2001A&A...367..840D -
Astronomy and Astrophysics, volume 367, 840-847 (2001/3-1)
A photometric study of the W UMa-type system U Pegasi.
DJURASEVIC G., ROVITHIS-LIVANIOU H., ROVITHIS P., ERKAPIC S. and MILOVANOVIC N.
Abstract (from CDS):
In the present study, the activity of the eclipsing binary of the W UMa-type system U Peg is examined by analysing the photoelectric observations covering the period from 1950 to 1989. During this period, the light curves show significant differences and asymmetries. The analysis of the corresponding light curves is made using Djurasevic's inverse problem method. To explain the light-curve asymmetries and variations, we used a Roche model that involved regions containing spots on the components. The analysis shows that the system U Peg is in an overcontact configuration (fover∼14.9%). The Roche model with spotted areas on the cooler component yields a good fit of the observations for the whole set of the analysed light curves without any changes of the basic system parameters. This indicates that the complex nature of the light-curve variations during the examined period can be explained by the evolution and motion of spotted areas on the cooler component. According to the obtained results, the spotted areas cover a significant part of the stellar surface; the changes in their location and size with time are examined.
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Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of radial velocity (or/and redshift) is : "value [error] (wavelength) quality bibcode"
value : radial velocity or/and redshift (Heliocentric frame) according to your Output Options
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[error] : error of the corresponding value displayed before
(wavelength) : wavelength range of the measurement : Rad, mm, IR, Opt, UV, Xray, Gam or '∼'(unknown)
quality : flag of quality ( A=best quality -> E=worst quality, ∼=unknown quality)
References (247 between 1850 and 2024) (Total 247)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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