The Virgo cluster spiral galaxy NGC 4654 is supposed to be a good candidate for ongoing ram pressure stripping based on its very asymmetric Hi distribution. However, this galaxy also shows an asymmetric stellar distribution. Numerical simulations using ram pressure as the only perturbation can produce a tail structure of the gas content, but cannot account for its kinematical structure. It is s...

A basic model of stellar structure is presented here. The sun is initially modeled using four fundamental equations of stellar structure. Since these equations are not analytically solvable, they were solved numerically using the Runge-Kutta fourth order approximation. Despite several firstorder approximations that were made, resulting values for density, mass, luminosity, and temperature were ...

We revisit the issues on the thermodynamic property of stellar self-gravitating system arising from Tsallis’ non-extensive entropy. Previous papers (Taruya & Sakagami, Physica A 307 (2002) 185 (cond-mat/0107494); ibid. (2002) in press (condmat/0204315)) have revealed that the extremum-state of Tsallis entropy characterized by the so-called stellar polytrope has consistent thermodynamic structur...

Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem tractable, we develop a semi-analytical stellar structure model that allows for physical understanding of these stars with unconventional parameters, as well as a mea...

We present a simulation of the spatial, luminosity and spectral distributions of four types of stellar objects. We simulate: (1) Galactic stars, based on a Galactic structure model, a stellar population synthesis model, stellar isochrones, and stellar spectral libraries; (2) white dwarfs, based on model atmospheres, the observed luminosity function , mass distribution, and Galactic distribution...

We revisit the issues on the thermodynamic property of stellar self-gravitating system arising from Tsallis’ non-extensive entropy. Previous papers (Physica A 307 (2002) 185; ibid. (2003) in press (cond-mat/0204315)) have revealed that the extremum-state of Tsallis entropy, so-called stellar polytrope, has consistent thermodynamic structure, which predicts the thermodynamic instability due to t...

Deep fields are unique probes of the Galactic halo. With a limiting magnitude of, e.g., I = 30 mag, all stars down to the hydrogen-burning limit are detected out to distances of 10 kpc, while stars with 0.5 solar masses could be traced out to distances of 400 kpc. Thus deep fields provide an opportunity to study both the structure of the Galactic halo and the mass function of population (Pop) I...

Our understanding of the physical and chemical structure of pre-stellar cores, the simplest star-forming sites, has significantly improved since the last IAU Symposium on Astrochemistry (South Korea, 1999). Research done over these years has revealed that major molecular species like CO and CS systematically deplete onto dust grains at the interior of pre-stellar cores, while species like N2H +...

The Sun is unique amongst stars in having a precisely determined age which does not depend on the modelling of stellar evolution. Furthermore, other global properties of the Sun are known to much higher accuracy than for any other star. Also, helioseismology has provided detailed determination of the solar internal structure and rotation. As a result, the Sun plays a central role in the develop...

Radio emission has been detected from all the stages of stellar evolution across the HR Diagram. Its presence reveals both astrophysical phenomena and stellar activity which, otherwise, would not be detectable by other means. The development of large, sensitive interferometers has allowed us to resolve the radio structure of several stellar systems, providing insights into the mass transfer pro...