Analysis of the nonstationarity of the atmosphere of α Cyg. III. Variability of the Hα-line profile

The temporal variations of the radial velocity and profile of the Hα line in the spectrum of α Cyg are analyzed based on 240 CCD spectra taken with the coude spectrograph attached to the 2-m telescope of Shamaha Astrophysical Observatory of the National Academy of Sciences of Azerbaijan in 1998–2000. The results obtained are inconsistent with the conclusion made by the Heidelberg group concerning the behavior of the variability of the Hα-line profile [1]. The observed pattern of radial-velocity variations is due to nonradial pulsations and differs for the blue and red halves of the absorption profile. The pulsation parameters differ for different levels of residual intensity for both halves of the absorption profile. The amplitude and period increase from the core toward the wing of the line for the red half of the absorption profile, and, on the contrary, decrease toward the line wing for the blue half of the profile. Absorption features are observed on the blue half of the absorption profile. Their emergence and disappearance, as well as minor migrations are indicative of the clumpy structure of the stellar envelope. The similarity of the variability behavior of the absorption and emission profiles indicates that the latter too owe their variability to nonradial pulsations. Thus the variability of the stellar wind in its formation regions is partly due to the nonradial pulsations of the underlying layers of the atmosphere. On the whole, the variability of the position and photometric parameters of the absorption and emission components of the profile is indicative of the nonstationary nature and asymmetric shape of the stellar wind.     

Speckle interferometry of magnetic stars with the BTA. II. Results of 2010–2012 observations

We present the results of speckle interferometric observations of 156 stars possessing global magnetic fields, carried out with the 6-m BTA telescope of the Special Astrophysical Observatory. Virtually all stars were observed between 2010 and 2012. Thirty-four stars were resolved into individual components (31 double and 3 triple), of which 14 binary systems (BD+41○43, HD2887, HD30466, HD36540, HD36955, HD37479, HD61045, HD89069, HD144334, HD164258, HD349321, HD343872, HD184471, HD196691) and 2 triple systems (HD37140, HD338226) were for the first time resolved by the astrometric method.     

Multi-frequency survey of background radiations of the Universe. The “Cosmological Gene” project. First results

The results of the first stage of the “Cosmological Gene” project of the Russian Academy of Sciences are reported. These results consist in the accumulation of multi-frequency data in 31 frequency channels in the wavelength interval 1–55 cm with maximum achievable statistical sensitivity limited by the noise of background radio sources at all wavelengths exceeding 1.38 cm. The survey region is determined by constraints 00 ^h < RA < 24 ^h and 40°30′ < DEC < 42°30′. The scientific goals of the project are refined in view of recent proposals to use cosmological background radiation data for the development of a unified physical theory. Experimental data obtained with the RATAN-600 radio telescope are used to refine the contribution of the main “screens” located between the observer and the formation epoch of cosmic background radiation (z = 1100). Experimental data for synchrotron radiation and free-free noise on scales that are of interest for the anisotropy of cosmic microwave background are reported as well as the contribution of these noise components in millimeter-wave experiments to be performed in the nearest years. The role of dipole radio emission of fullerene-type dust nanostructures is shown to be small. The most precise estimates of the role of background radio sources with inverted spectra are given and these sources are shown to create no serious interference in experiments. The average spectral indices of the weakest sources of the NVSS and FIRST catalogs are estimated. The “saturation” data for all wavelengths allowed a constraint to be imposed on the Sunyaev-Zeldovich noise (the SZ noise) at all wavelengths, and made it possible to obtain independent estimates of the average sky temperature from sources, substantially weaker than those listed in the NVSS catalog. These estimates are inconsistent with the existence of powerful extragalactic synchrotron background associated with radio sources. Appreciable “quadrupole” anisotropy in is detected in the distribution of the spectral index of the synchrotron radiation of the Galaxy, and this anisotropy should be taken into account when estimating the polarization of the cosmic microwave background on small l. All the results are compared to the results obtained by foreign researchers in recent years.     

Origin of Mercury’s double magnetopause: 3D hybrid simulation study with A.I.K.E.F.

