... 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 first task assumes the searching for chemical composition and sizes of particles which give the wavelength dependence of the extinction efficiencies close to the observed dependence of . Figure 7: Wavelength dependence of the extinction efficiency factors for homogeneous spherical particles of different sizes consisting of astronomical silicate and amorphous carbon. The dashed segment shows the approximate wavelength dependence of the mean galactic extinction curve at optical wavelengths. ...

... gradients dependencies on solar wind parameters and IMF; . ... fate of thermal plasma at the dayside magnetopause. velocity-dispersed injections of the thermal and superthermal ions from LLBL at cusp and cleft (lowest energy VDIS-2 events); . ... outer cusp processes, role of outer cusp indentation, plasma entry (laminar reconnection, turbulent diffusion, others), role of turbulent boundary layer; . how is the magnetosheath plasma heated near magnetopause and cusp? . ... cusp/cleft wave emissions. ...

Orbital intersection . ... Structure of Taurid stream . ... Meteoroid swarm and Taurid fireballs . ... The following four diagrams schematically show four different Taurid orbits and the orbits of Earth and Jupiter. ... The Taurid stream contains particles (small, solid grains) at different stages of their precession cycles. ... The study of when a meteor stream can produce a meteor shower is the study of when precession brings orbits to intersection with Earth, or e.g. with Mars . ...

... Just as magnetic storms are composed of substorms, the substorms themselves seem to be composed of smaller scale events. ... steplike expansion of the auroral bulge (Vorobjev and Rezenov, 1973; Sergeev and Yahnin, 1979; Murphree and Cogger, 1992; Nakamura et al., 1993) . ... 1990) . ... fine structure in the bursts of bremsstrahlung X-rays (Lazutin et al., ... Nakamura, R., T. Oguti, T. Yamamoto, and S. Kokubun, Equatorward and poleward expansion of the auroras during auroral substorms, J. Geophys. ...

... For SIMS (Secondary Ion Mass Spectrometry) analysis, a solid surface is bombarded by primary ions of some keV energy. ... The subsequent mass analysis of the emitted ions provides detailed information on the elemental and molecular composition of the surface. ... Extremely short ion pulses with a duration below . ... By rastering a fine-focussed ion beam over the surface, like an electron beam in an electron microprobe, mass resolved secondary ion images (chemical maps) can be obtained...

The quantity of dust in a spiral disk can be estimated using the dust's typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. ... Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ...

. Figure 3. SOHO/EIT derotated 6-hour difference images of the 14 July 2000 event in four diverse-temperature lines 171, 195, 284, and 304 . For each line, the 13 UT heliogram is subjected to the suppression of the `snowstorm' produced by energetic particles, and only dimmings (i.e. structures of negative resulting intensity) are shown. Different appearance of the images is due to different exposure times.

... Programme . ... Abstract: Chandra data taken as part of the Very Large Program (VLP) show that the X-ray spectrum in Centaurus A's jet steepens with increasing distance from the jet axis. ... Electrons with sufficient energy to emit synchrotron X-rays must be accelerated locally to the knots, since their energy loss timescale is short compared with any dynamical timescale associated with fluid motion. ...

... The HH flow associated with young stellar object HL Tau has an exciting history and even until now the origin of some its features is not clear yet. ... Knotty structures of Herbig-Haro jets are common phenomena and knowing the origin of such structures is essential for understanding the processes of jet formation. ... In the flow detected compact knots with high (-150 km/s) and bow shape structures in front of those, with low radial velocities (-50 km/s). ...

Dwarf novae are a subclass of cataclysmic variable stars in which a late-type secondary fills its Roche lobe and transfers mass to a white dwarf primary via an accretion disc. ... Those spiral structures are very similar to the spiral shocks discovered by Sawada, Matsuda & Hachisu (1986) in 2D finite difference numerical simulations in accretion discs. In this poster, we want to compare 2D numerical simulations of accretion disc with the observations of SH2 . ...

Scale-heights of the Galactic disk subsytems with different ages and metallicities . V.Marsakov & Yu. ... It is based on the fact, that all stars cross the disk plane several times during their Galactic orbital period. ... We have used our representative sample of nearby disk F2-G2 stars Marsakov & Shevelev (1995) in which fundamental stellar parameters was determined on the basis of published date on uvby-photometry, proper motion and radial velocities. ... Marsakov V.A., Shevelev Yu.G. Bull. ...

The subdirectory steppe contains the time series recorded at Zymlyanskaya steppe in Rostov-na-Donu region. The data recorded in Moscow are placed at subdirectory moscow . ... The first one is the horizontal wind velocity, the second one is vertical velocity. ... The first two digits of filename is an identification of recording, and the third digit (1-6) is the number of time series. The first number N in any file is the total number of the points, followed by the N data values. ...

This home page belongs to small group of scientists working at . Sternberg Astronomical Institute which is a part of Moscow State University . ... Электронная библиотека научно-технической и художественной литературы (доступна только из ГАИШ) . ... Local staff . Dr. Edward Kononovich (konon -at- sai.msu.ru), Associate Professor . ... Dr. Sergey Ayukov (asv -at- sai.msu.ru), Research Fellow, Webmaster of the group . ... Joint seminar of Solar Studies Structure Group and Solar Photometry Group . ...

... Because of the low conductivity, the magnetic coupling is weak and depends critically on density, temperature, ionisation rate and charged species. ... Implications When the Hall regime dominates near the midplane and ambipolar diffusion is dominant closer to the surface, a thicker layer of the disc is unstable to MRI perturbations and modes grow faster than under the ambipolar diffusion approximation. ... Right panel: For weak coupling, Hall limit perturbations grow until vA/cs ~ 2.9. ...

Geometric Algebra 3 Dirac Theory and Multiparticle Systems Chris Doran Astrophysics Group Cavendish Laboratory Cambridge, UK Dirac Algebra · Dirac matrix operators are · These act on 4-component Dirac spinors · These spinors satisfy a first-order wave equation MIT3 2003 2 STA Form · Adapt the map for Pauli spinors · Action of the various operators now Imaginary structure still a bivector Dirac equation MIT3 ...

... Table data are arranged in columns and rows, and stored in MIDAS files with the extension .tbl . ... An item in a table is accessed by giving its column and row in addition to the table name. The row number can either be given as an absolute value (i.e. the sequence number) or indicated by the value in a previously defined reference column. ... A table can be always expanded in the sense that its number of columns and rows is automatically increased when the allocated space is exceeded. ...

Microsymposium 38, MS082, 2003 (A4 format) EVALUATING THE STRUCTURE OF THE SURFACE LAYER OF MERCURY. ... Photometric Analysis of the Lunar Surface Analogue. ... The phase function obtained directly on some segments of the lunar surface: 1- phase function of the Moon, 2 - phase function of Mercury, 3 - phase function of segments, converted to the lunar phase function system (correlation 0.8), 4 - phase function of segments, converted to the Mercurian phase function (correlation 0.9). ...

... Magnetic fields, subatomic particles, etc., traveling in different directions fill the universe. Do they deflect or otherwise affect one another? If so, isnт??t the information we get from them distorted? ... Neutrino astronomy, which is still in its infancy, is attractive because neutrinos interact so weakly with matter that few of these distorting effects occur. Get instant access to subscriber content on Astronomy.com! ...

I'm interested in the structure of interstellar ``clouds'' (filaments, sheets, or whatever) of gas and dust over a wide range of scales, from Galactic spiral arms to AU-scale features -- also how these structures form and interact. ... The possibility of clumpy dust scattering in the Pleiades reflection nebula, which might explain its otherwise surprising UV scattering properties . ... Intricate structure of H I emission and self-absorption in the CGPS . ... Fractal studies of molecular clouds . ...