Indications of twist in the epsilon ring of Uranus

1984 ◽  
Vol 75 ◽  
pp. 193-195
Author(s):  
R. Vasundhara ◽  
J.C. Bhattacharyya
Keyword(s):  
Fine Structure ◽  
Optical Depth ◽  
Light Curves ◽  
Systematic Variation ◽  
Condensed Material ◽  
Ring Assembly ◽  
Ring Segment ◽  
Fine Structures ◽  
Twisted Bundle ◽  
F Ring

A comparison of light curves during occultation of stars by ε ring of Uranus indicate that this ring assembly possesses stable fine structures. The light curves observed during several events show almost similar fine structure across its width. Nicholson et al. (1982) quantitatively compared the separation of the five optical depth maxima, and concluded that no systematic variation of the normalised spacing, either with ring segment width or with data of observation was apparent. We have investigated the possibility of this having structure of a twisted bundle of narrow lanes of condensed material similar to that of Saturn’s F ring (Ref 4) and report the findings.

scholarly journals Fine Structure and Dynamics of the Inner Corona

1977 ◽  
Vol 43 ◽  
pp. 9-9
Author(s):  
G.E. Brueckner ◽  
J.D.F. Bartoe ◽  
M.E. VanHoosier
Keyword(s):  
Solar Wind ◽  
Fine Structure ◽  
Thermal Energy ◽  
Column Density ◽  
Line Profiles ◽  
Quiet Sun ◽  
Structure And Dynamics ◽  
Fine Structures ◽  
The Doppler Effect ◽  
Average Size

High spectral (0,05 Å) and spatial (⋍ 1000 km) resolution spectra of the Fe XII line 1349.4 Å reveal the existence of coronal fine structures in the quiet sun against the solar disk. These coronal bright elements have an average size of 2000-3000 km; their column density can be 3 x 1017 cm –2 . In the quiet sun, outward streaming velocities of 10-15 km sec –1 can be measured by means of the Doppler effect. The total kinetic and thermal energy of the outstreaming gas can be estimated to be larger than 1 x 10 5 ergs cm –2 sec –1, enough to account for the heating of the corona and the losses of the solar wind. At the outer limb (cos θ ⋍0.1) line profiles show a strong blue asymmetry, which could be caused by expanding material in a piston-driven shock, whereby the opaque, cool piston causes the asymmetry of the line profile.

scholarly journals The nuclear spin of iodine I— fine structure in the first spark spectrum

1935 ◽  
Vol 149 (867) ◽  
pp. 269-281 ◽  
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Nuclear Spin ◽  
High Frequency ◽  
Complete Resolution ◽  
Electrodeless Discharge ◽  
A Value ◽  
Fabry Perot ◽  
Fine Structures ◽  
The Individual

In an earlier paper on the fine structures of the visible lines in the arc spectra of bromine and iodine an attempt was made to estimate the nuclear spin of iodine, and a tentative value of 9/2 was proposed. The iodine arc lines were excited by a high frequency electrodeless discharge in pure iodine vapour and examined with a silvered Fabry-perot interferometer. The fine structures in the arc lines are small, and as the patterns are highly complex and the individual components not very sharp, interpretation was difficult. It was concluded with certainty that the nuclear spin was at least equal to 5/2, but one line in particular suggested a value of 9/2. This was indefinite, and in view of the uncertainty a thorough examination of both the arc and spark spectra of iodine has been undertaken. A preliminary notice has already appeared. The first spark spectrum can be more easily studied than the arc spectrum, since the structure are on a very much bigger scale and more complete resolution can be attained. The present work is concerned with the spark lines excited in a hollow cathode discharge. Fine structures in iodine spark lines were first recorded long ago by Wood and Kimura who excited the lines in a Geissler tube and examined them with a transmission echelon. Murakawa attempted to analyse the fine structure data, but as the source and instrument employed by Wood and Kimura were not able to give the high resolution attained here, the deductions made from these data, although generally correct, are uncertain and require further examination; for many of the line structures are much more complex than as reported by these earlier observers.

scholarly journals The nuclear spin of arsenic

1932 ◽  
Vol 137 (833) ◽  
pp. 541-558 ◽  
Keyword(s):  
Fine Structure ◽  
Nuclear Spin ◽  
Ultra Violet ◽  
Resolving Power ◽  
Coupling Scheme ◽  
Vector Coupling ◽  
Theoretical Significance ◽  
Fine Structures ◽  
Multiplet Analysis ◽  
Interval Ratio

