We calculate the simultaneous in situ formation of Jupiter and Saturn by the core instability mechanism considering the oligarchic growth regime for the accretion of planetesimals. We consider a density distribution for the size of planetesimals and planetesimals migration. The planets are immersed in a realistic protoplanetary disk that evolves with time. We find that, within the classical model of solar nebula, the isolated formation of Jupiter and Saturn undergoes significant change when it occurs simultaneously.

Planetary migration provides a theoretical basis for the observed diversity of exoplanetary systems. We demonstrate that dust settling - an inescapable feature of disk evolution - gives even more rapid type I migration by up to a factor of about 2 than occurs in disks with fully mixed dust. On the other hand, type II migration becomes slower by a factor of 2 due to dust settling. This even more problematic type I migration can be resolved by the presence of a dead zone; the inner, high density region of a disk which features a low level of turbulence. We show that enhanced dust settling in the dead zone leaves a dusty wall at its outer edge. Back-heating of the dead zone by this wall produces a positive radial gradient for the disk temperature, which acts as a barrier for type I migration.

We present a new formation mechanism to produce short-period Earth-like planets in the late stage of planet formation, through a collision-merger scenario. In this scenario, a planetary embryo is directly thrown into a close-in orbit after a collision with another embryo, and then the larger merged body is seized by the central star as a hot Earth-like planet.

Planetesimal formation occurs early in the evolution of a solar system, embedded in the circumstellar gas disk, and it is the crucial first step in planet formation. Their growth is difficult beyond boulder size, and likely proceeds via the accumulation of many rocks in turbulence followed by gravitational collapse - a process we are only beginning to understand. We have performed global simulations of the gas disk with embedded particles in the FLASH code. Particles and gas feel drag based on differential velocities and densities. Grains and boulders of various sizes have been investigated, from micron to km, with the goal of understanding where in the disk large planetesimals will tend to form, what sizes will result, and what size ranges of grains will be preferentially incorporated. We have so far simulated particles vertical settling and radial drift under the influence of gas drag, and their accumulations in turbulent clumps.

The purpose of the SEEDS project (PI: M. Tamura) is to conduct a direct imaging survey, searching for giant planets as well as protoplanetary/debris disks at a few to a few tens of AU regions around 500 nearby solar-type or more massive young stars with the combination of the Subaru 8.2m telescope, the new high-contrast instrument HiCIAO, and the adaptive optics system AO188. After instrument performance verification, the SEEDS survey successfully started in October 2009. We have already detected many companion candidates to be followed-up, and clear and much better detections of disks or details of known disks structures. In this contribution, we will outline our goal, current status, early results, and future instrumentation plans.

We carry out a resolution study on the fragmentation boundary of self-gravitating discs. We perform three-dimensional Smoothed Particle Hydrodynamics (SPH) simulations of discs to determine whether the critical value of the cooling timescale in units of the orbital timescale, βcrit, converges with increasing resolution. Using particle numbers ranging from 31,250 to 16 million (the highest resolution simulations to date) we do not find convergence. Instead, fragmentation occurs for longer cooling timescales as the resolution is increased. These results certainly suggest that βcrit is larger than previously thought. However, the absence of convergence also questions whether or not a critical value exists. In light of these results, we caution against using cooling timescale or gravitational stress arguments to deduce whether gravitational instability may or may not have been the formation mechanism for observed planetary systems.

With the end of answer questions as, how common are planetary systems like our own in the Universe? and What is the diversity of planetary systems that we could find in the universe?, we develop a semi-analytical model for computing planetary systems formation and consider different initial conditions for generating a large sample of planetary systems, which is analysed statistically. We explore the effects in the planetary system architecture of assuming different initial disc profiles and planetary migration rates.

