Interstellar Extinction, Polarization, and Grain Alignment in the Sh 2-185 (IC 59 and IC 63) Region

We have analysed the standards of the MK system in the B0-F5 spectral region with the help of Hipparcos parallaxes, using only stars for which the error on the absolute magnitude is ≤ 0.3 mag. The sample stars (about one hundred) were scrutinized for companions and for interstellar extinction. We find that the main sequence is a wide band and that, although in general giants and dwarfs have different absolute magnitudes, the separation between luminosity class V and III is not clear. We conclude that there is no strict relation between luminosity class and absolute magnitude. The relation is only a statistical one and has a large intrinsic dispersion. We have analysed similarly the system of standards defined by Garrison and Gray (1994) separating low and high rotational velocity standards. We find similar effects as in the original MK system.

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Analysis of Interstellar Extinction towards the Hypergiant Cyg OB2 No. 12

Open Astronomy ◽

10.1515/astro-2017-0108 ◽

2016 ◽

Vol 25 (1) ◽

Author(s):

O. V. Maryeva ◽

E. L. Chentsov ◽

V. P. Goranskij ◽

S. V. Karpov

Keyword(s):

Interstellar Extinction ◽

Stellar Association ◽

The Galaxy ◽

The Mean

AbstractThe Cyg OB2 stellar association hosts an entire zoo of unique objects, and among them – an enigmatic star Cyg OB2 No. 12 (Schulte 12, MT 304). MT 304 is enigmatic not only due to its highest luminosity (according to various estimates, it is one of the brightest stars in the Galaxy), but also because its reddening is anomalously large, greater than the mean reddening in the association. To explain the nature of anomalous reddening (

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Fabrication and characterization of highly textured (Bi,Pb)2Sr2Ca2Cu3Ox superconducting ceramics using high magnetic field and cold isostatic pressing

Journal of Materials Research ◽

10.1557/jmr.1995.2433 ◽

1995 ◽

Vol 10 (10) ◽

pp. 2433-2443 ◽

Cited By ~ 4

Author(s):

Wai Lo ◽

R. Stevens ◽

R. Doyle ◽

A.M. Campbell ◽

W.Y. Liang

Keyword(s):

Magnetic Field ◽

Electron Microscopy ◽

Cold Isostatic Pressing ◽

Sintered Ceramic ◽

Grain Alignment ◽

Isostatic Pressing ◽

Transmission Electron ◽

Superconducting Ceramics ◽

High Degree

High textured (Bi,Pb)2Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi,Pb)2Sr2Ca2Cu3Ox suspended in an organic medium by means of a high de magnetic field (6 T) at room temperature followed by cold isostatic pressing. The proportion of the (Bi,Pb)2Sr2Ca2Cu3Ox phase in the precursor powder was carefully controlled, and the characteristics of the powder, such as size distribution and morphology, were determined. A high degree of grain alignment was found in the specimens after the magnetic alignment, although the bulk density of the materials was low. Cold isostatic pressing substantially increased the density of the magnetically prealigned specimens which also resulted in a slight decrease in the degree of grain alignment. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction due to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered ceramic have been studied using texture goniometry, high resolution scanning electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.

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Effect of grain alignment on magnetic properties of Hg(Re)-1223 superconductors

Physica C Superconductivity ◽

10.1016/s0921-4534(02)00999-1 ◽

2002 ◽

Vol 372-376 ◽

pp. 1876-1879 ◽

Cited By ~ 4

Author(s):

N Sakamoto ◽

S Noguchi ◽

T Akune ◽

Y Matsumoto

Keyword(s):

Magnetic Properties ◽

Grain Alignment

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A polycrystalline graphite model for the 2175 Å interstellar extinction band

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2009.14484.x ◽

2009 ◽

Vol 394 (4) ◽

pp. 2175-2181 ◽

Cited By ~ 15

Author(s):

Robert J. Papoular ◽

Renaud Papoular

Keyword(s):

Interstellar Extinction ◽

Polycrystalline Graphite

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Variation in Degree of Hornblende Grain Alignment within two Boudinage Structures

Canadian Journal of Earth Sciences ◽

10.1139/e71-010 ◽

1971 ◽

Vol 8 (1) ◽

pp. 144-149 ◽

Cited By ~ 6

Author(s):

W. M. Schwerdtner ◽

P. M. Sheehan ◽

J. C. Rucklidge

Keyword(s):

Inverse Relationship ◽

Finite Strain ◽

Great Circle ◽

Preferred Orientation ◽

Grain Alignment ◽

X Ray ◽

Fabric Diagrams ◽

Principal Directions

The degree of preferred orientation of hornblende in two boudinage structures is analyzed by means of an X-ray texture goniometer. Relative values of reflected intensity for {110} are plotted on the stereographic net, and contoured at convenient intervals. As in conventional fabric diagrams for hornblende, {110} define a great-circle girdle whose breadth reveals the density of unimodal grouping of [001].The density of grouping of [001] varies throughout both boudinage structures. It decreases with increasing extension in structure A, and seems to have a similar trend in structure B, where the determined variation in degree of grain alignment is of doubtful statistical significance.The inverse relationship between the degree of preferred orientation and the magnitude of extension may be attributed to rotation of the principal directions of finite strain during syntectonic crystallization. Alternatively, reorientation of strained grains by annealing recrystallization may have produced the inverse trend.

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