Related papers: Detecting Planets in Planetary Nebulae
A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are…
The Einstein rings and proper motions of nearby stars tend to be large. Thus, every year some foreground stars within a few hundred parsecs of Earth induce gravitational lensing events in background stars. In some of these cases, the events…
Planetary nebulae (PN) represent the evolutionary fate of the asymptotic giant branch (AGB) stellar envelopes, thus are ideally suited to study the chemical impact of AGB stars. Stellar evolution predict elemental enrichment through the AGB…
Planetary nebulae are traditionally considered to represent the final evolutionary stage of all intermediate-mass stars ($\sim$0.7-8Msol). Recent evidence seems to contradict this picture. In particular, since the launch of the Hubble Space…
I review some open questions and other aspects concerning the shaping of planetary nebulae (PNs) and related objects. I attribute the non-spherical structures of PNs to binary companions, stellar or substellar. I emphasize the role of jets…
Two-dimensional hydrodynamical simulations are presented from the formation up to the late evolution of planetary nebula, for 6 different stellar models from 1 to 5 Mo. The hydrodynamical models use stellar evolution calculations as inner…
The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband…
Given the tendency of planets to form in multiples, and the observational evidence in support of the existence of potential planet-hosting stars in binaries or clusters, it is expected that extrasolar terrestrial planes are more likely to…
Stars formed in clusters can encounter other stars at close distances. In typical open clusters in the Solar neighbourhood containing hundreds or thousands of member stars, ten to twenty per cent of Solar-mass member stars are expected to…
Context: In recent years mid- and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these…
The majority of stars form in star clusters and many are thought to have planetary companions. We demonstrate that multi-planet systems are prone to instabilities as a result of frequent stellar encounters in these star clusters much more…
Young stars are mostly found in dense stellar environments, and even our own Solar system may have formed in a star cluster. Here, we numerically explore the evolution of planetary systems similar to our own Solar system in star clusters.…
This paper discusses the location of a sample of planetary nebulae on the HR diagram. We determine the internal velocity fields of 14 planetary nebulae from high-resolution echelle spectroscopy, with the help of photoionization models. The…
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 instability followed by planet-planet dynamical tides during…
The kinematic and dynamical properties of galaxy stellar halos are difficult to measure because of the faint surface brightness that characterizes these regions. Spiral galaxies can be probed using the radio HI emission; on the contrary,…
Thousands of confirmed and candidate exoplanets have been identified in recent years. Consequently, theoretical research on the formation and dynamical evolution of planetary systems has seen a boost, and the processes of planet-planet…
Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The…
The role of planetary nebulae as probes for the galactic chemical evolution is reviewed. Their abundances throughout the Galaxy are discussed for key elements, in particular oxygen and other alpha elements. The abundance distribution…
Planetary systems formed in clusters may be subject to stellar encounter flybys. Here we create a diverse range of representative planetary systems with different orbital scales and planets' masses and examine encounters between them in a…
During the past 20 years, the idea that non-spherical planetary nebulae (PN) may need a binary or planetary interaction to be shaped was discussed by various authors. It is now generally agreed that the varied morphologies of PN cannot be…