The determination of the stellar parameters of M dwarfs is of prime importance in the fields of galactic, stellar and planetary astronomy. M stars are the least studied galactic component regarding their fundamental parameters. Yet, they are the most numerous stars in the galaxy and contribute to most of its total (baryonic) mass. In particular, we are interested in their metallicity in order to study the star-planet connection and to refine the planetary parameters. As a preliminary result we present a test of the metallicity calibrations of Bonfils et al. (2005), Johnson & Apps (2009), and Schlaufman & Laughlin (2010) using a new sample of 17 binaries with precise V band photometry.

Searches for planets around giants represent an essential complement to ’traditional’ surveys, because they furnish information about properties of planetary systems around stars that are the descendants of the A-F main sequence (MS) stars with masses as high as ~5 M⊙. As the stars evolve off the MS, their effective temperatures and rotation rates decrease to the point that their radial velocity variations can be measured with a few ms−1 precision. This offers an excellent opportunity to improve our understanding of the population of planets around stars that are significantly more massive than the Sun, without which it would be difficult to produce abroad, integrated picture of planet formation and evolution. Since 2001, about 30 such objects have been identified, including our five published HET detections (Niedzielski et al. 2007; Niedzielski et al. 2009a; Niedzielski et al. 2009b). Our work has produced the tightest orbit of a planet orbiting a K-giant identified so far (0.6 AU), and the first convincing evidence for a multiplanet system around such as star (Niedzielski et al. 2009a). Our most recent discoveries (Niedzielski et al. 2009b) have identified new multiplanet systems, including a very intriguing one of two brown dwarf-mass bodies orbiting a 2.8M⊙, K2 giant. This particular detection challenges the standard interpretation of the so-called brown dwarf desert known to exist in the case of solar-mass stars. Along with discoveries supplied by other groups, our work has substantially added to the emerging evidence that stellar mass positively correlates with masses of substellar companions, all the way from red dwarfs to intermediate-mass stars. We present current status and forthcoming results from the Pennsylvania-Toruń Search for Planets performed with the Hobby-Eberly Telescope (HET) since 2004.

M dwarfs constitute more than 70% of the stars in the solar neighborhood. They are cooler and smaller than Sun-like stars and have less-massive disks which suggests that planets around these stars are more likely to be Neptune-size or smaller. The transit depths and transit times of planets around M stars are large and well-matched to the Kepler temporal resolution. As a result, M stars have been of particular interest for searching for planets in both radial velocity and transit photometry surveys. We have recently started a project on searching for possible planet-hosting M stars in the publicly available data from Kepler space telescope. We have used four criteria, namely, the magnitude, proper motion, H-Ks and J-H colors, and searched for M stars in Q0 and Q1 data sets. We have been able to find 108 M stars among which 54 had not been previously identified among Kepler's targets. We discuss the details of our selection process and present the results.

Overdensity of dust with respect to the gas in the planet forming regions is a crucial prerequisite to form larger bodies and eventually planets. We use a state-of-the-art code to simulate dust evolution processes in gas-rich circumstellar discs, including the viscous gas evolution. We find significant deviations of the radial distribution of dust from that of the gas as early as 1-2Myr. These deviations are closely related to the efficiency of grain growth. Apparent discrepancies between dust and gas distributions are suggested by the current millimetre interferometer observations, and ALMA will allow us tointerpret any such discrepancies in the context of dust evolution.

One of the first stages of planet formation is the growth of small planetesimals and their accumulation into large planetesimals and planetary embryos. This early stage occurs much before the dispersal of most of the gas from the protoplanetary disk. Due to their different aerodynamic properties, planetesimals of different sizes/shapes experience different drag forces from the gas at these stage. Such differential forces produce a wind-shearing effect between close by, different size planetesimals. For any two planetesimals, a wind-shearing radius can be considered, at which the differential acceleration due to the wind becomes greater than the mutual gravitational pull between the planetesimals. We find that the wind-shearing radius could be much smaller than the gravitational shearing radius by the Sun (the Hill radius), i.e. during the gas-phase of the disk wind-shearing could play a more important role than tidal perturbations by the Sun. Here we study the wind-shearing radii for planetesimal pairs of different sizes and compare it with gravitational shearing (drag force vs. gravitational tidal forces). We then discuss the role of wind-shearing for the stability and survival of binary planetesimals, and provide stability criteria for binary planetesimals embedded in a gaseous disk.

