Authors:P. P. Petrov; E. V. Babina Pages: 1 - 8 Abstract: The T Tauri variable V1331 Cyg is characterized by an intensive emission spectrum, by signatures of a high rate of mass loss, and also by presence of a circular reflection nebula. According to these characteristics, the star can be considered as a possible pre-FUor star. Up to the present the photospheric spectrum of the star has not been recorded. In this work we analyze the high-resolution spectra of V1331 Cyg that were obtained by G.H. Herbig with the HIRES spectrograph at the Keck-1 telescope in 2004 and 2007. For the first time the numerous photospheric lines of the star have been detected and the spectral class has been estimated, viz., G7-K0 IV. It is revealed that the projection of the rotation velocity is lower than the width of instrumental profile (vsini < 6 km/s); this means that the angle between the stellar axis of rotation and the line of sight is small. The radial velocity of the star derived from the photospheric lines is RV = −15.0 ± 0.3 km/s. The difference in radial velocities for 2004 and 2007 is lower than the measurement error. The photospheric spectrum is veiled considerably, but the amount of veiling is not the same in different lines. This depends on the line strength in the template spectrum of the G7 IV star: in the weakest lines (EW = 5–10 mÅ in the template spectrum) VF ≈ 1 and it increases up to 4–5 in stronger lines. The Hα and Hβ lines demonstrate classical P Cyg profiles, which testifies to an intensive wind with a maximal velocity of about 400 km/s. In addition, the emission lines of Fe II, Mg I and K I and of several other elements are accompanied by a narrow blue-shifted absorption at −150...−250 km/s. The emission spectrum of V1331 Cyg is rich in the narrow (FWHM = 30–50 km/s) lines of neutral and ionized metals showing the excitation temperature T exc = 3800 ± 300 K. The stellar mass M* ≈ 2.8M ⊙ and radius R* ≈ 5R ⊙ are estimated. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010203 Issue No:Vol. 110, No. 1 (2014)
Authors:L. S. Lyubimkov Pages: 9 - 16 Abstract: The studies of the abundances of superheavy chemical elements in magnetic stars conducted at the Crimean Astrophysical Observatory were facilitated by the launch of the Astron space station in 1983. This spacecraft observed the ultraviolet spectra of such stars. The present brief review is focused on the abundances of superheavy elements (Pt, Au, Hg, Tl, Pb, Bi, Th, and U) in the atmospheres of magnetic Ap and HgMn stars. These results were obtained basing on the visible and ultraviolet spectra of stars. The data accumulated over more than 30 years show that these stars are characterized by significant overabundances (up to 6–7 dex) of such elements. The following important fact is noted: the superheavy element anomalies follow the trend in the anomalies that are characteristic of less heavy elements. Therefore, it may be assumed that all these anomalies (including the significant overabundances of superheavy elements) share a common explanation. Certain unresolved problems are discussed briefly. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010173 Issue No:Vol. 110, No. 1 (2014)
Authors:S. I. Plachinda Pages: 17 - 22 Abstract: This paper presents a brief history of the development of devices and techniques for high-precision measurements of stellar magnetic fields. Two main approaches for the processing of spectral-polarimetric observations are described: the method of least-squares deconvolution (LSD), which is used to find a mean-weighted average of the normalized polarization profile using a set of spectral lines, and a method in which each individual spectral line is used to determine the magnetic field, viz., the single line method (SL). The advantages and disadvantages of the LSD and SL methods are discussed. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010215 Issue No:Vol. 110, No. 1 (2014)
Authors:V. I. Marsakova Pages: 23 - 29 Abstract: The photometric properties of long-period variable stars and problems related to their traditional classification are analyzed. A general review of secular variations of such light-curve parameters studied in our previous papers as the period, amplitude, and mean brightness is given. Several types of Mira Ceti stars that differ in the secular period variation pattern are identified. A connection between the secular amplitude variations of certain variables with the effect of multiperiodicity is revealed. It is shown that the pattern of these variations and their numerical properties may be used to classify these variable stars. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010185 Issue No:Vol. 110, No. 1 (2014)
