CCD Polarimetric Imaging Of Comet Hale-Bopp (C/1995 O1)

Polarimetric observations of the light scattered by dust have been carried out at Pic-du-Midi Observatory with the 2 m telescope in June and September–October 1996, and at Haute-Provence Observatory with the 0.80 m telescope in April 1997. They cover a total number of 11 nights and a large (6.9°–47.7°) phase angle range. The spatial resolution allows to underline structures in the coma, as well in the brightness images as in the polarization maps, with a correlation between the regions of bright structures and the regions of higher polarization. A clear difference appears between the sunward and antisunward side, with higher polarization on the antisunward side. The phase angle coverage allows us to obtain a polarimetric phase curve for the whole coma and to compare it with other cometary phase curves. The degree of polarization is higher for Hale-Bopp than for the comets previously observed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Existence and Stability of L4,5 In The Relativistic Restricted Three-Body Problem

The existence and stability of triangular libration points in the relativistic restricted three-body problem has been studied. It is found that L_4,5 are unstable in the whole range 0 ≤ μ ≤ 1/2 in contrast to the classical restricted three-body problem where they are stable for 0 < μ < μ₀, where μ is the mass parameter and μ₀ = 0.03852.... This revised version was published online in July 2006 with corrections to the Cover Date.     

The Heliospheric Plasma Sheet Observed in situ by Three Spacecraft over Four Solar Rotations

Solar Physics - In this paper we present in&nbsp;situ observations of the heliospheric plasma sheet (HPS) from STEREO-A, Wind, and STEREO-B over four solar rotations in the declining phase of...     

Simultaneous UBVRI observations of the cataclysmic variable AE Aquarii: Temperatures and masses of fireballs

We report simultaneous multicolour observations in 5 bands (UBVRI) of the flickering variability of the cataclysmic variable AE Aqr. Our aim is to estimate the parameters (colours, temperature, size) of the fireballs that produce the optical flares. The observed rise times of the optical flares are in the interval 220‐440 s. We estimate the dereddened colours of the fireballs as (U ‐B)₀∼0.8‐1.4, (B ‐V)₀∼0.03‐0.24, and (V ‐I)₀∼0.26‐0.78. We find for the fireballs temperatures of 10000‐25000 K, masses of (7‐90)x10¹⁹ g, and sizes of (3‐7)x10⁹ cm (using a distance of d = 86 pc). These values refer to the peak of the flares observed in the UBVRI bands. The data are available upon request from the authors (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

N-Galaxies as a metagalactic population

Optical and radio data about N-galaxies (NG) as known at present are summarised and compared with the corresponding data about Seyfert galaxies (SyG), blue compact galaxies (BCG) and quasistellar objects (QSG and QSS). Information about normal galaxies and Haro and Markaryan objects is also utilized. The luminosity functions of different sources in the optical- and radio-ranges are constructed, based on the observational facts. Along with some general properties of NG and SyG, BCG, QSS and QSG, a number of differences between these objects are noted (these are summarised in Table II). In particularUBV-colours of NG and SyG change inside ring diaphragms for various diaphragm radii in quite different manners. Taking into account all these differences, it is concluded that N-galaxies are neither distant SyG nor QSS at small distances and therefore relatively weak, but are the representatives of a different metagalactic population.Arguments about the existence of stars in N-galaxies as well as a central central source of non-stellar nature are discussed. The question of possible evolutionary relations among the sequence of metagalactic populations Ir-S-E-D-(BCG-NG)-(QSG-QSS) is touched upon briefly.Translated from the Russian by D. F. Smith.     

On the asymmetry of moustaches

A careful photometry of moustaches is carried out to reveal asymmetry of their emission in the far wings ( 1 Å), if it exists. The presence of background continuous emission in spectra of moustaches demands special care with the photometry, and makes the current method of comparison of rest-intensities inadequate. The other sources of errors are also discussed. The blue asymmetry, as a systematic difference of intensities between the blue and the red wing shows itself in some cases, being 2–3 times larger than the probable errors. In most moustaches investigated, the accompanying background continuous emission shows a rapid increase to the violet.     

Grazing incidence spectra of the sun

Intensity calibrated grazing incidence spectrographs have been flown on three Skylark sounding rockets to record the solar soft X-ray and XUV spectra over a wide wavelength range. This paper describes the instrumentation and calibration procedures, and presents wavelength and intensity data, for each of the flights.     

Distribution and composition of suspended matter in water and snow cover in Kaliningrad Bay

Field data, collected by the authors during winter expedition studies in Kaliningrad Bay, are analyzed. Notwithstanding the presence of ice cover, considerable advective processes are shown to be taking place in the bay. Seawater enters the bay, spreading in the bottom horizon all over the water area. Suspended sediment concentration in under-ice period is on the average three times less than that in the ice-free period. The space and time variations of its quantitative and qualitative composition under ice are mostly governed by two factors—the effect of the sea and river runoff. The values of vertical fluxed of eolian material to the bay surface in winter vary from 0.5 to 2.9 with the average of 1.7 mg m^–2 day^–1.     

Operational requirements and the geometry of a station-keeping maneuver

In this paper station-keeping is regarded as the specialization of relative motion referred to a moving, orbiting origin. For this study a well-known linear solution to this problem serves as a base formulation from which the investigation begins.Even though the overall problem could be separated into three parts—necessitating two distinct studies for coverage—this paper examines only the last phase of the operation. That is, it is the continuation, or retention, of a relative motion sub-orbit which is of interest in this analysis.The situation becomes one of determining what is needed to maintain the sub-orbit, and/or to adjust it. In addition, the consequences of these actions, and the results predicted from theory are established, examined, and commented upon. In the presentation of information gathered from this study, various graphs have been prepared; however, these are expressed in a dimensionless format so that the results apply equally to all reasonable reference orbits.For this analysis the separate and combined influences, due to both the initial relative motion state and to a thrusting condition, are examined. Also, the consequences of referencing the acquired sub-orbits to an inertially aligned frame of reference (rather than the familiar rotating one) are illustrated, discussed, and commented upon.Formerly: Sr. Analyst and Manager, Seabrook Office, AMA, Inc., Seabrook, Md., U.S.A.