Calibration of the Strömvil Photometric System

2003 ◽  
Vol 12 (4) ◽  
Author(s):  
A. Kazlauskas ◽  
V. Straižys ◽  
R. P. Boyle ◽  
A. G. Davis Philip ◽  
V. Laugalys ◽  
...  
Keyword(s):  
Physical Parameters ◽  
Photometric System ◽  
Photoelectric Photometry ◽  
Color Indices ◽  
Effective Temperatures

AbstractA calibration of color indices of the Strömvil photometric system in terms of physical parameters of stars is presented. The calibration is based on photoelectric photometry of about 1000 stars with known effective temperatures, distances, gravities and metallicities. The observations were accomplished in 2000-2003 with the 1.5 meter telescope of the Steward Observatory. The distances were taken from the Hipparcos catalog, and T

scholarly journals Energy Distribution, Photometry and Physical Characteristics of the Sun and Solar Analogs

1986 ◽  
Vol 7 ◽  
pp. 853-861
Author(s):  
I. N. Glushneva ◽  
E. A. Markova ◽  
A. V. Kharitonov
Keyword(s):  
Solar Energy ◽  
Energy Distribution ◽  
Physical Characteristics ◽  
Photometric Data ◽  
Physical Parameters ◽  
Photometric System ◽  
The Sun ◽  
Color Indices ◽  
Effective Temperatures ◽  
Solar Analogs

AbstractColor indices of solar analogs in the Vilnius seven-color photometric system are discussed. The physical parameters (effective temperatures, radii and luminosities) for solar analogs with reliable spectrophotometric and photometric data were obtained by means of infrared fluxes. The effective temperatures of 16 Cyg A and B, which are considered to be the closest solar analogs are 5854 and 5664 K, respectively. The radii of both stars are in the range of 1 Ro < R < 1.4 Ro and luminosities 1.2Lo < L < 2.1 Lo for 16 Cyg A and Lo < L < 1.7 Lo for 16 Cyg B depending on different evaluations of the distances. We find that the relative solar energy distribution in the 0.33 – 1.25 μm range determined by Neckel and Labs (1984) is reliable enough, however the absolute fluxes are slightly too low at the maximum of energy distribution.

scholarly journals Concerning the Temperatures of Central Stars of Planetary Nebulae

1983 ◽  
Vol 103 ◽  
pp. 534-535
Author(s):  
L. Kohoutek ◽  
W. Martin
Keyword(s):  
Effective Temperature ◽  
Planetary Nebulae ◽  
Photoelectric Photometry ◽  
Effective Temperatures ◽  
Central Stars

Recently Pottasch (1981, Astron. Astrophys. 94, L13) published extremely high effective temperatures of some central stars of planetary nebulae (> 200 000 K). Our study of planetary nebulae based on photoelectric photometry does not confirm his results. A histogram of Tz(HI) and Tz(HeII) shows smooth distribution of Tz with the maximum of about 48 000°K (HI) and 90 000°K (HeII), respectively; the effective temperature of none of the 62 planetary nuclei exceeds 120 000°K.

On the Measurement of Atmospheric Extinction by Rufener’s Method

1979 ◽  
Vol 3 (5) ◽  
pp. 326-327
Author(s):  
Z. KviZ
Keyword(s):  
Adverse Effect ◽  
Photometric System ◽  
Photoelectric Photometry ◽  
Atmospheric Extinction ◽  
Air Mass

The coefficient of atmospheric extinction may change during the night and in fact it often does. This has an adverse effect on the determination of atmospheric extinction by simple Bouguer plot of magnitude against air mass. This effect was studied by Rufener (1964), who introduced for the purpose of accurate photoelectric photometry in the Geneva photometric system the method of two ‘extinction stars’. His method consists of the measurement of two stars of the same colour — one starting at high air mass 2 - 3, the M-star (for French montante = rising) and the second starting simultaneously in the meridian at low air mass, the D—star (for descending).

scholarly journals Physical parameters for the EXPORT sample. Rotational velocities and effective temperatures

2004 ◽  
Vol 202 ◽  
pp. 127-129
Author(s):  
E. Solano ◽  
B. Montesinos ◽  
A. Mora ◽  
Keyword(s):  
Chemical Analysis ◽  
Physical Parameters ◽  
Planetary Formation ◽  
La Palma ◽  
Effective Temperatures ◽  
Detailed Chemical

The methods used to calculate projected rotational velocities and effective temperatures for the targets observed during the 1998-1999 La Palma International Time campaign are described here. This is part of a project whose main goal is to perform a detailed chemical analysis of these objects and to study their potential implications in the planetary formation phenomenon.

