Results 191 to 200 of about 1,478 (224)
Some of the next articles are maybe not open access.
Circumstellar matter in Herbig AeBe stars
Infrared Physics & Technology, 1994Abstract I briefly summarize the observational evidence for large envelopes in the immediate environment of Herbig AeBe stars, and the results of star + envelope models. Then, I discuss two alternative possibilities to account for the observed mid-infrared fluxes, namely as the emission of very small grains (VSG) and policyclic aromatic hydrocarbons (
openaire +1 more source
Interaction of Supernova Eject with Interstellar and Circumstellar Matter
Annals of the New York Academy of Sciences, 1984The series of one-dimensional numerical simulations of supernova ejecta interactions with both interstellar and circumstellar matter whose results are presented was prompted by Chevalier's (1982) indication that the late time behavior of such interactions can be modeled by certain exact analytic self-similar solutions corresponding to ideal gas spheres
E. P. LIANG, R. A. CHEVALIER
openaire +1 more source
Stellar Death: Ejecta and Circumstellar Matter
1997IR 15 milli-arcsecond interferometry in the 5 – 15 µm wavelength region of the circumstellar environments of AGB stars probes the dust condensation zones close to the stellar photospheres. Interferometric measurements which spatially resolve Galactic novae will provide distance determinations, can reveal dense knots in the structure of the ejected ...
openaire +1 more source
The Shape of the Extinction Curve of Opaque Circumstellar Matter
1996The extinction curves observed in the spectra of Be stars, characterized by stellar emission of both hydrogen and helium lines, show several peculiarities. The extinction bump near 2200 A is apparently absent in the extinction law of the circumstellar dust grains.
Walter Wegner, Jacek Krełowski
openaire +1 more source
Circumstellar matter of SN1987A and soft X-ray emission
Nature, 1988X-ray emission from supernova 1987A has been observed continually by the Ginga satellite since July 1987. The observed X-ray spectrum1,2 has two components: hard X-rays, above 15 keV in energy, have a nearly flat spectrum, and are thought to be Compton-degraded γ-rays from the decay of 56Co (ref. 3); the soft component (
K. Masai +4 more
openaire +1 more source
Nova experiments to simulate the interactions of SN1987A with circumstellar matter
The 13th international conference on laser interactions and related plasma phenomena, 1997Nova laser target blowoff impacting low density foams can be used to simulate the expanding ejecta of SN1987A interacting with the circumstellar matter, especially the pending impact with the circumstellar ring discovered by optical astronomers. While the actual astrophysical phenomena cannot be studied in their totality in the laboratory, it seems ...
E. Liang +5 more
openaire +1 more source
Spot Activity and Circumstellar Matter in II Peg
1988Infrared and V band photometry of the RS CVn system II Peg, carried out in 1984 and 1986, has been analysed with a simple model in order to follow the evolution of the activity of spots over the surface of the visible star. The group of spots has been concentrated in longitude from 1984 to 1986 covering about 27% in 1984 and 44% of the visible disk in ...
C. Lazaro, M. J. Arévalo
openaire +1 more source
Circumstellar Matter and Winds in Young Stars
1988The morphology of the circumstellar regions around low-mass protostars and pre-main-sequence stars is analysed in light of a wide range of observations (optical, near-, mid- and far-infrared, radio continuum, radio molecular emission). Optical and radio jets, near-infrared H2 and far-infrared [OI] fine structure lines are used to characterize the mass ...
openaire +1 more source
Mass-Losing Pulsating Stars and their Circumstellar Matter
2003I Recent Results of Massive Photometry.- The Sequence of Mass-Losing AGB Stars in the Magellanic Clouds.- Three Aspects of Red Giant Studies in the Magellanic Clouds.- Luminosities of AGB Variables.- Photometric Properties of Long-Period Variables in the Large Magellanic Cloud.- Stellar Sources in the ISOGAL Intermediate Bulge Fields.- GAIA: AGB Stars ...
openaire +1 more source
Current loop models for the circumstellar matter in SN 1987A
IEEE Transactions on Plasma Science, 1992Some properties of current-loop models are explored, and some implications are discussed. The elliptical ring observed to be centered on the supernova can be interpreted as light from ions trapped in the magnetic field of a circular current loop. The current is 1.5*10/sup 12/ A for a model where gravitational force on 0.03 solar masses of trapped ...
openaire +1 more source