During the first and second Mercury flyby the MESSENGER spacecraft detected a dawn side double-current sheet inside the Hermean magnetosphere that was labeled the “double magnetopause” (Slavin, J.A. et al. [2008]. Science 321, 85). This double current sheet confines a region of decreased magnetic field that is referred to as Mercury’s “dayside boundary layer” (Anderson, M., Slavin, J., Horth, H. [2011]. Planet. Space Sci.). Up to the present day the double current sheet, the boundary layer and the key processes leading to their formation are not well understood. In order to advance the understanding of this region we have carried out self-consistent plasma simulations of the Hermean magnetosphere by means of the hybrid simulation code A.I.K.E.F. (Müller, J., Simon, S., Motschmann, U., Schüle, J., Glassmeier, K., Pringle, G.J. [2011]. Comput. Phys. Commun. 182, 946–966). Magnetic field and plasma results are in excellent agreement with the MESSENGER observations. In contrast to former speculations our results prove this double current sheet may exist in a pure solar wind hydrogen plasma, i.e. in the absence of any exospheric ions like sodium. Both currents are similar in orientation but the outer is stronger in intensity. While the outer current sheet can be considered the “classical” magnetopause, the inner current sheet between the magnetopause and Mercury’s surface reveals to be sustained by a diamagnetic current that originates from proton pressure gradients at Mercury’s inner magnetosphere. The pressure gradients in turn exist due to protons that are trapped on closed magnetic field lines and mirrored between north and south pole. Both, the dayside and nightside diamagnetic decreases that have been observed during the MESSENGER mission show to be direct consequences of this diamagnetic current that we label Mercury’s “boundary-layer-current“.     

Comments on ‘the equation of polarization transfer in an inhomogeneous magnetized plasma. I. Formalism’ by F.T. Cheng and P.C.W. Fung

In their discussion of the transfer of polarized radiation in a weakly anisotropic, weakly inhomogeneous plasma, Cheng and Fung (1977) have included terms which describe the effects of mode coupling and of the variation of the characteristic polarizations. The latter effect is nonphysical, and only the mode-coupling term should be retained. As the problem was formulated by Cheng and Fung, the two terms would cancel exactly; consequently, when corrected, the work of Cheng and Fung leads to a simple and useful method of including the effects of mode coupling in the weak anisotropy limit.On leave from Department of Theoretical Physics, Faculty of Science, Australian National University.     

Speckle interferometry of nearby multiple stars. V. 2002–2006 positional measurements

We present the measurements of positional parameters of 194 nearby binary stars performed at the 6-m BTA telescope of the SAO RAS from 2002 through 2006 applying the speckle interferometric technique. The observations were conducted at central filter wavelengths ranging from 545 to 800 nm using a speckle interferometer equipped with a fast CCD and a three-stage image intensifier. A significant part of the observed systems (80 stars) are pairs, the duality of which was discovered or suspected from the Hipparcos satellite observations. The remaining stars are visual binaries and interferometric binary systems with orbital motion period estimates from several to tens of years, as well as the pairs with slow relative motion of the components, used for gaging the image scales and positional angle calibrations.     

Rhombic Cell Analysis - A New Way of Probing the Large- Scale Structure of the Universe. I.General Considerations

A new way of probing the harge-scale structure of the universe is proposed.Space is partitioned into cells the shape of rhombic dodecahedron.The cells are labelled “filled“ or “empty“ according as they contain galaxies or not ,the cell size is so chosen as to have narly equal numbers of filled and empty cells for the given galaxy sample.Two observables on each cell are definable:the number of ist like neighbors,n1,and a two-suffixed topological type τ,the suffixes being the numbers of its like and unlike neighbor-groups.The frequency distributions of n1 and τ in the observed set of filled(empty)cells are then considered as indicators of the morphology of the set,The method is applied to the CfA catalogue of galaxies as an illustration.Despite its limited size,the data offers evidence 1) that the empty cells are more stongly clustered than the filled cells,and 2) theat the filled cells,but not the empty cells,have a tendency to occur in sheets,Further directions of development both in theory and application are indicated.     

Asteroids,comets, meteoric matter: Proceedings of the IAU Colloquium No. 22, held at the University of Nice,France, April 4–6, 1972. Edited by C. Cristescu,W. J. Klepczynski,and B. Milet. Acad. Rep. Soc. Romania,Bucharest, 1974. 333 pp., 27 L

A model is proposed for single close encounters between two small masses, m₁and m₂, which orbit a much larger mass, M. The main new feature of the model is the assumption of conic motion of the center of mass of m₁and m₂ in the gravitational field of M. Comparisons of the model with the three-body equations of motion indicate that the model is a useful approximation for m₁, m₂ ? 10^?5M. The model is therefore applicable for encounters between bodies of the order of an earth mass or smaller in the presence of the sun. Comparisons are also made of outcomes obtained by the model with outcomes of numerical integration for a large variety of close encounters. The above comparisons reveal that for many purposes the model is an adequate approximation for those encounters with ? ≥ 4, where ? is the eccentricity of the hyperbolic orbit of m₁about m₂.     

