ﻻ يوجد ملخص باللغة العربية
Close-in exoplanets interact with their host stars gravitationally as well as via their magnetized plasma outflows. The rich dynamics that arises may result in distinct observable features. Our objective is to study and classify the morphology of the different types of interaction that can take place between a giant close-in planet (a Hot Jupiter) and its host star, based on the physical parameters that characterize the system. We perform 3D magnetohydrodynamic numerical simulations to model the star--planet interaction, incorporating a star, a Hot Jupiter, and realistic stellar and planetary outflows. We explore a wide range of parameters and analyze the flow structures and magnetic topologies that develop. Our study suggests the classification of star--planet interactions into four general types, based on the relative magnitudes of three characteristic length scales that quantify the effects of the planetary magnetic field, the planetary outflow, and the stellar gravitational field in the interaction region. We describe the dynamics of these interactions and the flow structures that they give rise to, which include bow shocks, cometary-type tails, and inspiraling accretion streams. We point out the distinguishing features of each of the classified cases and discuss some of their observationally relevant properties. The magnetized interactions of star--planet systems can be categorized, and their general morphologies predicted, based on a set of basic stellar, planetary, and orbital parameters.
Expanding nebulae are produced by mass loss from stars, especially during late stages of evolution. Multi-dimensional simulation of these nebulae requires high resolution near the star and permits resolution that decreases with distance from the star
Much effort has been invested in recent years, both observationally and theoretically, to understand the interacting processes taking place in planetary systems consisting of a hot Jupiter orbiting its star within 10 stellar radii. Several independen
Evidence of star-planet interactions in the form of planet-modulated chromospheric emission has been noted for a number of hot Jupiters. Magnetic star-planet interactions involve the release of energy stored in the stellar and planetary magnetic fiel
Stars and their exoplanets evolve together. Depending on the physical characteristics of these systems, such as age, orbital distance and activity of the host stars, certain types of star-exoplanet interactions can dominate during given phases of the
We briefly introduce the VLBI maser astrometric analysis of IRAS 18043-2116 and IRAS 18113-2503, two remarkable and unusual water fountains with spectacular bipolar bow shocks in their high-speed collimated jet-driven outflows. The 22 GHz H2O maser s