UZ Librae is the giant primary of a close binary system with extremely fast rotation and revolution. Its distinctive characteristics include an optical light curve with a large amplitude and a high X-ray luminosity. UZ Librae was observed twice at five months interval in August 2000 and January 2001 by the XMM-Newton space observatory. Serie of lines of highly ionized Fe and several lines of the Ly and He series are visible in the reflection grating spectra, most notably from C, O and Ne. The corresponding ions are associated with plasma components with temperature in the range 3-8MK. Bremstrahlung emission from plasma at high temperature (T>3x107K) indicates an intense flaring activity on UZ Librae. This is also supported by a Ne abundance enhancement relative to oxygen reminiscent of abundance anomalies observed during stellar and solar flares. In contrast to oxygen and neon, the abundance of Fe in the corona of UZ Librae is determined to be a tenth of the solar photospheric value. We conjecture that the large fluid kinetic helicity induced by the rapid rotation of the star currently generates magnetic fields with two characteristic scales comparable with compact loops within solar active regions and with larger cooler loops interconnecting solar active regions. The X-ray emission of UZ Librae would be strongly enhanced not only due to the occurrence of these magnetic structures, but mainly due to their large surface coverage and to their permanent interactions responsible for heating UZ Librae plasma to high temperatures. A rotational modulation effect could have contributed to the luminosity variation between the two XMM-Newton observations since a large fraction of the X-ray emitting material might be located above large photospheric spots detected on Doppler images of the star.
(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases
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
(redshift may be not displayed if the data value is <0 and the database inside value is a radial velocity)
[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 (119 between 1850 and 2024) (Total 119)
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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