Authors:I. Yu. Alekseev; O. V. Kozlova Pages: 30 - 36 Abstract: The activity of the variable star IN Com is considered using the latest multicolor UBVRI photometry and linear polarimetric observations carried out during a decade. The photometric variability of the star is fully described using the zonal spottedness model developed at the Crimean Astrophysical Observatory (CrAO). Spotted regions cover up to 22% of the total stellar surface, with the difference in temperatures between the quiet photosphere and the spot umbra being 600 K. The spots are located at middle and low latitudes (40°–55°). The intrinsic broad-band linear polarization of IN Com and its rotational modulation in the U band due to local magnetic fields at the most spotted (active) stellar longitudes were detected for the first time. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010045 Issue No:Vol. 110, No. 1 (2014)
Authors:O. V. Kozlova; I. Yu. Alekseev Pages: 37 - 44 Abstract: We present long-term spectral observations (R = 20000) of IN Com in the region of the Hα, Hβ, and He I 5876 lines. One distinguishing characteristic of the stellar spectrum is the presence in the Hα line of an extended two-component emission with limits up to ±400 km/s. Emission parameters show the rotation modulation with the stellar rotation period and a significant variability on the long-term scale. Similar emissions are also observed in the Hβ and He I 5876 lines. Our results allow us to conclude that observational emission profiles are formed in an optically thin hot gas. This is a result of the presence of a circumstellar gas disk around IN Com. Its size does not exceed several stellar radii. The material for the disk is supported by the stellar wind from IN Com. The detected variability of Hα-emission parameters shows a clear connection with the photopolarimetric activity of the star. This fact allows us to associate the long-term spectral variability with cycles of stellar activity of IN Com. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010161 Issue No:Vol. 110, No. 1 (2014)
Authors:Yu. I. Neshpor; A. V. Zhovtan Pages: 45 - 49 Abstract: Based on the analysis of the published observational data on extragalactic and galactic sources in different energy ranges, it is concluded that there must be an emission generation phenomenon whereby the flux increases in a narrow energy range only, with higher-energy particles being more effectively accelerated. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010197 Issue No:Vol. 110, No. 1 (2014)
Authors:R. E. Gershberg Pages: 50 - 58 Abstract: Different aspects of stellar flares as one of the events of stellar activity with different levels of similarity to solar-activity phenomena are briefly discussed: those which are understandable by means of scaling of solar events, those that do not occur on the Sun but general solar features allow us to understand them, and such stellar events that have not been understood as yet. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010148 Issue No:Vol. 110, No. 1 (2014)
Authors:V. I. Burnashev; B. A. Burnasheva; E. V. Ruban; E. I. Hagen-Torn Pages: 76 - 79 Abstract: The absolute spectrophotometric catalog by Anita Cochran is presented in a machine-readable form. The catalog systematizes observations acquired at the McDonald Observatory in 1977–1978. The data are compared with other sources, in particular, the calculated broadband stellar magnitudes are compared with photometric observations by other authors, to show that the observational data given in the catalog are reliable and suitable for a variety of applications. Observations of variable stars of different types make Cochran’s catalog especially valuable. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010094 Issue No:Vol. 110, No. 1 (2014)
Authors:V. V. Butkovskaya Pages: 80 - 84 Abstract: For 60 years Vega has been accepted as a standard star in the near infrared, optical, and ultraviolet ranges. However, a 21-year spectral and spectrophotometric variability of Vega has been revealed. Vega also demonstrates short-term unexplained variability. Recent spectropolarimetric studies have revealed a weak magnetic field on Vega. We analyze the results of 15-year observations performed at the Crimean Astrophysical Observatory and we hypothesize that the magnetic field variation is caused by stellar rotation. In the present work we summarize the results of investigations on the variability of Vega. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010100 Issue No:Vol. 110, No. 1 (2014)
Authors:E. A. Baranovskii; S. A. Musorina; V. P. Tarashchuk Pages: 85 - 89 Abstract: Sunspot spectra for LiI 6708Å lines and for several FeI and CaI lines were obtained. Observations were performed in January and in August, 2011 using the TST-2 telescope with a charge-coupled camera at the Crimean Astrophysical Observatory. The sunspot models were calculated by using the observing profiles of FeI and CaI lines. Lithium abundance was determined by using the calculated sunspot models and LiI 6708Å observed profiles; this equals log(N Li) = 0.98 and 0.95 (in the scale logA(H) = 12.0). PubDate: 2014-06-01 DOI: 10.3103/s0190271714010069 Issue No:Vol. 110, No. 1 (2014)
