Disc system delta Capricorni

FirstUBV photoelectric photometry of the eclipsing binary system Cap has been presented. An improved period of 1^d.022766 has been given. The duration of primary eclipse comes out to be more than double the duration given earlier. The depth has also been found to have increased. The light changes during eclipses show slight asymmetry. Eccentricity appears to be present in the system. Light and colour curves show variations. Primary component appears to be surrounded by a disc, the size of which is comparable to the size of the primary component. Two dips are seen around phases 0.20 and 0.67, the first appears more definitive, and is attributed to the wave-like distortion, like the one found in RS CVn binaries. The discussion reveals that Cap is a very complicated system.     

Spectrophotometric observations of delta Capricorni

Spectrophotometric observations of the eclipsing binary system Capricorni, covering the wavelength interval 3300–7300 Å, have been presented. Comparison of the standard spectral scans of Cap with the spectral scans of the stars of known spectral types and luminosity classes taken from the Breger (1976) catalogue shows that, near the phase of secondary eclipse, Cap shows the spectral-luminosity type as A8-9III. This is in agreement with the photometric findings of Srivastava (1987b). H emission is not visible convincingly, however, some irregularities are apparent, at least in two scans, around the H region.     

Detailed study of B037 based on HST images

B037 is of interest because it is both the most luminous and the most highly reddened cluster known in M31.Deep observations and high spatial resolution images with the Advanced Camera for Surveys on the Hubble Space Telescope(HST) first showed that this cluster is crossed by a dust lane.Photometric data in the F606W and F814W filters obtained in this paper indicate that colors of(F606W-F814W) in the dust lane are redder-0.4 mag than ones in the other regions of B037.The HST images show that this dust lane ...     

A study of the variability of the Delta Scuti-stars

A total of 321 observations of the Delta Scuti star BD –6°4932, obtained in 1968 by Hall and Mallama (1970), are analyzed. We find four frequencies which represent the light curves satisfactorily.The three periods:P ₁=0 _. ^d 240,P ₃=0 _. ^d 182 andP ₄=0 _. ^d 114 seem to correspond to the radial modes of pulsation withK=0, 1, and 3, respectively. The last periodP ₂=0 _. ^d 220 can be related to a non-radial mode.     

A period study of V450 Herculis

A detailed period study of the eclipsing binary system V450 Her has been presented. A new period (P= _. ^d 12724) has been given. The period changes in different portions of the O-C diagram, based on new period, have been estimated. The total period change ranges from 3.28×10^–6 d to 7.06×10^–5 d, which is appreciable.     

A study of the variability of the Delta Scuti stars

More than 1700 photmetricV observations of the Delta Scuti HR 2557, obtained at the Merate Observatory during the two periods: 1979–80 and 1981, are analyzed. In spite of the fact that the sets of frequencies for the two periods are similar, the interpretation of these oscillations is far to be satisfactory. The lowest frequencies can be reasonably interpreted as corresponding to the lowest radial modes. Unfortunately, nothing can be said about the highest frequencies.     

Detailed analysis of cool stars

We present the detailed analysis of fourteen cool stars, nine of which have been associated by Eggen with four moving groups from the kinematics and the photometric properties; the five remaining stars are characterized by a large-spatial velocity. From the scatter of the chemical composition among the program stars belonging to a same group, we discuss that the moving groups Her, Wolf 630, and Kapteyn could really exist, and that Groombridge 1830 do not. No peculiar abundance relative to iron is found except a possible relative overabundance of Ni for the most metal-poor stars in this sample. The results of the detailed analyses are discussed in terms of the chemical abundances of our Galaxy.Based on observations collected at European Southern Observatory, La Silla, Chile and Observatoire de Haute-Provence, France.     