Investigation of Galaxies of the Second Byurakan Sky Survey. V. Spectroscopic Observations in the Field of 12h22m, +55°

The results of spectroscopic observations of 28 galaxies of the Second Byurakan Sky Survey, completing the follow-up spectroscopy of galaxies in the survey field with central coordinates = 12^h22^m, = +35°, are presented. The spectra were obtained on the 2.6 m telescope of the Byurakan Astrophysical Observatory, National Academy of Sciences of the Republic of Armenia, and the 6 m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences. The redshifts and absolute stellar magnitudes of all the galaxies have been determined. A preliminary analysis of the spatial distribution of all galaxies in this sample is given.     

Measurement of Kodaikanal white-light images – IV. Axial Tilt Angles of Sunspot Groups

The Kodaikanal sunspot data set, covering the interval 1906–1987, is used in conjunction with the similar Mount Wilson sunspot data set, covering the interval 1917–1985, to examine characteristics of sunspot group axial tilt angles. Good agreement is demonstrated between various results derived from the two independent data sets. In particular, the tendency for sunspot groups near the average tilt angle to be larger than those far from the average tilt angle is confirmed. Similarly the faster residual rotation rate for groups near the average tilt angle is also confirmed. Other confirmations are made for the relationships between latitude drift of sunspot groups and tilt angle, polarity separations, and axial expansion. Evidence is presented that tilt angles averaged over these long time intervals differ between the north and south hemispheres by about 1.4 deg. It is suggested that residual tilt angles show a slight systematic variation with phase in the activity cycle.     

Comments on ‘outward transport of angular momentum...’ by E. M. Drobyshevski

Drobyshevski's effect for maintaining the equatorial acceleration of the Sun is characterized to be of order/R where represents the eddy size andR the solar radius. The weakness of this mechanism is, therefore, not surprising.Furthermore we have discussed the idea of replacing the two-dimensional eddy tubes by spherical eddy configurations. We can state here that a theory which is linear in the rotational rate and uses the radial direction as the only source (besides) of anisotropy cannot explain the observed phenomenon of differential rotation.     

Making Sense of Sunspot Decay. I. Parabolic Decay Law and Gnevyshev–Waldmeier Relation

In a statistical study of the decay of individual sunspots based on DPR data we find that the mean instantaneous area decay rate is related to the spot radius r_o and the maximum radius r_o as D = C_D r/r_o, C_D = 32.0±0.26 MSH day ^-1. This implies that sunspots on the mean follow a parabolic decay law; the traditional linear decay law is excluded by the data. The validity of the Gnevyshev–Waldmeier relationship between the maximum area A ₀ and lifetime T of a spot group, A₀/T 10 MSH day^-1, is also demonstrated for individual sunspots. No evidence is found for a supposed supergranular quantization of sunspot areas. Our results strongly support the recent turbulent erosion model of sunspot decay while all other models are excluded.     

Martian occultation of ϵ Gem as observed from the C. E. Kenneth Mees observatory

Ground-based observations of the occultation of ? Gem by Mars on April 8, 1976 have been reduced in the manner of French et al. [Icarus 33, 186–202 (1978)] to yield the scale height and temperature profiles of the Martian atmosphere for number densities between 10¹³ and 10¹⁵ cm^?3. The deduced variations in temperature are remarkably similar to those obtained by Elliot et al. [Astrophys. J.217, 661–679 (1977)] and to the in situ measurements from the Viking landers.     

Panoramic spectroscopy of galaxies with star-formation regions. a study of SBS 1202?+?583

The methods of panoramic (3D) spectroscopy are used by us in a detailed study of galaxies with ongoing star formation chosen from among objects in seven selected fields of the Second Byurakan Survey (SBS). This article deals with the irregular galaxy SBS 1202 + 583, which our classification scheme identifies as being in a continuous phase of star formation. Observations were made with the panoramic spectrographs MPFS at the 6-m telescope of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences and VAGR at the 2.6-m telescope of the Byurakan Astrophysical Observatory (BAO) in Armenia. The data are used to construct maps of the radiative fluxes in the continuum and various emission lines. Special attention is devoted to analyzing the emission in the Hα hydrogen recombination line and in the forbidden low-ionization doublets of nitrogen [NII] λλ6548, 6583 and sulfur [SII] λλ6716, 6731, and the ratios of the intensities of the forbidden lines to Hα. The observable characteristics (size, Hα fluxes, etc.) of nine HII regions are studied. The estimated current rates of star formation in the individual HII regions based on the Hα fluxes lie within the range of 0.3-1.2_⨀ M /year. The dependence of the ratio of the intensities of the emission in these above mentioned forbidden doublets on the rate of star formation in the HII regions is found.