravitationally bounded pairs of gas-giant planets (which we call "binary planets") from capturing each other through planet-planet dynamic…
Eccentricity Evolution of Extrasolar Multiple Planetary Systems due to the Depletion of Nascent Protostellar Disks
M. Nagasawa, D. N. C. Lin, S. Ida
Most extrasolar planets are observed to have eccentricities much larger than those in the solar system. Some of these planets have sibling planets, with comparable masses, orbiting…
A dynamical study on the habitability of terrestrial exoplanets II: The super Earth HD 40307 g
R. Brasser, S. Ida, E. Kokubo
HARPS and it Kepler results indicate that half of solar-type stars host planets with periods P<100 d and masses M < 30 M_E. These super Earth systems are compact and dynamically co…
Extrasolar Binary Planets II: Detectability by Transit Observations
K. M. Lewis, H. Ochiai, M. Nagasawa +1
We discuss the detectability of gravitationally bounded pairs of gas-giant planets (which we call "binary planets") in extrasolar planetary systems that are formed through orbital…
Effect of turbulence on collisions of dust particles with planetesimals in protoplanetary disks
H. Homann, T. Guillot, J. Bec +3
Planetesimals in gaseous protoplanetary disks may grow by collecting dust particles. Hydrodynamical studies show that small particles generally avoid collisions with the planetesim…
A dynamical study on the habitability of terrestrial exoplanets I: Tidally evolved planet-satellite pairs
R. Brasser, S. Ida, E. Kokubo
We investigate the obliquity and spin period of Earth-Moon like systems after 4.5 Gyr of tidal evolution with various satellite masses and initial planetary obliquity and discuss t…
A Population of Very-Hot Super-Earths in Multiple-Planet Systems Should be Uncovered by Kepler
Kevin C. Schlaufman, D. N. C. Lin, S. Ida
We simulate a Kepler-like observation of a theoretical exoplanet population and we show that the observed orbital period distribution of the Kepler giant planet candidates is best…
Analysis of terrestrial planet formation by the Grand Tack model: System architecture and tack location
R. Brasser, S. Matsumura, S. Ida +2
The Grand Tack model of terrestrial planet formation has emerged in recent years as the premier scenario used to account for several observed features of the inner solar system. It…
Towards a Deterministic Model of Planetary Formation I: a Desert in the Mass and Semi Major Axis Distributions of Extra Solar Planets
S. Ida, D. N. C. Lin
We examine the accretion of cores of giant planets from planetesimals, gas accretion onto the cores, and their orbital migration. We adopt a working model for nascent protostellar…
Planet Population Synthesis
W. Benz, S. Ida, Y. Alibert +2
With the increasing number of exoplanets discovered, statistical properties of the population as a whole become unique constraints on planet formation models provided a link betwee…
Planet formation, orbital evolution and planet-star tidal interaction
D. N. C. Lin, J. C. B. Papaloizou, G. Bryden +2
We consider several processes operating during the late stages of planet formation that can affect observed orbital elements. Disk-planet interactions, tidal interactions with the…
A Hot Saturn Planet Orbiting HD 88133, from the N2K Consortium
D. A. Fischer, G. Laughlin, R. P. Butler +20
The N2K consortium is carrying out a distributed observing campaign with the Keck, Magellan and Subaru telescopes, as well as the automatic photometric telescopes of Fairborn Obser…
The cool and distant formation of Mars
R. Brasser, S. J. Mojzsis, S. Matsumura +1
With approximately one ninth of Earth's mass, Mars is widely considered to be a stranded planetary embryo that never became a fully-grown planet. A currently popular planet formati…
Toward a Deterministic Model of Planetary Formation VII: Eccentricity Distribution of Gas Giants
S. Ida, D. N. C. Lin, M. Nagasawa
The ubiquity of planets and diversity of planetary systems reveal planet formation encompass many complex and competing processes. In this series of papers, we develop and upgrade…