No fine structure has yet been recorded in any of the lines of the spectra of arsenic. The present paper gives an account of the fine structures of the majority of the visible lines of As II. This spectrum is very rich in strong lines and has been observed here in the region λλ 6400-4300 with high resolving power. The gross structure multiplet analysis of As II has been made by K. R. Rao, and the fine structure observations recorded here support this analysis. The terms expected and found in this spectrum are shown in Table I. All lines involving the 4 s 2 . 4 p 2 configuration lie in the deep ultra-violet region; therefore this configuration will be disregarded in the present investigation. According to the vector coupling scheme of White and Ritsehl it will be expected that the 4 s 2 . 4 p . 5 s configuration will show wide hyperfine structure separations, since it involves an unpaired penetrating s electron; this is actually verified here with some modification. As the 4 s 2 . 4 p . 5 p configuration has no penetrating s electron, only narrow structures are to be expected, but this, however, is not observed, since structures occur in this configuration which are of the same order as those found in the previous case. This has important theoretical significance and will be discussed later. The intervals in the 4 s 2 . 4 p . 5 s triplet terms which are 3 P 0 — 3 P 1 = 397 cm. -1 and 3 P 1 — 3 P 2 = 2382 cm. -1 show that the electron coupling is by no means pure (LS) since the interval ratio deviates widely from the Landé interval rule. In the 4 s 2 . 4 p . 5 p and in the 4 s 2 . 4 p 2 terms the deviations are much less marked. This incomplete (LS) coupling affects the structure and will be considered later.

scholarly journals High Time Resolution Photometry of Red Dwarf Flare Stars I. A Search For Fine Structures on the Optical Light Curves of Flares

1989 ◽  
Vol 104 (2) ◽  
pp. 95-97
Author(s):  
G.M. Beskin ◽  
S.N. Mitronova ◽  
S.I. Neizvestnyj ◽  
V.L. Plakhotnichenko ◽  
L.A. Pustil'nik ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Time Scales ◽  
Time Resolution ◽  
Light Curves ◽  
High Time ◽  
Special Astrophysical Observatory ◽  
High Time Resolution ◽  
Fine Structures ◽  
Flare Stars

AbstractA detailed analysis of 73 flares on UV Cet type stars observed at the 6 m telescope of the Special Astrophysical Observatory with 3x10–7 s time resolution shows no fine structures on flare light curves with time scales from 10–6 to 10–1 s.

scholarly journals On the role of evaporative wind in precataclysmic binaries (PCB)

1997 ◽  
Vol 180 ◽  
pp. 131-131
Author(s):  
I. Pustylnik ◽  
V. Pustynski
Keyword(s):  
Optical Depth ◽  
Black Body ◽  
Temperature Inversion ◽  
Light Curves ◽  
Gravitational Acceleration ◽  
Cool Component ◽  
First Results ◽  
The Mean ◽  
Absolutely Black Body ◽  
Definition Of

Recently we have started a systematic reevaluation of the existing observational methods of analysis hitherto applied to PCB-s. Here we report the first results of our investigations. The improved Napier's algorithm (Napier, 1968) to model the light curves of PCB (with the aid of the set of our computer programs in Turbo Pascal) is used. The source function is taken either from Sobieski (1965) or Strittmatter (1974). The entire luminosity received from the cool companion is calculated by integration of the emerging radiation over its disk; contributions from the illuminated and unilluminated portions of the disk are accounted for. We assume: a) the validity of the LTE in the photosphere of cool component, b) constancy of the monochromatic to mean absorption coefficient ratio within the photosphere, c) the hot star radiates as the absolutely black body, d) there are no other effects influencing the light curve except for the reflection effect. We have modelled the light curves of EC11575-1845 (Chen et al (1995). The analysis of the temperature distributions in the heated photosphere indicates the occurence of the temperature inversion. To make a rough estimate of physical conditions which can induce generation of evaporative wind we have used two criteria: i) the temperature inversion, ii) relation between radiative pressure and the effective gravitational acceleration. We assumed the density varies with the height in the atmosphere of the illuminated star as ρ ≃ exp(−Φ/RgT), Φ - being the Roche potential. The integral equation following from the definition of the mean optical depth was solved numerically to establish the relation between the mean optical depth and the distance in the atmosphere. We find the characteristic height scale for X-ray and EUV radiation is ∼ 106 − 107cm (for concentration of particles ∼ 1013cm−3). To check the validity of the ii) criterium we used a simplified model of radially expanding evaporative stellar wind and mass flux J conservation condition along the stream tube of the form J ∼ ρsvsrs2 exp −(Φ/RgT) (Pustylnik (1995)) and found M ∼ 10−12–10−11M/y. Although mass loss of such a rate cannot compete with the effects of the angular momentum loss which is responsible for a secular orbital shrinkage, the evaporative wind should significantly alter the structure of the the cool irradiated components.

scholarly journals Close-range remote sensing of Saturn’s rings during Cassini’s ring-grazing orbits and Grand Finale

