The discovery of now about 20 extrasolar planets orbiting solar-type stars with properties quite different from those in our Solar System has raised many questions about the formation and evolution of planets. The tidal interaction between the planet and the surrounding disk determines the orbital properties and the mass of the planet. We have performed numerical computations of planets embedde...

For the past two years we have been developing PLaneT, a package manager built into PLT Scheme’s module system that simplifies program development by doing away with the distinction between installed and uninstalled packages. In this paper we explain how PLaneT works and the rationales behind our major design choices, focusing particularly on our decision to integrate PLaneT into PLT Scheme and...

We investigate the motion of a particle around a low mass planet embedded in a non-turbulent gaseous disk. We take into account the effect of the gas structure that is modified by the gravitational interaction between the planet. We derive an analytic formula that describes the change of the semi-major axis of the particle due to the encounter with the planet using local approximation in distan...

The exo-solar planet HD 80606b has a highly eccentric (e = 0.93) and tight (a = 0.47 AU) orbit. We study how it might arrive at such an orbit and how it has avoided being tidally circularized until now. The presence of a stellar companion to the host star suggests the possibility that the Kozai mechanism and tidal dissipation combined to draw the planet inward well after it formed: Kozai oscill...

The eccentricity evolution of multiple planet systems can provide valuable constraints on planet formation models. Unfortunately, the inevitable uncertainties in the current orbital elements can lead to significant ambiguities in the nature of the secular evolution. Integrating any single set of orbital elements inadequately describes the full range of secular evolutions consistent with current...

We present the results of a uniform, high-precision spectroscopic metallicity study of 136 G-type stars from the Anglo-Australian Planet Search, 20 of which are known to harbour extrasolar planets (as at July 2005). Abundances in Fe, C, Na, Al, Si, Ca, Ti and Ni are presented, along with Strömgen photometric metallicities. This study is one of several recent studies examining the metallicities ...

The detection of absorption features in spectra of 51 Peg obtained during transit of its planet would provide a first clue on the physical nature of the planet. We have searched for signatures of an exosphere of the planet orbiting 51 Peg in the wavelength range from 2.39 μm to 3.5 μm and from 4.55 μm to 4.74 μm using SWS on ISO. Careful comparison of spectra taken during the transit of the pla...

The recent discovery of a planetary transit in the star HD 209458, and the subsequent highly precise observation of the transit lightcurve with HST, is encouraging to search for any phenomena that might induce small changes in the lightcurve. Here we consider the effect of the quadrupole moment of the parent star, and of a possible second planet perturbing the orbit of the transiting planet. Bo...

1 Based on observations obtained at Lick Observatory, operated by the University of California, and at the Whipple Observatory, operated by the Smithsonian Astrophysical Observatory. ABSTRACT The bright F8 V star Andromedae was previously reported to have a 4.6 day Doppler velocity periodicity, consistent with a Jupiter{mass companion orbiting at 0.059 AU. Follow{up observations by both the Lic...

In 1981, β Pictoris showed strong and rapid photometric variations that were attributed to the transit of a giant comet or a planet orbiting at several AUs. Recently, a candidate planet has been identified by imagery in the circumstellar disk of β Pictoris. This planet, named β Pic b, is observed at a projected distance of 8 AU from the central star. It is therefore a plausible candidate for th...