scholarly journals Accurate Spectroscopic Surface Gravities for 8 Sub-Giants

1988 ◽  
Vol 132 ◽  
pp. 387-388
Author(s):  
Bengt Edvardsson
Keyword(s):  
Error Analysis ◽  
Single Line ◽  
Strong Line ◽  
Photometric System ◽  
Atmospheric Parameters ◽  
Chemical Abundances ◽  
Effective Temperatures ◽  
Ionization Equilibria ◽  
Excitation Equilibrium

Logarithmic surface gravities between 2.9 and 3.8 (cgs) have been determined for eight G8IV-K2III stars from the analysis of pressure broadened wings of strong metal lines. Comparisons with trigonometrically determined surface gravities give support to the spectroscopic results. A thorough and rather conservative error analysis suggests that the errors are smaller than about 30% and confirms that the method is very insensitive to uncertainties in the fundamental stellar atmospheric parameters. Surface gravities of α Cen A and B and of Arcturus have also been obtained. Chemical abundances have been derived for 12 elements from Na to Ni, and for five heavier elements from Y to Nd have tentative abundances been derived from a single line of each element. Effective temperatures in the photometric system of Frisk (1983) are found to be consistent with spectroscopic temperatures from the excitation equilibrium of Fe I. Surface gravities determined from the ionization equilibria of Fe and Si are found to be systematically lower than the strong line gravities, which may be an effect of errors in the model atmospheres, or departures from LTE in the ionization equilibria.

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

1995 ◽  
Vol 164 ◽  
pp. 378-378
Author(s):  
G.N. Salukvadze ◽  
G.Sh. Javakhishvili
Keyword(s):  
Physical Parameters ◽  
Photometric System ◽  
Multiple Systems ◽  
Trapezium Type

The present paper deals with the results of electrophotometric observations of 59 components of 19 trapezia in the Stroemgren and Crawford six-colour photometric system.

scholarly journals How Normal are the Peculiar a Stars

1993 ◽  
Vol 138 ◽  
pp. 126-130 ◽  
Author(s):  
G.S.D. Babu ◽  
B.S. Shylaja
Keyword(s):  
Mass Range ◽  
Physical Parameters ◽  
Effective Temperatures ◽  
Ap Stars

AbstractA comparison of various physical parameters of the normal A stars with those obtained by using the peculiarity-free zones of Ap stars indicate that the peculiar A stars may be treated as normal stars as far as their effective temperatures, radii, bolometric corrections and the mass range are concerned.

scholarly journals The Absolute Luminosity of RR Lyrae Variables

1988 ◽  
Vol 126 ◽  
pp. 587-588
Author(s):  
C. Cacciari ◽  
G. Clementini ◽  
L. Prevot
Keyword(s):  
Surface Brightness ◽  
Radial Velocities ◽  
Photoelectric Photometry ◽  
Rr Lyrae ◽  
Metal Abundance ◽  
Metal Abundances ◽  
Complete Set ◽  
Effective Temperatures ◽  
Absolute Magnitudes ◽  
Absolute Luminosity

We have taken UBVRI photoelectric photometry and CORAVEL radial velocities for 6 field RR Lyraes, i.e. SW And, YZ Cap, SW Dra, SS For, RV Phe and V440 Sgr, with the purpose of applying the Baade-Wesselink (B-W) method and determining their absolute magnitudes. The present improvements with respect to previous applications of the method are: a) the use of the (V-I) color, which shows the smallest sensitivity to gravity and metal abundance in the color-visual surface brightness plane. b) the use of a new grid of model atmospheres by Buser and Kurucz (1986), which include an improved treatment of opacity and convection. They provide a complete set of models for the relevant values of effective temperatures, gravities and metal abundances, thus avoiding the need of inaccurate interpolations or extrapolations.

scholarly journals Revised Empirical Formulae for the Absolute Magnitudes and Intrinsic Colors of RRab Stars

2000 ◽  
Vol 176 ◽  
pp. 268-268 ◽  
Author(s):  
A. R. Walker ◽  
G. Kovács
Keyword(s):  
Light Curve ◽  
Absolute Magnitude ◽  
Large Datasets ◽  
Light Curves ◽  
Linear Functions ◽  
Physical Parameters ◽  
Fourier Amplitude ◽  
Color Indices ◽  
The Absolute ◽  
Absolute Magnitudes

AbstractThe relations between the physical parameters of the RRab stars and the Fourier parameters of their light curves have been reanalyzed on the basis of new CCD data. We show that the absolute magnitude MV and the dereddened color indices (B − V)0, (V − I)0 are linear functions of the period and of the A1 Fourier amplitude of the V light curve. Due to the large datasets, we are able to test the consistency of the formulae on independent sets. The present results are in good or fair agreement with our previous studies, despite the fewer number of significant parameters entering in the revised formulae.

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