Science ◽  
2019 ◽  
Vol 364 (6445) ◽  
pp. eaau1017 ◽  
Author(s):  
Matthew S. Tiscareno ◽  
Philip D. Nicholson ◽  
Jeffrey N. Cuzzi ◽  
Linda J. Spilker ◽  
Carl D. Murray ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Physical Properties ◽  
Optical Depth ◽  
Spectral Properties ◽  
Dynamical Processes ◽  
Ring Structures ◽  
Close Range ◽  
Saturn’S Rings ◽  
F Ring ◽  
Saturn's Rings

Saturn’s rings are an accessible exemplar of an astrophysical disk, tracing the Saturn system’s dynamical processes and history. We present close-range remote-sensing observations of the main rings from the Cassini spacecraft. We find detailed sculpting of the rings by embedded masses, and banded texture belts throughout the rings. Saturn-orbiting streams of material impact the F ring. There are fine-scaled correlations among optical depth, spectral properties, and temperature in the B ring, but anticorrelations within strong density waves in the A ring. There is no spectral distinction between plateaux and the rest of the C ring, whereas the region outward of the Keeler gap is spectrally distinct from nearby regions. These results likely indicate that radial stratification of particle physical properties, rather than compositional differences, is responsible for producing these ring structures.

scholarly journals Modelling of quiescent prominence fine structures

2013 ◽  
Vol 8 (S300) ◽  
pp. 59-68 ◽  
Author(s):  
S. Gunár
Keyword(s):  
Magnetic Field ◽  
Fine Structure ◽  
Radiative Transfer ◽  
Structure Formation ◽  
Current Status ◽  
Quiescent Prominence ◽  
Future Directions ◽  
The Future ◽  
Fine Structures ◽  
Transfer Modelling

AbstractWe review here the current status and the latest results of the modelling of quiescent prominence fine structures. We begin with the simulations of the prominence magnetic field configurations, through an overview of the modelling of the fine structure formation and dynamics, and with the emphasis on the radiative transfer modelling of the realistic prominence fine structures. We also illuminate the future directions of the field that lie in the combining of the existing approaches into more complex multi-disciplinary models.

Convergent Synthesis of the A—F Ring Segment of Yessotoxin and Adriatoxin.

ChemInform ◽  
2004 ◽  
Vol 35 (10) ◽  
Author(s):  
Isao Kadota ◽  
Hirokazu Ueno ◽  
Yoshinori Yamamoto
Keyword(s):  
Convergent Synthesis ◽  
Ring Segment ◽  
F Ring

scholarly journals Intensity measurements in a fine structure multiplet of As II

1934 ◽  
Vol 146 (859) ◽  
pp. 818-824 ◽  
Keyword(s):  
Fine Structure ◽  
Intensity Distribution ◽  
Nuclear Spin ◽  
Inherent Difficulty ◽  
Intensity Measurements ◽  
Fine Structures ◽  
Intensity Ratios ◽  
Instrumental Intensity ◽  
Spin Multiplet

The present work was undertaken with the object of testing the fine structure intensity formulæ deduced by Hill. Up to the present very few intensity measurements have been made on the fine structures arising from nuclear spin. The principal difficulty in such measurements arises from the smallness of the structures which are usually incompletely resolved by the interferometers employed. The use of the interferometer in any event necessitates careful corrections for the instrumental intensity distribution. Schüler and Keyston have made photometric determinations of the intensity ratios in the fine structures of two Cdl lines and have verified the intensity rules for these lines. An inherent difficulty in the examination with a FabryPerot interferometer of Cdl structures lies in the presence of an intense evei isotope line within the pattern due to the nuclear spin of the odd isotopes The even isotope component contributes 77% of the intensity of the line and the remaining 23% is distributed amongst the members of the nuclear spin multiplet. The authors do not describe their method of coping with this difficulty which, judging from the experience of the present writers, must have been serious.

scholarly journals Cyanine Dyes: Fine Structures in Their Absorption Spectra

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Anna Zarow ◽  
Yeung-gyo Shin
Keyword(s):  
Fine Structure ◽  
Absorption Spectra ◽  
Experimental Error ◽  
Cyanine Dyes ◽  
Electronic Coupling ◽  
Major Peak ◽  
Hydrocarbon Chains ◽  
Varying Length ◽  
Fine Structures ◽  
Intramolecular Process

Absorption spectra were studied for two series of 3 cyanine dyes with varying length of conjugated hydrocarbon chains. Fine structures in absorption spectra were analyzed to determine its concentration dependence as the concentration of dyes were changed from 10–8 M to 10–4 M. In all 6 dyes studied, ratios of minor peaks to the major peak remained constant within the experimental error. These results indicate that the origin of the absorption fine structure is due to the electronic coupling, an intramolecular process, rather than the aggregates formation, an intermolecular process.

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