The silicates that produce the 10 and 18 micron features appear to be broadly similar to terrestrial minerals such as Forsterite and Enstatite. ... Where pre-solar silicate dust grains can be isolated from meteorite material, these also tend to be Mg-rich silicates rather than Fe-rich silicates. ... It has been suggested that the interstellar silicate grains have a different 10 micron feature profile than what is observed for the silicates around evolved stars. ...

... The larger image shows the entire nebula; the inset picture captures the complicated structure surrounding the dying star. The remarkable features of this nebula are the numerous holes in the inner shells with jets of material streaming from them. ... The multiple shells of material ejected by the dying star give this planetary nebula its odd form. ... At least four jets of material can be seen in the "full nebula" image: a pair near 6 and 12 o'clock and another near 2 and 8 o'clock. ...

... 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). ...

... Tonight's Sky . ... Sky this Month . ... Star Atlas . ... stars . ... The Sky This Week: April 1 - 10 . ... Observing springtime deep-sky objects with a large telescope . ... Why do some stars appear to flash a variety of different colors when you look at them through a telescope? ... So, Earthт??s atmosphere will bend some colors from especially bright stars more so than others, which makes the source look like itт??s flashing colors. Get instant access to subscriber content on Astronomy.com! ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. January 20, 1998 . Arachnoids on Venus . Credit: Magellan Team , JPL , NASA . Explanation: Arachnoids are large structures of unknown origin that have been found only on the surface of Venus . ... Radar echoes from the Magellan spacecraft that orbited Venus from 1990 to 1994 built up this image. ... About APOD > . ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... The Cat's Eye Nebula . ... The USNO Millennium Time Ball . ... Spanning over 25,000 light-years, comparable to the distance from the Sun to the center of our own Milky Way galaxy, a cosmic jet seen in X-rays blasts from the center of Centaurus A. Only 10 million light-years away, Centaurus A is a giant elliptical galaxy - the closest active galaxy to Earth. In the Heart of the Tarantula Nebula . ... Neptune is the eighth most distant planet from the Sun, thirty times the Earth-Sun distance. ...

... W e study the SPS for each of regions in the Bridge, as a function of velocity and of velocity integrated width. ( v): There is considerable variation in the HI structure throughout the MB. W e probe the power spectra for four different regions in the Bridge (see Figure 1). ... W e find that the northern regions have a peak value of (v) which is ver y distinct from the sout her n regio ns. ( dv): The variation of the power spectrum index, as a function of velocity is shown in Figure 3. ...

... Here some data observed on the 6m telescope with IFP installed in the OLD focal reducer are presented. ... Mkn 3: velocity field . ... NGC 5252: [OIII] image . ... NGC 5252 was observed 23 Feb. 1998 in the [OIII]5007 emission line with CCD TK1024 as detector. ... We observed the ionized gas velocity fields of the spiral galaxies with two purpose. ... Restored velocity field of NGC 157 in the reference frame rotating with the pattern speed overlaid on the Ha image of the galaxy . ... NGC 4100 . ...

... X CB (X) Opening of a set X by a disk B. Closing of a set X by a disk B. Science-Driven Feature Selection (a) (b) Mount Wilson Classification The Mount Wilson classification scheme groups sunspots into four classes based on the complexity of magnetic flux distribution in associated active regions [1]: class : groups dominated by a single unipolar sunspot class : a pair of sunspots of opposite magnetic ... Convex hulls are utilized to measure polarity mixture in (j). ...

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 . ...

... 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. ...

Subject, Problems and Objects of Theoretical Astrophysics. ... Stellar Photospheres, Their Features. ... Physics of Continuous Radiation Absorption in Stellar Photospheres. ... Continuous Radiation Absorption in Stellar Photospheres of Various Spectral Classes. Solar Type Photospheres. ... Characterisics of Absorption Lines. ... Interstellar Absorption Lines, Their Features. ... Physical and Dynamic Features of Interstellar Medium, Which Follows from Observations of Interstellar Absorption Lines. ...

Astronotes Armagh Planetarium's Stellar Blog! ... This image combines orbital imagery with 3-D modelling to show flows that appear in spring and summer on a slope inside Mars' Newton crater. ... Warm season flows on a slope in Newton Crater, possible evidence of salty liquid water active on Mars today. Image credit: NASA) . ... Frozen water is common on and under the surface of Mars but these images are the best evidence to date for the presence of liquid water on the Martian surface today. ...

Giant radio galaxies constitute a class of radio sources with linear sizes on the megaparsec scale (Saripalli 1988). ... The Westerbork Northern Sky Survey (WENSS) has discovered several cases of "inner-double" or "double-double" giant radio galaxies: the findings suggest that such structures predominantly occur among the larger of radio galaxies. ... Close to the core of B0114-476, a narrow jet-like feature is seen directed toward the southern inner lobe which also has the brighter hotspots. ...

... A new IRAF task has been developed that automatically identifies linear (line-like) features in an image or set of images. ... In order to automatically detect linear features, the first step is to select pixels in the image (Fig. 1 , left panel) that fall within a given data value range. ... Another aspect of extended linear features is that the image space pixels that describe them are in some way adjacent to one another and have a minimum and maximum length. ...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

Solar Large-Scale Chains: Some Events . ... The chains appear to light up separators or quasi-separatrix layers between different interacting large-scale magnetic flux systems in the global solar magnetosphere and, in particular, to outline large-scale coronal structures involved in the CME process. ... Some features of the chains and their relations to CMEs are illustrated for a number of halo CME-associated events. 23 events of 1997-2000 . ... Halo-CME-associated events of November 1997 . ...

The spectrophotometrical complex of the 6-m telescope in Nasmyth-1 focus . ... A new sample of 360 blue compact galaxies with a strong star formation was build on the base of the Second Byurakan Survey. ... More that 20 galaxies with the extremely low-abundances of heavy elements in the range of 1/30-1/10 of the Sun's one, were found. ... During the 15-years observation term near 500 spectra of the unique source SS~433, from which the relativistic jets were found for the first time, were obtained. ...

... Grants, Programs, Contracts . ... Grant of the Russian Federal Property Fund: . 12-02-00537 'Specific features of formation of nanostructure at plastic deformation of amorphous alloys' (A.S. Aronin) . ... 09-02-00529-'Role of shear bands in formation nanocrystal structures at deformation of amorphous alloys' (A.S. Aronin) . ... Nanocrystal structure in alloys on the base of transitional metals: formation, atomic and magnetic structure, magnetic properties (A.S.Aronin) . ... LSR ISSP RAS . ...