The flare star PP Ori

We give the results of photographic, photoelectric, and spectral observations of the flare star PP Ori. The 109 photographic observations used, which were obtained on the 40 Schmidt telescope of the Byurakan Observatory over a period of about 20 years, and four spectra obtained on the same telescope with a4° objective prism show no variation in brightness. Photoelectric observations in the UBVR bands using the 50cm and 60cm telescopes of the high-altitude Maidanak station of the Tashkent Astronomical Institute in 1987 and 1989 give grounds for suspecting a variation in brightness much larger than observational errors. Spectral observations of the star PP Ori made on the 2.6m telescope of the Byurakan Observatory show weak H emission. The results of all these observations show that PP Ori is an Orion variable of spectral class K7-M0 with absolute visual magnitude7 ^m 5–8 ^m 5.Translated fromAstrofizika, Vol. 38, No. 2, 1995.     

Polarimetric and photometric observations of long-period variables

Observations of 35 long-period variables have been done mainly at the Byurakan Astrophysical Observatory during the last years. A polarimetric monitoring of 34 stars has been carried out with simultaneous photometric measurements for some of them. Photometric data in the UBVR bands have been obtained for the star Y Ori, which is the faintest one. The results show that the degree of light polarization is correlated with the period and brightness of these stars. This indicates that the degree of light polarization is connected with the mass loss as well. Finally the photoelectric observations of the stars Y Ori, T Cep, R Gem, and R Boo show a short-term increase of their brightness in the decreasing branch of their light curves. The measured (U-B) or (B-V) colors of detected rapid variations are bluer than the colors of the star measured before these events. It is supposed that the change of polarization with time, the relatively blue colors of miras near their minimum brightness, and the colors of detected rapid variations may be explained by the influence of a invisible blue companion, as in the case of the star R Aqr. Published in Astrofizika, Vol. 42, No. 3, pp. 341–350, July–September, 1999.     

New data on the variability of the spectrum of Kaz 163

The results of new spectral observations of the Seyfert component of the close binary galaxy with UV excess Kaz 163 are presented. Two new spectra have been obtained: with the 3-m telescope of Lick Observatory in 1986 and with the 1.8-m telescope of Asiago Observatory in 1993. It is shown that there was no short-term (about one month) variability in the spectrum. The emission lines Hell 4686 and Hel 5876 strengthen significantly between 1984 and 1986.Translated fromAstrofizika, Vol. 37, No. 1, pp. 5–12, January–March, 1994.     

The spectrum of the Cr star epsilon ursae majoris

Fourteen coudé spectrograms (eight with dispersion 12.4 Å mm^–1 and six 7 Å mm^–1) of the Cr star UMa (Ap) have been studied. The observations were made at the Haute Provence Observatory. The radial velocities of the various ions have been measured. The existence of Balmer progression in radial velocity is doubtful. The variability of some lines is in the opposite sense of K of Caii. Both a rough and a fine analysis have been made. The results of these analyses are compared and found to be in good agreement. The results of the fine analysis indicate a defect of Al, Si and Ca; Sc, Ti, Fe and Sr are normal, Mg and Ni are in slight excess. V, Cr and Mn are in excess by factors of 3, 12, 19; Y, Zr and Ba are in excess by factors of 9, 15, 30. Rare earths are in excess by factors ranging between 100–1000. These results are compared with the majority of the Cr–Eu–Sr stars.The observations have been made at the 152 cm coudé telescope of the Haute Provence Observatory.     

New Hα objects in dark nebulae. I.

Results of a search for new H objects in the Cepheus region are presented. The observations on which the search was based were made in 1979 and 1985 at the 40 Schmidt telescope of the Byurakan Astrophysical Observatory with a 4° objective prism. Of the 80 emission stars detected, 68 are new. Most of them are fainter than the sun in absolute magnitude. A large fraction of the emission stars discovered may be flare stars as well as T Tau and Herbig Ae/Be stars.Translated fromAstrofizika, Vol. 39, No. 1, pp. 57–65, January–March, 1996.     

Stochastic data in astronomy: Fourier analysis of highly nonuniform time series

The features of the CLEAN algorithm for Fourier analysis of time series with data separated by long pauses are analyzed in detail. Estimates are obtained for the limits of variability of the parameters of harmonic components that can be determined on a specified time grid. This analysis are used to search for harmonic components in the spectral line profile variations of the star Ori A (O8III) obtained in 2001 with the 1 m telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences.Translated from Astrofizika, Vol. 48, No. 1, pp. 87–100 (February 2005).     

New 115-1115-1115-1objects in dark nebulae. II.

