Results 81 to 90 of about 293,009 (201)

Nanosilicates and molecular silicate dust species: properties and observational prospects

Frontiers in Astronomy and Space Sciences
Silicate dust is found in a wide range of astrophysical environments. Nucleation and growth of silicate dust grains in circumstellar environments likely involves species with diameters ranging from <1 nm (molecular silicates) to a few nanometers ...
Stefan T. Bromley, Stefan T. Bromley
doaj   +1 more source

The circumstellar environment of EX Lupi: SPHERE and SINFONI views [PDF]

, 2020
Context. EX Lup is a well-studied T Tauri star that represents the prototype of young eruptive stars known as EXors. They are characterized by repetitive outbursts that are due to enhanced accretion from the circumstellar disk onto the star.
Dominik, C., Zurlo, A., Kóspál, Á., Maurel, D., P. Ábrahám, Menard, F., F. Menard, Gratton, R., Blanchard, P., S. Desidera, C. Ginski, Ábrahám, P., Holstein, R.G. van, P. Blanchard, Weber, L., Weber, L,., van Holstein, R.G., Baruffolo, A., Mesa, D., V. D’Orazi, R. G. van Holstein, A. Garufi, Á. Kóspál, van Holstein, R. G., Rigliaco, E., Henning, T., D'Orazi, V., E. Rigliaco, Desidera, S., A. Baruffolo, L. Weber, D. Mesa, D. Maurel, Ginski, C., Garufi, A., A. Zurlo, R. Gratton, C. Dominik, T. Henning, Dominik, C.; id_orcid, Kóspál, Ágnes, Ábrahám, Péter, D’Orazi, V.   +42 more
core   +1 more source

Formation of SiC grains and the 11.3μm feature in circumstellar envelopes of carbon stars. [PDF]

, 1996
We propose that the so-called 11.3μm emission features observed toward carbon stars can be attributed to small spherical core-mantle type grains consisting of a SiC core and a carbon mantle or small carbon grains containing SiC as an impurity.
Henning, Thomas, Stognienko, Ralf, Kozasa, Takashi, Dorschner, Johann   +3 more
core  

Circumstellar Grains and the Intrinsic Polarization of Starlight [PDF]

, 1974
Twenty-four late-type variable stars exhibiting intrinsic variable polarization have been monitored over the range 3.5 μ to 11 μ for several cycles. No conclusive evidence for gross changes in the amount of c1rcumstellar grains have been found.
Forrest, William John
core  

A Theoretical Study of Carbon Nanotube Formation: Carriers of the Diffuse Interstellar Bands?

The Astrophysical Journal
Density functional theory (DFT) calculations have been conducted to probe the formation of carbon nanotubes (CNTs) from graphitic sheets in the presence of a simulated circumstellar shock wave.
A. Thakur, P. J. Lohr, J. J. Bernal, A. Asaduzzaman, K. Muralidharan, T. J. Zega, L. M. Ziurys   +6 more
doaj   +1 more source

VLTI/MATISSE observations of the hot dust around β Pictoris Observing faint objects with MATISSE★

Astronomy & Astrophysics
Context. Hot exozodiacal dust has been detected in approximately 20% of nearby main-sequence stars, indicating that it is a common feature in extrasolar planetary systems. However, their spatial distribution and grain properties remain poorly understood.
Priolet P., Augereau J.-C., Milli J., Matter A., Lopez B., Beust H., Varga J., Boley P., Danchi W.-C., Foteini L., Henning T., Houllé M., Letessier M., Millour F., Scigliuto J., Weigelt G., Wolf S., Absil O., Berger J.-P., Bouarour Y.-I., Bourdarot G., Defrère D., Desgrange C., Le Bouquin J.-B., Iglesias D., Stuber T. A., Berio P., Bettonvil F., Cruzalèbes P., Heininger M., Isbell J. W., Lagarde S., Meilland A., Petrov R., Robbe-Dubois S.   +34 more
doaj   +1 more source

Configurational anisotropy in single-domain and pseudosingle-domain grains of magnetite [PDF]

, 2006
In classical domain theory, single-domain (SD) grains change their magnetization by coherent rotation, where the energy barrier to domain reversal is provided by the magnetocrystalline anisotropy or by shape anisotropy for elongated grains.
Williams, W., Paterson, G.A., Muxworthy, A., Paterson, Greig A., Williams, Wyn; id_orcid, Muxworthy, Adrian R., Muxworthy, Adrian R, Paterson, Greig A, Williams, Wyn   +8 more
core   +1 more source

Hot components and circumstellar grains in M supergiant syncretic binaries

The Astrophysical Journal, 1988
Ultraviolet and infrared spectra were obtained in order to study grains in cool star and hot star syncretic type binaries. Grains are found in only about half of the syncretic systems. The results suggest that grains have not formed in many syncretic systems because of ultraviolet radiation from the hot star.
Richard H., Jr. Buss, Theodore P., Jr. Snow   +1 more
openaire   +1 more source

On the size distribution of newly formed grains in red supergiant atmospheres [PDF]

, 1989
Theoretical ultraviolet extinction curves have been calculated for comparison with observed curves for circumstellar dust in M supergiants. The theoretical curves assumed a silicate grain composition, because silicate grains are expected in the oxygen ...
Snow, Theodore P, Seab, C Gregory
core  

DISTRIBUTIONS OF HOT MOLECULES IN YOUNG CIRCUMSTELLAR DISKS

, 2010
We have studied the effect of the gas accretion flow on the distribution of molecules in hot inner regions of young circumstellar disks. The gas-phase reactions initiated by evaporation of icy mantle on dust grains are calculated along the accretion ...
Y. Nakagawa, H. Nomura, T. J. Millar, Nomura, H., Aikawa, Y., Nakagawa, Y., Millar, TJ, Y. Aikawa   +7 more
core   +1 more source