scholarly journals CCD Photometry of the M 67 Cluster in the Vilnius Photometric System

1995 ◽  
Vol 167 ◽  
pp. 363-364
Author(s):  
R. Boyle ◽  
V. Straižys ◽  
F. Vrba ◽  
F. Smriglio ◽  
A. K. Dasgupta
Keyword(s):  
High Sensitivity ◽  
Physical Parameters ◽  
Spectroscopic Methods ◽  
Wide Field ◽  
Photometric System ◽  
Ccd Photometry ◽  
Absolute Magnitudes ◽  
Ccd Detectors

The Vilnius photometric system, consisting of seven passbands at 345, 374, 405, 466, 516, 544 and 656 nm makes it possible to determine spectral classes (or temperatures), absolute magnitudes (or surface gravities), metallicities and peculiarity types for stars of all spectral types in the presence of interstellar reddening (Straizys 1977, 1992a, b). This makes the system very useful for the determination of the physical parameters of stars which are too faint to be studied by spectroscopic methods. The system is especially effective when used with CCD detectors which combine a wide field, high sensitivity and high photometric accuracy.

New calibration of the Vilnius photometric system

2018 ◽  
Vol 14 (A30) ◽  
pp. 486-486
Author(s):  
M. Maskoliunas ◽  
J. Zdanavičius ◽  
V. Čepas ◽  
A. Kazlauskas ◽  
R. P. Boyle ◽  
...  
Keyword(s):  
Photometric Determination ◽  
High Dispersion ◽  
Physical Parameters ◽  
Photometric System ◽  
Homogeneous Sample ◽  
Giant Stars ◽  
Stellar Temperatures ◽  
Absolute Magnitudes ◽  
Gaia Dr2

AbstractThe medium-band Vilnius photometric system with the mean wavelengths at 345 (U), 374 (P), 405 (X), 466 (Y), 516 (Z), 544 (V), and 656 (S) nm for many years was an important tool to determine interstellar reddenings and distances of single stars due to its ability to classify stars of all temperatures in spectral classes and luminosity classes in the presence of different interstellar reddenings. At present, Gaia DR2 presents distances to stars with an unprecedented accuracy at least up to 3 kpc. However, multicolor photometry, which allows the classification of stars as well as the preliminary determination of stellar temperatures, gravities, metallicities and interstellar reddenings, remains an important method for distant stars. Here we present an empirical calibration of the intrinsic color indices of the Vilnius system in terms of physical parameters of stars for dwarf and giant stars of spectral classes F-G-K-M. In any attempted photometric determination of physical parameters of stars it is important to have an extensive and homogeneous sample of spectroscopically determined parameters for stars for which there are also accurate photometric data. As a source catalogue for the Vilnius photometry the latest updated version of the Catalogue of Photoelectric Observations in the Vilnius System was used, which contains compilations from the published photometry for about 11 000 stars. The stars which had both the Gaia DR2 parallaxes and the determinations of stellar parameters from high-dispersion spectra were extracted from this catalogue. The final sample contains more than 1500 stars of spectral classes F-M. The majority of these stars (ca 70%) are not reddened, for others the values of interstellar reddening AV were determined using the regular techniques of photometric classification in the Vilnius system. The absolute magnitudes MV and consequently the luminosity classes were determined using Gaia DR2 parallaxes. We present the analytical expressions for the effective temperature Teff and surface gravity logg and evaluate the errors of solutions for dwarf and giant stars. To test the accuracy of the proposed method, we have compared our results with the stars observed by Gaia and with the stellar parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE and SEGUE. The results of comparison contain 5-6 % outliers.The proposed method allows the fast and straightforward evaluation of stellar physical parameters for the stars observed in the Vilnius photometric system. Despite the fact, that the accuracy of determination is significantly lower than in the case of spectroscopic methods, the method described may be useful for distant faint stars, which are still inaccessible for spectroscopic observations.

scholarly journals New developments in aerosol measurements using stellar photometry

2019 ◽  
Vol 197 ◽  
pp. 02007 ◽  
Author(s):  
Jan Ebr ◽  
Jakub Juryšek ◽  
Michael Prouza ◽  
Jiří Blažek ◽  
Petr Trávníček ◽  
...  
Keyword(s):  
Absolute Calibration ◽  
Wide Field ◽  
Telescope Array ◽  
New Developments ◽  
Fast Determination ◽  
Stellar Photometry ◽  
Southern Site ◽  
Ccd Detectors ◽  
Incoming Light

The idea of using stellar photometry for atmospheric monitoring for optical experiments in highenergy astrophysics is seemingly straightforward, but reaching high precision of the order of 0.01 in the determination of the vertical aerosol optical depth (VAOD) has proven difficult. Wide-field photometry over a large span of altitudes allows a fast determination of VAOD independently of the absolute calibration of the system, while providing this calibration as a useful by-product. Using several years of data taken by the FRAM (F/(Ph)otometric Robotic Atmospheric Monitor) telescope at the Pierre Auger Observatory in Argentina and about a year of data taken by a similar instrument deployed at the planned future Southern site of the Cherenkov Telescope Array in Chile, we have developed methods to improve the precision of this measurement technique towards and possibly beyond the 0.01 mark. Detailed laboratory measurements of the response of the whole system to both the spectrum and intensity of incoming light have proven indispensable in this analysis as the usual assumption of linearity of the CCD detectors is not valid anymore for the conditions of the observations.