Results of a search for new emission objects in the region of dark nebulae are presented. The observations were made in 1979 and 1985 at the 40 Schmidt telescope of the Byurakan Astrophysical Observatory. The spectra were obtained with a 4° objective prism (1100Å/mm near H) on Kodak 103aE, 103aF, IIaF, and IIIaF plates with the use of RG1 and RG2 filters. Of the 52 emission stars discovered, five show variability in the H line intensity.Translated fromAstrofizika, Vol. 38, No. 2, pp. 217–225, April–June, 1996.     

CCD BVI c observations of Cepheids

In 2008–2013, we obtained 11333 CCD BVI _c frames for 57 Cepheids from the General Catalogue of Variable Stars. We performed our observations with the 76-cm telescope of the South African Astronomical Observatory (SAAO, South Africa) and the 40-cm telescope of the Cerro Armazones Astronomical Observatory of the Universidad Católica del Norte (OCA, Chile) using the SBIG ST-10XME CCD camera. The tables of observations, the plots of light curves, and the current light elements are presented. Comparison of our light curves with those constructed from photoelectric observations shows that the differences between their mean magnitudes exceed 0?05 in 20% of the cases. This suggests the necessity of performing CCD observations for all Cepheids.     

Photometry of the Herbig Ae Star VV Ser B in an Anomalously Deep Brightness Minimum

Photopolarimetry of the classic Herbig Ae star VV Ser was carried out at the Crimean Astrophysical Observatory as a part of the longterm program of UX Ori type stars monitoring. An exceptionally deep minimum, down to V = 14^m8, was observed in 1998. For the first time for this star the blueing effect was detected in U – B and B – V color indexes. Record-high for UX Ori stars linear polarization (12.8 ± 1.4% in B) was observed in this minimum.     

Appearance of a nebula near Y Ori

The results of photographic and photoelectric observations for the star Y Ori are presented. During these observations a red nebulosity appeared around the star Y Ori near the maximum of brightness. The optical sizes of the nebulosity are comparable with the OH sizes of long period variables and OH/IR stars. A real brightness increase on the decreasing branch of the light curve was detected in U spectral band.Published in Astrofizika, Vol. 38, No. 4, pp. 555–558, October–December, 1995.     

The contact binary AE phoenicis — An analysis from deconvoluted spectra

A method is described for an analysis of deconvoluted stellar spectra, and applied to new spectroscopic observations of the close eclipsing system AE Phuenicis, obtained with the 1.52 m telescope of the Southern European Observatory at La Silla, Chile, Results are presented for the rotational velocities of this variable, together with a proposed model of the system.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia, 3–7 June, 1983.     

The SX Phe stars

A systematic photometry study of SX Phe stars together with high amplitude Sct stars have been carried out. Theuvbyß indices are obtained and the physical parameters are determined. The results obtained by using the pulsation and evolution theories independently are compared. A good agreement is found.Partially based on observations collected at European Southern Observatory, La Silla, Chile and by using the 1.5 m telescope from the Observatorio Astronómico Nacional (I. G. N.) at Calar Alto Observatory, Almería, Spain.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

New Hα-emission objects in the Cepheus region

Results are presented from a study of 31 new H -emission objects in the Cepheus region. The observations were performed with the 40 Schmidt telescope of the Byurakan Astrophysical Observatory in 1979, 1985, and 1989. Spectral plates were obtained with a 4° objective prism (-1100 Å/mm near H on Kodak 103-aE, 103-aF, III-aF and ORWO ZP-3 emulsions. Type RG1 and RG2 light filters were used during the observations.Translated from Astrofizika, Vol. 37, No. 2, pp. 219–228, April–June, 1994.     

The measurement of long-period oscillations at Sacramento Peak Observatory and South Pole

A program to measure long-period brightness oscillations at the solar limb has been pursued at Sacramento Peak Observatory for several years. Past improvements in observing technique and data analysis are reviewed. The encouraging results aid in the verification of the reality and the origin of oscillatory signals. However, the main stumbling block to this and other observational programs is the length of observing sequences imposed by the day/night cycle. The South Pole has received considerable attention as a site where extended observations might be possible. Currently, the Sacramento Peak program is developing a South Pole telescope designed for the observing technique and data analysis proven in Sunspot. A review of pertinent South Pole site parameters is given here for other workers who may be considering South Pole observations. Observing sequences longer than 150 hr are possible, though rare. Data sets of this duration are very attractive for solar oscillation studies.Proceedings of the 66th IAU Colloquium: Problems in Solar and Stellar Oscillations, held at the Crimean Astrophysical Observatory, U.S.S.R., 1–5 September, 1981.Operated by the Association of Universities for Research in Astronomy, Inc., under contract AST 78-17292 with the National Science Foundation.Summer Research Assistant at Sacramento Peak Observatory.     

