... Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity . As imbalances are reached, the star is driven to find a new Energy source. ... Pressure and gravitational forces are equal, the star is stable and its core is sufficiently hot to fuse Hydrogen into Helium More about main sequence stars . ... The luminosity generated by the core fusion of Helium into Carbon is far greater than the shell luminosity associated with the fusion of Hydrogen into Helium. ...

... The absolute flux calibration of NICMOS will be calculated from observations of standard stars with known flux distributions F( ). ... In order to expand the set of IR standard stars in the appropriate flux range for NICMOS, M. Rieke, R. Thompson, and collaborators at the University of Arizona are making photometric observations of solar-analog stars, which will be used to normalize the solar spectrum to the observed IR magnitudes. ... Relative flux references accurate to 1.5% for standard...

... 172 ] Briefly, the count rate at the detector from a source at a redshift z is . ... Figure 55 shows the ``Green functions'' for the double compact binary merging rate   evolution assuming no collapse anisotropy. ... Another way that diverse peculiarities in the - distribution induced by the sources evolution could arise is connected with a possible non-monotonic character of the star formation rate in galaxies. ... 22 ] Figure  56 shows two-dimensional cuts through the parameter space. ...

... Posts tagged ?standard candle? ... In addition to Bayesian methodologies, like this week?s astro-ph, studies on characterizing empirical spatial distributions of voids and galaxies frequently appear, which I believe can be enriched further with the ideas from stochastic geometry and spatial statistics. Click for what was appeared in arXiv this week. ... 1 Comment . ... If you find any problems of viewing the slog, please notify me. ... Entries RSS . ... Entries (RSS) and Comments (RSS) . ...

... In brief: the frequency-dependent radiative transfer equation is solved for a dust under assumption of spherically-symmetric geometry for its distribution taking into account particle size distribution and quantum heating effects for the very small dust particles. ... Table: Model parameters for IRAS04296+3429. ... parameter . ... hot dust shell) . ... The best fit to the spectral energy distribution of IRAS04296 is shown by heavy solid line (see Table2 for details concerning parameters of the model...

This service contributes to the International Service of Geomagnetic Indices (ISGI) of the IAGA . ... The Kp numbers of the previous month are available in tabular format . ... There are available also historical and current Kp and derived indices per anonoymos FTP (see below). ... U.S.A. FTP server: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/ . monthly update) . ... contains the monthly Kp / ap tables in a simple text format readable for both humans and computers (*.tab). ...

The project of the informational system creation on the problem of evolution of radio galaxies, as a part of the "Big Trio" project aimed on studing of distant radio galaxies, is designed. This system allows a user to operate with simulated curves of spectral energy distributions (SED) to estimate ages and redshifts by photometry data. Authors use SEDs of several models for different types of galaxies. ... The HTTP and e-mail access is organized to this system. ...

... The pinhole simulation program is a computationally and memory intensive task. ... A parallel version was developed instead, to enable distributed processing on a cluster of workstations. The program makes use of the Message Passing Interface (MPI) standard for parallel processing, implemented as an API (Application Programming Interface) to the Local Area Multicomputer (LAM) programming environment developed at the Ohio Supercomputer Center. ...

... The material in "From Stargazers to Starships" meets several important requirements of the national standards. Pages cited below are from National Science Education Standards National Academy Press, Washington 1995. ... For example: the sections on astronomy not only describe calendars and sundials (including their construction), but also the astronomy of the ancient Greeks, including two different ways in which ancient Greeks estimated the distance to the Moon. ...

... Oke (AJ, 99, 1621, 1990) has provided absolute spectral energy distributions covering the wavelength range 3200 to 9200A in AB magnitudes for 25 stars. ... The reduced magnitudes are tabulated at 1A intervals from 3300 to 4700A and at 2A intervals from 4700 to 9200A. Comparison of the fluxes with those determined elsewhere showed that Oke's absolute magnitudes are systematically brighter by 0.04 mag. The magnitudes and fluxes plotted have been corrected for this effect. ...

... Fortranљ66 . ... Fixed form . ... Whole Fortranљ66 . ... Continuation line indicated in column