scholarly journals Some Physical Parameters and UVBY β Photometry of Trapezium Type Multiple Systems

1995 ◽  
Vol 166 ◽  
pp. 391-391
Author(s):  
G.N. Salukvadze ◽  
G. Sh. Javakhishvili
Keyword(s):  
Photon Counting ◽  
Physical Parameters ◽  
Photometric System ◽  
Early Type ◽  
Multiple Systems ◽  
Early Type Stars ◽  
Absolute Magnitudes ◽  
Bolometric Correction ◽  
Semi Empirical ◽  
Mirror Telescope

The presented paper deals with the results of electrophotometric observations of 59 components of 19 trapezia in Strömgren and Crawford six-colour photometric system. The multiple systems, selected from the Abastumani Catalogue of Trapezia (Salukvadze, 1978), are: ABAO 2, 8, 34, 48, 51, 62, 75, 94, 245, 312, 313, 316, 324, 348, 356, 363, 387, 396.Observations were made on the 125-cm mirror telescope with the use of a one-channel photometer, based on photon counting, with diaphragms 10″ and 20″. Reduction was done on the Observatory computer with a procedure described by Salukvadze and Javakhishvili (1989).We calculated the indices [m1],[c1] and [u-b] as in (Strömgren 1967, Philip and Egret 1980). The unreddened indices (b-y), m1 and c1 were calculated by the formulae of Crawford (1975).Semi-empirical calibrations for effective temperature, bolometric correction and mass for early-type stars, using Strömgren photometric indices c0 and beta, are given by Balona (1984). In order to determine absolute magnitudes we used the calibration from Balona and Shobbrook (1984).

scholarly journals Applications of the UB1B2V1G Photometric System

1973 ◽  
Vol 50 ◽  
pp. 145-151
Author(s):  
M. Golay
Keyword(s):  
Absolute Magnitude ◽  
Interstellar Extinction ◽  
Stellar Atmospheres ◽  
Physical Parameters ◽  
Photometric System ◽  
Peculiar Stars ◽  
Valid Comparison ◽  
Effects Of Rotation ◽  
First Time

This photometric system which was described for the first time in 1963 by Golay has been in use at the Geneva Observatory since 1959. We are involved in a long term observational programme having as objective the study of cluster stars, peculiar stars and interstellar extinction. This research aims at the determination of physical parameters such as effective temperature, gravity, abundance, or those of spectral type, absolute magnitude, [Fe/H]. To permit such an analysis the photometric effects of rotation, of multiplicity and of interstellar extinction were given particular attention. Attempting to attain the above mentioned purposes, we have had to give great care to the precision of the measurements during their acquisition as also during their reduction. Finally, in view of allowing a valid comparison between observations and the theory of stellar atmospheres, particular care had to be given to the maintenance of the pass-bands and to the knowledge of their form.We intend here to give the main bibliographical references relative to the articles which present the general properties of the system, its applications and the catalogues.

scholarly journals Photometric Classification of Carbon-Rich Stars

1989 ◽  
Vol 106 ◽  
pp. 62-62
Author(s):  
V. Straizys
Keyword(s):  
Photometric Determination ◽  
Abundance Ratio ◽  
Photometric System ◽  
The Mean ◽  
Absolute Magnitudes

The Vilnius seven-color photometric system with the mean wavelengths of bandpasses at 345, 374, 405, 466, 516, 544, and 656 nm is intended for photometric determination of spectral classes, absolute magnitudes, and metallicities of stars and the amount of interstellar reddening. At the same time, different reddening-free diagrams of the system make it possible to recognize stars with different peculiarities. Carbon-rich stars are among these types of objects. For separation of carbon, barium, and CH stars from normal stars, the diagram Q (345, 374, 466, 544), Q (405, 516, 656) is the best. Its merit is based on sensitivity of the 405 magnitude to the violet depression and of the 374 magnitude to the absorption of the C3, SiC, and CN bands, This diagram can be used to estimate the C/0 abundance ratio with corresponding calibration at hand.

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

Population Change, Modernization and Welfare. By Joseph Spengler. Prentice-Hall Inc., Englewood Cliffs, N.J. 1974.

1977 ◽  
Vol 16 (2) ◽  
pp. 220-222
Author(s):  
Zeba A. Sathar
Keyword(s):  
Population Growth ◽  
Population Change ◽  
Population Control ◽  
Stable Condition ◽  
Developed Countries ◽  
Wide Field ◽  
Wide Scale ◽  
Socio Economic Variables ◽  
Almost All

The book covers a wide field, touching on almost all aspects of popula¬tion change on a world-wide scale. It discusses, using world and country data, the relationships between demographic and socio-economic variables, and elaborates on" their relative importance in the determination of population problems which confront the world as a whole and nations individually. Policies designed to alleviate these problems are discussed with an emphasis on those related to population control. The first chapter is entitled "Population Growth: Past and Prospective" and reviews the various parameters associated with population change in the past and in the future. It touches upon the concept of a stable population in order to show the elements which cause a population to change (i.e. remove it from its stable condition). The main elements of change, population growth, migration, mortality and natality are discussed individually. The chapter is concluded by a description of the main differences in these elements and other socio-economic conditions as they exist in the less-developed and developed countries.