Simultaneous multifrequency observations of an eruptive prominence at millimeter wavelengths

Radio images and spectra of an eruptive prominence were obtained from simultaneous multifrequency observations at 36 GHz, 89 GHz, and 110 GHz on May 28, 1991 with the 45-m radio telescope at Nobeyama Radio Observatory (NRO), the National Astronomical Observatory, Japan (NAOJ). The radio spectra indicated that the optical depth is rather thick at 36 GHz whereas it is thin at 89 and 110 GHz. The H data, taken at Norikura Solar Observatory, NAOJ, suggest that the eruption of an active region filament was triggered by an H flare. The shape and position of the radio prominence generally coincided with those of H images. The radio emission is explained with an isothermal cool thread model. A lower limit for the electron temperature of the cool threads is estimated to be 6100 K. The range of the surface filling factors of the cool threads is 0.3–1.0 after the H flare, and 0.2–0.5 in the descending phase of the eruptive prominence. The column emission measure and the electron number density are estimated to be of the order of 10²⁸ cm^–5 and 10¹⁰ cm^–3, respectively. The physical parameters of a quiescent prominence are also estimated from the observations. The filling factors of the eruptive prominence are smaller than those of the quiescent prominence, whereas the emission measures and the electron densities are similar. These facts imply that each cool thread of the prominence did not expand after the eruption, while the total volume of the prominence increased.     

Optical imaging of impact sites of Comet Shoemaker-Levy 9 at Bisei Astronomical Observatory

The impact sites of the Comet Shoemaker-Levy 9 are observed with the 101-cm telescope at Bisei Astronomical Observatory until the end of August with B, V, R, I, and methane-band (0.89m) filters. The outline of the observation is briefly described.     

The near infrared camera on the W.M. Keck telescope

The near infrared camera (NIRC) was used for a science demonstration run on the Keck telescope during 16–24 March 1993. The camera used a 256×256 InSb array manufactured by Santa Barbara Research Corporation. Observations were obtained using narrowband and broad band filters from 1 to 2.4 microns, and grisms with a spectral resolution of 0.6 percent in the J, H and K atmospheric windows. The instrument was fully background limited over the entire wavelength range. The sky background was quite low, reaching 14.3 mag/square arc sec in the broadband K _s filter. The image quality of the camera + telescope was excellent, being seeing limited in the range 0.5–0.9.The science demonstration observations of the NIRC on the Keck Telescope included observations of the most distant galaxy known, 4C41.17 at a redshift z=3.8 and the most luminous object known, the IRAS source FSC10214+4724 at a redshift z=2.29. Observations of the radio galaxy address the problem of the alignment effect in high redshift radio galaxies as well as the environments of such systems. FSC10214+4724 appears to be a merging galaxy that is at least 5×10⁸ years old.Based on observations obtained at the W.M.Keck Observatory, which is operated jointly by the California Institute of Technology and the University of CaliforniaThe W.M. Keck Observatory is operated as a scientific partnership between the California Institute of Technology and the University of California. It was made possible by the generous gift of the W.M. Keck foundation and the support of its president, Howard Keck.     

Independent estimate of the interstellar extinction toward FU Ori

Speckle-interferometric observations of FU Ori are performed with the 6-m telescope of the Special Astrophysical Observatory with 600/40 nm and 800/100 nm (central bandwidth/halfwidth) filters. The companion star FU Ori S that was recently discovered at λ >-1.25µm was recorded in observations with the λ/Δλ==800/100 nm filter. The positional parameters and magnitude difference of the companion in the filter considered are found to be θ = (163.9 ± 1.0)°, ρ = (0.493 ± 0.007)″, Δm = 3.96 ± 0.28. An analysis of the spectral energy distribution of the companion implies that for the extinction A _V toward FU Ori to be greater than about 1.6 ^m , i.e., the minimum value required by the available models of the fuor, the spectral type of the companion star must be no later than K3. The reliability of this conclusion and the possible ways for obtaining more accurate estimates of A _V are discussed.     

Epsilon Aurigae in eclipse: The light and colour variations

Theuvby andVRI observations of Aur during the ingress and early totality phases obtained at the McDonald Observatory are analysed. The light and colour variations of Aur during the 1982–1984 eclipse are compared with those found during the 1955–1957 eclipse.     

Column densities of Interstellar Gas in the direction of the starε Ori (B0 IA)

We have investigated the star Ori with IUE high resolution SWP spectrum in order to derive curve of growth and column densities of Al II, Si II, S II, Fe II, Ni II and Zn II. It has been possible to fit these ions on one empirical curve of growth with a velocity parameterb = 11 km s^–1 for the star studied.Based on observations made by the International Ultraviolet Explorer (IUE), and collected at the Villafranca Satellite Tracking Station of the European Space Agency.