Related papers: Successive common envelope events from multiple pl…
Most stars form in star clusters and stellar associated. To understand the roles of star cluster environments in shaping the dynamical evolution of planetary systems, we carry out direct $N$-body simulations of four planetary systems models…
We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of…
We model explosions driven by the coalescence of a black hole or neutron star with the core of its massive-star companion. Upon entering a common envelope phase, a compact object may spiral all the way to the core. The concurrent release of…
Recent studies have shown that the radii and masses of adjacent planets within a planetary system are correlated. It is unknown how this 'peas-in-a-pod' phenomenon originates, whether it is in place at birth or requires evolution, and…
The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level…
Recent discoveries of strongly misaligned transiting exoplanets pose a challenge to the established planet formation theory which assumes planetary systems to form and evolve in isolation. However, the fact that the majority of stars…
We evolve stellar models to study the common envelope (CE) interaction of an early asymptotic giant branch star of initial mass $5\,\rm M_{\odot}$ with a companion star of mass ranging from $0.1$ to $2\,\rm M_{\odot}$. We model the CE as a…
As of today over 40 planetary systems have been discovered in binary star systems. In all cases the configuration appears to be circumstellar, where the planets orbit around one of the stars, the secondary acting as a perturber. The…
Planetary systems with more than two bodies will experience orbital crossings at a time related to the initial orbital separations of the planets. After a crossing, the system enters a period of chaotic evolution ending in the reshaping of…
Stellar coronal mass ejections (CMEs) are a growing research field, especially during the past decade. The large number of so far detected exoplanets raises the open question for the CME activity of stars, as CMEs may strongly affect…
We conduct gas and dust hydrodynamical simulations of protoplanetary discs with one and two embedded planets to determine the impact that a second planet located further out in the disc has on the potential for subsequent planet formation…
By analysing and modelling the change in the abundance ratio of $^{12}$C/$^{13}$C and $^{16}$O/$^{17}$O on the surface of the lower mass star of a binary during the common-envelope (CE) phase of evolution, we propose a simple observational…
I consider a flow structure by which main sequence companions that enter a common envelope evolution (CEE) with giant stars might launch jets even when the accreted gas has a sub-Keplerian specific angular momentum. I first show that after…
Dynamical evolution within planetary systems can cause planets to be engulfed by their host stars. Following engulfment, the stellar photosphere abundance pattern will reflect accretion of rocky material from planets. Multi-star systems are…
Planets form in disks around young stars. Interactions with these disks cause them to migrate and thus affect their final orbital periods. We suggest that the connection between planets and disks may be deeper and involve a symbiotic…
The discovery of planets around massive stars is important for understanding how planet formation and evolution is conditioned by different stellar environments. However, current planetary search surveys have failed to detect planets around…
I construct the class of supernovae and supernova progenitors that result from fatal common envelope evolution (CEE). The fatal CEE progenitors are stellar binary systems where a companion spirals-in inside the envelope of a giant star and…
The morphology of bipolar planetary nebulae (PNe) can be attributed to interactions between a fast wind from the central engine and dense toroidal shaped ejecta left over from common envelope (CE) evolution. Here we use the 3-D hydrodynamic…
We have developed a new method for calculating common envelope (CE) events based on explicit consideration of the donor star's structural response to adiabatic mass loss. In contrast to existing CE prescriptions, which specify a priori the…
The {\it Kepler} mission has detected thousands of planetary systems with 1-7 transiting planets packed within 0.7~au from their host stars. There is an apparent excess of single-transit planet systems that cannot be explained by transit…