Determination of Selected Phthalates in Some Commercial Cosmetic Products by HPLC-UV

2020 ◽  
Vol 23 (10) ◽  
pp. 1010-1022
Author(s):  
Emrah Dural
Keyword(s):  
High Performance ◽  
Phthalate Esters ◽  
High Sensitivity ◽  
Hplc Method ◽  
Cosmetic Products ◽  
Limit Of Quantification ◽  
Nail Polish ◽  
Accuracy And Precision ◽  
Butyl Phthalate

Aim and scope: Due to the serious toxicological risks and their widespread use, quantitative determination of phthalates in cosmetic products have importance for public health. The aim of this study was to develop a validated simple, rapid and reliable high-performance liquid chromatography (HPLC) method for the determination of phthalates which are; dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), di(2- ethylhexyl) phthalate (DEHP), in cosmetic products and to investigate these phthalate (PHT) levels in 48 cosmetic products marketing in Sivas, Turkey. Materials and Methods: Separation was achieved by a reverse-phase ACE-5 C18 column (4.6 x 250 mm, 5.0 μm). As the mobile phase, 5 mM KH2PO4 and acetonitrile were used gradiently at 1.5 ml min-1. All PHT esters were detected at 230 nm and the run time was taking 21 minutes. Results: This method showed the high sensitivity value the limit of quantification (LOQ) values for which are below 0.64 μg mL-1 of all phthalates. Method linearity was ≥0.999 (r2). Accuracy and precision values of all phthalates were calculated between (-6.5) and 6.6 (RE%) and ≤6.2 (RSD%), respectively. Average recovery was between 94.8% and 99.6%. Forty-eight samples used for both babies and adults were successfully analyzed by the developed method. Results have shown that, DMP (340.7 μg mL-1 ±323.7), DEP (1852.1 μg mL-1 ± 2192.0), and DBP (691.3 μg mL-1 ± 1378.5) were used highly in nail polish, fragrance and cream products, respectively. Conclusion: Phthalate esters, which are mostly detected in the content of fragrance, cream and nail polish products and our research in general, are DEP (1852.1 μg mL-1 ± 2192.0), DBP (691.3 μg mL-1 ± 1378.5) and DMP (340.7 μg mL-1 ±323.7), respectively. Phthalates were found in the content of all 48 cosmetic products examined, and the most detected phthalates in general average were DEP (581.7 μg mL-1 + 1405.2) with a rate of 79.2%. The unexpectedly high phthalate content in the examined cosmetic products revealed a great risk of these products on human health. The developed method is a simple, sensitive, reliable and economical alternative for the determination of phthalates in the content of cosmetic products, it can be used to identify phthalate esters in different products after some modifications.

The protonation of the ethylenediphosphinetetraacetate anion and the crystal structure of the bis (hydrogen bromide) of ethylenediphosphinetetraacetic acid

1981 ◽  
Vol 46 (12) ◽  
pp. 3063-3073 ◽  
Author(s):  
Jana Podlahová ◽  
Bohumil Kratochvíl ◽  
Vratislav Langer ◽  
Josef Šilha ◽  
Jaroslav Podlaha
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Determination ◽  
Free Acid ◽  
Hydrogen Bromide ◽  
Carboxyl Groups ◽  
Spectroscopic Methods ◽  
X Ray ◽  
Partial Formation

The equilibria and mechanism of addition of protons to the ethylenediphosphinetetraacetate anion (L4-) were studied in solution by the UV, IR, 1H and 31P NMR spectroscopic methods. A total of six protons can be bonded to the anion. They are added stepwise, first with partial formation of zwitterions containing P-H bonds, which then dissociate with formation of the free acid, H4L, where all four protons are bonded in carboxyl groups. The formation of zwitterions is strongly dependent on the concentration. In the final stage, the acid bonds two additional protons to form the bis-phosphonium cation, H6L2+. A number of isostructural salts containing this cation, H4L.2 HX (X = Cl, Br, I), have been prepared. The X-ray crystal structure determination of the bromide confirmed the expected arrangement. The bromide crystals are monoclinic, a = 578.2, b = 1 425.0, c = 1 046.7 pm, β = 103.07° with a space group of P21/c, Z = 2. The final R factor was 0.059 based on 1 109 observed reflections. The structure consists of H6L2+ cations containing protons bonded to phosphorus atoms (P-H distance 134 pm) and of bromide anions, located in gaps which are also sufficiently large for I- anions in the isostructural iodide. The interbonding of phosphonium cations proceeds through hydrogen bonds, C-OH...O=C, in which the O...O distance is 275.3 pm.

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