Authors:O. S. Gopasyuk Pages: 90 - 94 Abstract: The rotation of sunspots in the solar active region NOAA 10930 was investigated on the basis of the data on the longitudinal magnetic field and the Doppler velocities using magnetograms and dopplergrams taken with the Solar Optical Telescope installed aboard the HINODE mission. Under the assumption of axial symmetry, areally-mean vertical, radial, and azimuthal components of the magnetic field and velocity vectors were calculated in both sunspots. The plasma in the sunspots rotated in opposite directions: in the leading sunspot, clockwise, and in the following sunspot, counterclockwise. The magnetic flux tubes that formed sunspots of the active region on the solar surface were twisted in one direction, clockwise. Electric currents generated as a result of the rotation and twisting of magnetic flux tubes were also flowing in one direction. Azimuthal components of magnetic and velocity fields of both sunspot umbrae reached their maximum on December 11, 2006. By the start of the X3.4 flare (December 13, 2006), their values became practically equal to zero. PubDate: 2014-06-01 DOI: 10.3103/s019027171401015x Issue No:Vol. 110, No. 1 (2014)
Authors:Z. S. Akhtemov Pages: 95 - 100 Abstract: This paper considers 3246 solar flares in the line Hα, which were accompanied by X-ray emission with a power f ≥ 5 × 10−6 Wm−2 in the solar cycle 22 (CR1797-CR1864). During 33 rotations, the specific power of X-ray emission of the flares increased monotonically by a factor of 4 from the cycle minimum up to its first maximum. The number of flares in each solar turnover rises non-monotonically and disproportionately to the relative number of sunspots. For the entire interval of time, one can identify several longitudinal intervals with increased flare activity. They exist during 5–10 rotations. The characteristics of the flares for 33 rotations in cycles 22 and 23 (CR1797-CR1961) are compared. It is concluded that the Sun is more active in cycle 22 than in cycle 23. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010021 Issue No:Vol. 110, No. 1 (2014)
Authors:E. A. Baranovskii; N. N. Kondrashova; M. N. Pasechnik; V. P. Tarashchuk Pages: 101 - 104 Abstract: Chromosphere layers of solar flares were investigated according to the observed profiles of the Hα line. A two-strand flare was observed on September 4, 1990. Spectra were obtained with the ATsU-26 solar horizontal telescope at Terskol Peak Observatory (3100 m). Spectra photometry is performed for two bright nodes of one strand of the flare. Some profiles are superposed to the ejection. The observed profiles are characterized by high emissions in the wings of the Hα line (up to 10–12 Å) under relatively low intensity in the center of Hα (r = 0.35–0.6). To explain such profile behavior we calculated flare models with two or three components. Separate components of the model correspond to unresolved details in the flare area and therefore the averaged profile is calculated. Emission in the far wings is explained by model components with deep heating of chromosphere layers. These occupy 5–12% of the total area. Noticeable emission asymmetry is explained by ray velocities of up to 70 km/s and more. The models are determined by agreement of the observed and calculated profiles. We processed several photometric profiles for seven observations. The temperature in the models with deep heating in the lower cromosphere is increased by 1000–2500 K with respect to the model with an undisturbed chromosphere VAL-C. The second feature of the observed profiles is their high asymmetry and shift with respect to the undisturbed profiles. This can be explained by the opposite motion of the material. We revealed that for the most of the profiles the line-of-sight velocities were directed to the observer in the upper chromosphere (10–100 km/s) and from the observer in the lower chromosphere (5–20 km/s). PubDate: 2014-06-01 DOI: 10.3103/s0190271714010070 Issue No:Vol. 110, No. 1 (2014)
Authors:A. N. Babin; A. N. Koval’ Pages: 105 - 113 Abstract: We analyzed the monochromatic Hα and spectral (within a range of 6549–6579 Å) observational data for the 2B/X6.9 flare of August 9, 2011, that produced emission in the optical continuum. The morphology and evolution of the Hα flare and the position, time evolution, spectrum, and energetics of the white-light flare (WLF) kernels were studied. The following results were obtained: the flare erupted in the region of collision of a new and rapidly growing and propagating magnetic flux and a preexisting one. This collision led to a merger of two active bipolar regions. The white-light flare had a complex structure: no less than five kernels of continuum emission were detected prior to and in the course of the impulsive flare phase. Preimpulsive and impulsive white-light emission kernels belonged to different types (types II and I, respectively) of white-light flares. A close temporal agreement between the white-light emission maxima and the microwave emission peak was observed for the impulsive white-light emission kernels. The maximum flux, luminosity, and total energy emitted by the brightest impulsive WLF kernel equaled 1.4 × 1010 ergs cm−2 s−1, 1.5 × 1027 ergs/s, and 5 × 1029 ergs, respectively. The Hα profiles within the impulsive WLF kernels had broad wings (with a total extent of up to 26 Å and a half-width of up to 9 Å) and self-reversed cores. The profiles were symmetrical, but