ISSN:0004-6337    

DOI:10.1002/asna.19712930102

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe orientation parameterF=

ISSN:0004-6337    

DOI:10.1002/asna.19712930103

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractAt 1/λ = 2.79 μm−1, the comparison of a Be star with a nearby normal B star shows that the interstellar polarization of the Be star is diminished by a factor

ISSN:0004-6337    

DOI:10.1002/asna.19712930104

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of the radiation pressure of the interstellar radiation field on interstellar grains high above the galactic plane is estimated. It is shown that interstellar dust particles reaching large distances from the galactic plane are concentrated between 140 and 250 pc from the galactic plane. This result is in qualitative agreement with observations.

ISSN:0004-6337    

DOI:10.1002/asna.19712930105

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe time dependent polarization of the light of some red long period variables can be explained using the simple model of the oblique rotator. Near the magnetic poles the dust particles in the outer layers of the stellar atmosphere could be aligned in the magnetic field by the Davis‐Greenstein mechanism. For the stars V CVn, L2Pup, R Leo, and R Peg the spatial orientation of the rotational axis, the angle between the magnetic poles and the rotational axis and the period of the revolution of the magnetic poles around the rotational axis were derived from the observational material. The proposed hypothesis gives an explanation of the essential observational facts concerning the intrinsic polarization of some of the red variable

ISSN:0004-6337    

DOI:10.1002/asna.19712930106

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractSpectra of the Orion Nebula with a long slit (7' and 3' in the sky) and with exposures to the appearance of the visual continuum have been obtained for several positions in the field including, in particular, areas of low surface brightness. The variation of the ratioq= intensity of Balmer emission / intensity of continuous emission is studied. This ratio changes generally rather irregularly along the length of the slit and also from position to position. The spatial variation ofqis generally small with the exception of the center of the nebula, where it is particularly high.The variation of the ratioqcan be seen with a much higher surface resolution than in the spectra, when comparing monochromatic photographs taken in H α + [NII] with those taken in the continuum between the stronger emission lines.Within the larger part of the field of the nebula it is possible to distinguish between surface structures typical of the continuous emission and those typical of the hydrogen line emission. The persistence of this differentiation in many areas below the Balmer discontinuity as well as above Hα in the near infrared proves that for the subareas with the stronger continuum the continuous emission must be predominantly scattered light for the entire wavelength range from the ultraviolet to the near infrared. This criterion cannot be applied to areas where there exist no clear differences in the surface structure of the two types of emission. A determination of the Balmer and Paschen discontinuity may possibly lead to a decisio

ISSN:0004-6337    

DOI:10.1002/asna.19712930107

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractStoeckly and Dressler's suggestion (Ap. J.139.240, 1964) that the diffuse band at 4430 Å might be due to absorption by Ca atoms trapped in interstellar grains has been examined in a series of laboratory experiments. It has been assumed that Ca atoms are trapped in the dielectric mantles of interstellar grains. We have studied the spectrum of Ca trapped in solid benzene, diphenyl, triphenylene, toluene, decane, tetradecane, methanol and ethanol at temperatures below 120 °K. In most systems, several absorption bands attributable to the 4226 Å resonance line of Ca are seen in the 5500 – 3800 Å region. Benzene, the simplest member of the graphite precursor series, yields an uncomplicated spectrum which reduces to one broad band peaking at 4430 ± 20 Å at low Ca concentrations. This band has a total width at half peak intensity of ≅ 250

ISSN:0004-6337    

DOI:10.1002/asna.19712930108

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractA peak of the interstellar extinction curve near 1/λ = 4.5μm−1is tentatively interpreted as caused by a diffuse interstellar b

ISSN:0004-6337    

DOI:10.1002/asna.19712930109

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe presence of an apparent emission wing in the interstellar absorption band at λ = 4430 Å is confirmed. The observed profile of the band is in qualitative agreement with recent theoretical prediction

ISSN:0004-6337    

DOI:10.1002/asna.19712930110

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractExtinction curves have been calculated for Mie scattering by grains with a refractive indexm=n— ikwherenwas between 1.3 and 2.0 andkvaried from 0 to 0.5. A good fit for the observed interstellar extinction in the wavelength region of 0.1 to 2.0 μm was obtained for particles with radius 0.1 μm andm= 1.3 — 0.2 i. Inclusion of the changes in the refractive index in the vacuum ultraviolet region due to the strong absorptions of methane, ammonia and water does not appreciably alter these results. Theoretical extinction curves for the composite medium of H2O, NH3, CH4and graphite show a general agreement with the observed interstellar reddening curve over the whole spectral range, in addition to producing kinks in the far ultraviolet r

ISSN:0004-6337    

DOI:10.1002/asna.19712930111

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY