Related papers: Circumstellar rings, flat and flaring discs
Recent observational studies of intermediate- and high-mass star-forming regions at submillimeter and infrared wavelengths are reviewed, and chemical diagnostics of the different physical components associated with young stellar objects are…
Effective star formation rates in tabular form are computed which yield a prescription for the star formation activity in model galaxies as a function of ambient density, metallicity, and stellar feedback. The effects of supernova…
The relations between star formation and properties of molecular clouds are studied based on a sample of star forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of…
We consider the curvature emission properties from relativistic particles streaming along magnetic field lines and co-rotating with pulsar magnetosphere. The co-rotation affects the trajectories of the particles and hence the emission…
Circumstellar disks are considered to be the birthplace of planets. Specific structures like spiral arms, gaps, and cavities are characteristic indicators of planet-disk interaction. Investigating these structures can provide insights into…
Recent X-ray observations of microquasars and Seyfert galaxies reveal the broad emission lines in their spectra, which can arise in the innermost parts of accretion disks. A theoretical analysis of observations and their interpretations…
An extensive modelling of CO line emission from the circumstellar envelopes around a number of carbon stars is performed. By combining radio observations and infrared observations obtained by ISO the circumstellar envelope characteristics…
Two parameters are developed to analyze the CCD images from ground-based and/or space telescopes. The first parameter, deduced from the intensity profile of the object sharp, is useful to resolve stars and hot pixels. The second parameter…
Nearly all young stars are initially surrounded by `protoplanetary' discs of gas and dust, and in the case of single stars at least 30\% of these discs go on to form planets. The process of protoplanetary disc formation can result in…
Holes and clumps in the interstellar gas of dwarf irregular galaxies are gravitational scattering centers that heat field stars and change their radial and vertical distributions. Because the gas structures are extended and each stellar…
The properties and star formation processes in the far-outer disks of nearby spiral and dwarf irregular galaxies are reviewed. The origin and structure of the generally exponential profiles in stellar disks is considered to result from…
Through the study of two absorption spectral features in the optical range (Mg2 and the 4000 A break), we find evidence for star formation in the inner regions of cooling-flow galaxies. The application of simple stellar population models…
We have been represented the collective information of estimation procedures of parameters of the open clusters and put them together for showing the importance of clusters to understand their role in stellar evolution phenomenon. Moreover,…
We compute radial color gradients produced by an outwardly propagating circular wave of star formation and compare our results with color gradients observed in the classical ring galaxy, the ``Cartwheel''. We invoke two independent models…
We investigate the properties of circumplanetary discs formed in three-dimensional, self-gravitating radiation hydrodynamical models of gas accretion by protoplanets. We determine disc sizes, scaleheights, and density and temperature…
Massive star formation in the central regions of spiral galaxies plays an important role in the dynamical and secular evolution of their hosts. Here, we summarise a number of recent investigations of the star formation history and the…
The process of forming a circumbinary planet is thought to be intimately related to the structure of the nascent circumbinary disc. It has been shown that the structure of a circumbinary disc depends strongly on 3-dimensional effects and on…
In this talk, I report results from galaxy merger simulations, which suggest the existence of a ring of star formation produced by close galaxy encounters. This is a generic feature of all galaxy interactions, provided that the disc spins…
We discuss the interpretation of distortions to stellar spectral lines with particular attention to line bisectors in the presence of an orbiting planetary companion. We present a simple model whereby light reflected by the companion can…
A detailed analysis is given of the angular distribution of an charged particle moving along the arc of a circle. The areas of different angular distribution behavior are highlighted and studied.