Related papers: Circumstellar rings, flat and flaring discs
We have performed a high mass and force resolution simulation of an idealized galaxy forming from dissipational collapse of gas embedded in a spherical dark matter halo. The simulation includes star formation and effects of stellar…
Rotation curves of spiral galaxies are the major tool for determining the distribution of mass in spiral galaxies. They provide fundamental information for understanding the dynamics, evolution and formation of spiral galaxies. We describe…
The star formation and the subsequent metallic enrichment of spiral galaxies, occurring at the early phases of their evolution, produce emission lines whose contribution may change the colors of these objects. We have computed this…
A new type of peculiarity -- a splitting or asymmetry of strong absorption lines, is found in the optical spectra of selected post-AGB stars with C-rich circumstellar envelopes. The effect is maximal in BaII lines whose profile is split…
Massive stars form in clusters within self-gravitating molecular clouds. The size scale of these clusters is sufficiently large that non-thermal, or turbulent, motions of the gas must be taken into account when considering their formation.…
Many early-type galaxies are detected at 24 to 160 micron but the emission is usually dominated by an AGN or heating from the evolved stellar population. Here we present MIPS observations of a sample of elliptical and lenticular galaxies…
The demographic of circumstellar disks, the birthplaces of planets, is diverse and rich in disks featuring rings, gaps, spirals, filaments, and arcs. Many studies revealing these disk structures have focused on objects around single stars…
During the late stages of giant planet formation, protoplanets are surrounded by a circumplanetary disk and an infalling envelope of gas and dust. For systems with sufficient cooling, material entering the sphere of influence of the planet…
The study of the internal structure of star clusters provides important clues concerning their formation mechanism and dynamical evolution. There are both observational and numerical evidences indicating that open clusters evolve from an…
At the present epoch, clusters of galaxies are known to be a hostile environment for emission-line galaxies, which are more commonly found in low density regions outside of clusters. In contrast, going to higher redshifts the population of…
To constrain the nature of the very first stars, we investigate the collapse and fragmentation of primordial, metal-free gas clouds. We explore the physics of primordial star formation by means of three-dimensional simulations of the dark…
Filamentary structures are ubiquitous from large-scale molecular clouds (few parsecs) to small-scale circumstellar envelopes around Class 0 sources (~1000 AU to ~0.1 pc). In particular, recent observations with the Herschel Space…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
We have modelled the circumstellar envelope of {\it o} Ceti (Mira) using new observational constraints. These are obtained from photospheric light scattered in near-IR vibrational-rotational lines of circumstellar CO molecules at 4.6…
The properties of the first galaxies are shaped in large part by the first generations of stars, which emit high energy radiation and unleash both large amounts of mechanical energy and the first heavy elements when they explode as…
The detection and subsequent characterisation of exoplanets are intimately linked to the characteristics of their host star. Therefore, it is necessary to study the star in detail in order to understand the formation history and…
The formation of planets is one of the major unsolved problems in modern astrophysics. Planets are believed to form out of the material in circumstellar disks known to exist around young stars, and which are a by-product of the star…
Extreme star formation includes star formation in starbursts and regions forming super star clusters. We survey the current problems in our understanding of the star formation process in starbursts and super star clusters - initial mass…
Studies of the CO and HI radio emission of some evolved stars are presented using data collected by the IRAM Plateau de Bure interferometer and Pico Veleta telescope, the Nan\c{c}ay Radio Telescope and the JVLA and ALMA arrays. Approximate…
We present results from the largest numerical simulation of star formation to resolve the fragmentation process down to the opacity limit. The simulation follows the collapse and fragmentation of a large-scale turbulent molecular cloud to…