First light curve and period study of LO Andromedae

New BV light curves and times of minimum light for the short period W UMa system LO And were analyzed to derive the preliminary physical parameters of the system. The light curves were obtained at Ankara University Observatory during 5 nights in 2003. A new ephemeris is determined for the times of primary minimum. The analysis of the light curves is made using the Wilson‐Devinney 2003 code. The present solution reveals that LO And has a photometric mass ratio q = 0.371 and is an A‐type contact binary. The period of the system is still increasing, which can be attributed to light‐time effect and mass transfer between the components. With the assumption of coplanar orbit of the third body the revealed mass is M₃ = 0.21M_⊙. If the period change dP/dt = 0.0212 sec/yr is caused only by the mass transfer between components (from the lighter component to the heavier) the calculated mass transfer rate is dm/dt = 1.682×10⁻⁷M_⊙/yr. The absolute radii and masses estimated for the components, based on our photometric solution and the absolute parameters of the systems which have nearly same period are R₁ = 1.30R_⊙, R₂ = 0.85R_⊙, M₁ = 1.31M_⊙, M₂ = 0.49M_⊙ respectively for the primary and secondary components. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Detailed study of the Ursa Major supercluster of galaxies using the 2MASS and SDSS Catalogs

We study the infrared (K _s band) properties of clusters of galaxies in the Ursa Major supercluster using data from 2MASS (Two-Micron All-Sky Survey) and SDSS (Sloan Digital Sky Survey). We identified three large filaments with mean redshifts of z = 0.051, 0.060, and 0.071. All clusters of the supercluster are located in these filaments. We determined the total K _s-band luminosities and masses for 11 clusters of galaxies within comparable physical regions (within a radius R ₂₀₀ close to the virial radius) using a homogeneous method. We constructed a combined luminosity function for the supercluster in this region, which can be described by the Schechter function with the following parameters: M _K ^* = ?24.50 and α = ?0.98. The infrared luminosities of the clusters of galaxies correlate with their masses; the M/L _K ratios of the systems increase with their masses (luminosities), with most of the Ursa Major clusters of galaxies (particularly the richer ones) closely following the relations derived previously for a large sample of clusters and groups of galaxies. The total mass-to-infrared-luminosity ratio is 52 M _⊙/L _⊙ for six Abell clusters and 49M _⊙/L _⊙ for all of the clusters, except Anon2.     

The new light curves and period study of AK Herculis

B andV observations of the W Ursae Majoris-type eclipsing variable system AK Her were made on five nights at the Ege University Observatory. Several times of minima were obtained during the observations and the new light elements were calculated. The light-time period was found to be about 75.72 years. The light curve of the system appears to change in each cycle for both colours. The secondary minimum of the system seems to be a total eclipse with a duration of about 42 ^m .5.     

Photoelectric UBV observations and period study of AK Herculis system

New photoelectric UBV observations of the W Ursae Majoris-type eclipsing binary AK Her are presented. The system exhibits many phenomena such as O'Connell effect, unequal depth, phase shift and different duration in secondary eclipse due to its totality, which have been studied. O'Connell effect-duration relation may be exist. The (O-C) curve has been obtained and the new light elements have been calculated. The analysis of the minima-times data of the system reveals possible sinusoidal orbital period variation (LITE). The study of the (O-C)curve, the light curves, O'Connell effect and the duration effect have led to that the system is likely a case which undergoes cyclic around the marginal contact state conservatively with mass transfers between its components, i.e.in TRO mode. This revised version was published online in July 2006 with corrections to the Cover Date.     

Detailed isophotometry of some galaxies,I

Results from a detailed isophotometric survey of NGC 5595, NGC 5597, NGC 5605, and NGC 7769 are given. It includes isophotic maps, luminosity profiles and ellipticity curves as well. Scanning of these galaxies was done in theB andV colours.     

On the dynamics in the asteroids belt. Part II: Detailed study of the main resonances

The general theory exposed in the first part of this paper is applied to the following resonances with Jupiter's motion : 3/2, 2/1, 5/2, 3/1, 7/2, 4/1; these are the most relevant resonances for the asteroids. The whole analysis is performed in the framework of the spatial problem of three bodies, both in the circular and in the elliptic case. The results are also compared with the observed distribution of the asteroids.     