ϵ Eridani hosts one known inner planet and an outer Kuiper belt analog. Further, Spitzer/IRS measurements indicate that warm dust is present at distances as close as a few AU from the star. Its origin is puzzling, since an “asteroid belt” that could produce this dust would be unstable because of the inner planet. We tested a hypothesis that the observed warm dust is generated by collisions in the outer belt and is transported inward by P-R drag and strong stellar winds. With numerical simulation we investigated how the dust streams from the outer ring into the inner system, and calculated the thermal emission of the dust. We show that the observed warm dust can indeed stem from the outer belt. Our models reproduce the shape and magnitude of the observed SED from mid-IR to sub-mm wavelengths, as well as the Spitzer/MIPS radial brightness profiles.

The microlensing technique has found 10 exoplanets to date and promises to discover more in the near future. While planetary transit light curves all show a familiar shape, planetary perturbations to microlensing light curves can manifest a wide variety of morphologies. We present a graphical guide that may be useful when understanding microlensing events showing planetary caustic perturbations.

Microlensing searches for planets are sensitive to small, cold exoplanets from 1–6 AU from their host stars and therefore probe an important part of parameter space. Other techniques would require many years of observations, often from space, to detect similar systems. Microlensing events can be characterised from only ground-based observations over a relatively short (≤100d) timescales. LCOGT and SUPA/St Andrews are building a robotic global network of telescopes that will be well suited to follow these events. Here we present preliminary results of the Galactic Bulge observing season 2010 March–October.

We use an improved version of the planetary evolution code described in Helled et al. (2006) to model the effect of opacity on the evolution of giant planets in the disk instability scenario. We find that changing the opacity law can cause significant changes in the evolutionary path of a protoplanet. Sufficiently high opacities cause oscillatory behavior that delays the final collapse. Peak luminosities just before collapse can exceed 10−5L⊙.

We present a mechanism for the formation of massive gas giants on wide orbits via disk fragmentation in the embedded phase of star formation. In this phase, protostellar disks undergo radial pulsations which lead to periodic disk compressions and formation of massive fragments on radial distances of the order of 50–300 AU. The fragments that form during the last episode of disk compression near the end of the embedded phase, when torque from spiral arms become weaker, may survive and mature into massive gas giants. This phenomenon can explain the existence of massive exoplanets on wide orbits is such systems as Fomalhaut and HR 8799.

The four new transit light curves of WASP-12b are analyzed by using MCMC simulation so as to derive the system parameters. If the apsidal precession exists in the orbit of WASP-12b, according to the theory of Gimenez & Bastero (1995), the rate of precession is estimated as 0.0076 degrees per cycle in the case of orbit with an inclination of 90°.

The algorithm of spectral energy distribution (SED) calculations for protoplanetary disks and central objects is created. The results of SEDs calculations for substars with protoplanetary disks that have a different ages and inclinational angles are discussed.

We give a preliminary report on a multi-wavelength study of specular reflections from the oceans and clouds of Earth. We use space-borne observations from a distance sufficient to ensure that light rays reflected from all parts of Earth are closely parallel, as they will be when studying exoplanets. We find that the glint properties of Earth in this far-field vantage point are surprising - in the sense that some of the brightest reflections are not from conventional ocean-glints, but appear to arise from cirrus cloud crystals. The Earth observations discussed here were acquired with the High Resolution Instrument (HRI) - a 0.3 m f/35 telescope on the Deep Impact (DI) spacecraft during the Extrasolar Planet Observation and Characterization (EPOCh) investigation.