Creating retrogradely orbiting planets by prograde stellar fly-bys

Two Earth - sized planets orbiting

Three planets orbiting Wolf 1061

We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M⊕ minimum-mass planet with an orbital period P = 4.888 d (Wolf 1061b), a 4.25 M⊕ minimum-mass planet with orbital period P = 17.867 d (Wolf 1061c), and a likely 5.21 M⊕ minimum-mass planet with orbital period P = 67.274 d (Wolf 1061d). All of the planets are of sufficiently low mass...

Stellar Collisions and Pulsar Planets

I describe models for the formation of planetary systems surrounding the remnants of stellar mergers and collisions. I focus primarily on models for the viscous evolution of disks suitable for the formation of the planets surrounding the pulsar B1257+12. I show that the adaptation of models for traditional protoplanetary disks which invoke quiescent or ‘dead’ zones are quite successful in produ...

Transit Lightcurves of Extrasolar Planets Orbiting Rapidly-Rotating Stars

Main-sequence stars earlier than spectral type ∼ F6 or so are expected to rotate rapidly due to their radiative exteriors. This rapid rotation leads to an oblate stellar figure. It also induces the photosphere to be hotter (by up to several thousand Kelvin) at the pole than at the equator as a result of a process called gravity darkening that was first predicted by von Zeipel (1924). Transits o...

Limits on Planets Orbiting Massive Stars from Radio Pulsar Timing

\Vhen a,massive star collapses to a neutron star, rapidly losing over half its mass in a symmetric supernova explosion, any planets orbiting the star will be unbound. ]Iowever, to explain the observed space velocity and binary fraction of radio pulsars, an asymmetric kick must be given to the neutron star at birth. Occasionally, this kick will prevent the resulting pulsar-planet system from unb...