were shifted towards the red side of the spectrum. This is indicative of a downward motion of the entire emitting volume with a radial velocity of several tens of km/s. The intensity pattern in the wings did not correspond to the Stark one. The profiles were broadened by nonthermal turbulent motions with velocities of 150–300 km/s. The observed Hα profiles were analyzed and compared in their features to the profiles calculated for an intense heating of the chromosphere by nonthermal electrons accompanied by the development of a chromospheric condensation propagating downward. We came to the conclusion that the analyzed flare exhibited spectral features that may not be readily explained within the framework of chromosphere heating by a beam of nonthermal electrons. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010057 Issue No:Vol. 110, No. 1 (2014)
Authors:Z. S. Akhtemov; O. A. Andreeva; G. V. Rudenko; N. N. Stepanian; V. G. Fainstein Pages: 114 - 124 Abstract: Calculations of the magnetic field in the potential approximation (using Bd technology (Rudenko, 2001)) were used to study the time variations of several parameters of the large-scale magnetic field in the solar atmosphere during the last four cycles. Synoptic maps (SMs) for the radial component Br of the calculated magnetic field were plotted at 10 heights between the solar surface (R = R ⊙) and the source (R = 2.5R ⊙). On these SMs, we marked the 10-degree latitudinal areas. The following (averaged within the zone) characteristics of the magnetic field were determined corresponding to these zones: Sp, Sm; S +fields , where Sp is the positive value of Br, Sm is the averaged modulus of the negative Br; S +fields is the percentage of latitudinal zones with positive Br. The analysis of temporal variations in the magnitude of S points to different origins of the large-scale magnetic field in the near-equatorial and polar regions of the solar atmosphere. The analysis of temporal variations of S +fields showed that there were almost no periods with a mixed polarity at R = 2.5R ⊙ during the 21st and 22nd solar cycles and in an ascending phase of the 23rd cycle. However, beginning from the maximum of the 23rd cycle, a mixed polarity in the equatorial region was observed until the end of the long minimum of activity. We hypothesized that this could be a precursor for a long minimum between the 23rd and 24th solar cycles. It was shown that during the maximum phase of the 24th solar cycle the magnetic field at R = R ⊙ is much less than that during the maximum phase of the 23rd cycle, and in the region from 55° to 75°, this difference reaches an order of magnitude. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010033 Issue No:Vol. 110, No. 1 (2014)
Authors:Yu. A. Fursyak Pages: 125 - 131 Abstract: We analyzed the data on the flares of the X-ray class X in the 24th solar activity cycle. Several properties of the active regions (their morphological structure, the changes in the structure of the magnetic fields of spots, the evolution dynamics, etc.) were also analyzed with the object of identifying the factors that influence the flare activity of a group the most. In order to gather the maximum amount of experimental data, we used the observational data that cover various levels of the solar atmosphere that were obtained both by terrestrial and space (SOHO, SDO, XRT, Hinode, etc.) telescopes. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010136 Issue No:Vol. 110, No. 1 (2014)
Authors:V. Yu. Terebizh Pages: 132 - 137 Abstract: A compensator (null-corrector) for testing aspheric optical surfaces is proposed, which enables (1) independent verification of optical elements and assembling of the compensator itself, and (2) ascertaining the compensator position in a control layout for a specified aspheric surface. The autocollimating design allows significant reducing difficulties associated with practical use of lens compensators. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010239 Issue No:Vol. 110, No. 1 (2014)
Authors:A. V. Dolgopolov Pages: 146 - 148 Abstract: A mechanical design of a fast wide-field telescope with an entrance pupil that is 180 mm diameter, a focal length of 294 mm, and an angular field of view of 10° is described. Original construction solutions have been found for this type of system. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010112 Issue No:Vol. 110, No. 1 (2014)
Authors:N. N. Stepanian; G. A. Sunitsa; V. M. Malashchuk Pages: 149 - 160 Abstract: Questions of the mounting and adjustment of a tower solar telescope are considered through the example of the TST-2 telescope of the Crimean Astrophysical Observatory Scientific Research Institute. The authors describe the optical circuits of the telescope and spectrograph and list the basic requirements for the mutual arrangement of individual components of the telescope. Simple methods for adjusting elements of the telescope and spectrograph are described. PubDate: 2014-06-01 DOI: 10.3103/s0190271714010227 Issue No:Vol. 110, No. 1 (2014)
Hybrid journal (It can contain Open Access articles)
[2355 journals]