A comprehensive study of reported high-metallicity giant H ii regions – I. Detailed abundance analysis

We present long-slit observations in the optical and near-infrared of 14 H  ii regions in the spiral galaxies NGC 628, 925, 1232 and 1637, all of them reported to have solar or oversolar abundances according to empirical calibrations. For seven of the observed regions, ion-weighted temperatures from optical forbidden auroral to nebular line ratios are obtained and, for six of them, the oxygen abundances derived by standard methods turn out to be significantly lower than solar. The other one, named CDT1 in NGC 1232, shows an oxygen abundance of     , and constitutes, to the best of our knowledge, the first high-metallicity H  ii region for which accurate line temperatures, and hence elemental abundances, have been derived.
For the rest of the regions no line temperature measurements could be made, and the metallicity has been determined by means of both detailed photoionization modelling and the sulphur abundance parameter S ₂₃. Only one of these regions shows values of O ₂₃ and S ₂₃ implying a solar or oversolar metallicity.
According to our analysis, only two of the observed regions can therefore be considered as of high metallicity. These two fit the trends previously found in other high-metallicity H  ii regions, i.e., N/O and S/O abundance ratios seem to be higher and lower than solar respectively.     

Detailed abundances of rare earth elements,thorium and uranium in chondritic meteorites: An ICP-MS study

Abstract— Inductively coupled plasma mass spectrometry (ICP-MS) was successfully applied to bulk samples of Allende, Jilin, Modoc, Saint-Séverin and Atlanta for the determination of rare earth elements (REE) (Y and 14 lanthanoids), Th and U. The results of ICP-MS showed good agreement with recommended values, and their reproducibilities were high enough to discuss the detailed abundances of lanthanoids and actinoids in chondritic meteorites. For the Allende reference sample issued by the Smithsonian Institution, a positive anomaly of Tm, a fractionation between light REE and heavy REE and a high Th/U ratio were observed in the CI-normalized abundances of REE, Th and U. These features are common for group II inclusions in Allende, suggesting that the abundances of refractory lithophiles in Allende are somewhat influenced by those in a specific constituent. For the other chondritic meteorites, a zigzag alteration was commonly observed in the heavy-REE region of their CI-normalized abundance patterns. It is suggested that such a zigzag pattern is attributable to erratically high abundances of monoisotopic REE (Tb, Ho and Tm) in the CI values. Abundances of REE, Th and U in the bulk samples are also discussed separately in detail.     

Light and period study of the ecipsing binary system TW Andromedae

Photoelectric light curve (LC) solutions of the close binary system TW And were obtained using the PHOEBE program (version 0.31a). Absolute parameters of the stellar components were then determined, enabling us to discuss the structure and evolutionary status of TW And. The configuration of the system based on the LCs solutions indicates that the secondary component is slightly detached from its critical Roche surface. In addition, times of minima data (“O –C curve”) were analyzed. Apart from an almost parabolic variation of the general trend of the O –C data, indicative of a secular increase in the orbital period with a rate 0.032 s yr^–1, which was attributed to a mass transfer with a rate of Δm₂ = –1.10 × 10^–10 M_⊙ yr^–1. Additionally, a sinusoidal variation with a period of 52.75 ± 1.80 yr, modulating the orbital period, was found, which we attribute to a third body orbiting the system. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

New period study of the eclipsing binary V865 Cygni

Several new precise times of minima, based on CCD observations, have been secured for the relatively seldom studied eclipsing binary V865 Cyg (P=0^d.365 days). Its O–C diagram was analysed and new light elements are given. We showed that there is probably no parabolic period increase in V865 Cyg. Instead, a single abrupt period increase can be distinguished in the O–C diagram.     

New times of minimum and a period study for GO Cygni

Times of minimum derived from photometry obtained in 1963, 1967, 1978, and 1979 are presented. With these and previously published times, the period is studied. A constant period increase (quadratic ephemeris) represents most of the times but there was a period decrease in 1934 and possibly in 1984. A 50-year magnetic cycle is discussed On leave from Dyer Observatory, Vanderbilt University, Nashville, Tennessee.