scholarly journals OAO-2 Observations of Beta Lyrae and a Provisional Interpretation

1971 ◽  
Vol 15 ◽  
pp. 308-313 ◽  
Author(s):  
Yoji Kondo ◽  
George E. McCluskey ◽  
Ted E. Houck
Keyword(s):  
Photometric Data ◽  
Light Curves ◽  
Spectroscopic Information ◽  
Orbital Revolution ◽  
Short And Long Term ◽  
Photoelectric Observations ◽  
Long Term Variations

AbstractSix-color ultraviolet photoelectric observations of Beta Lyrae obtained with OAO-2 are presented. These observations, made at 1380 Ǡ, 1500 Ǡ, 1920 Ǡ, 2460 Ǡ, 2980 Ǡ, and 3330 Ǡ, represent the first truly continual coverage of the light changes of Beta Lyrae during one orbital revolution and were obtained in November 1970. The photometric data are supplemented by spectral scans in the wavelength intervals 3800 Ǡ to 1800 Ǡ and 2000 Ǡ to 1050 Ǡ; the latter interval was scanned at 10 Ǡ resolution once during every OAO-2 orbit, i. e., about 100 minutes. Anomalous features, such as asymmetries and short and long term variations, are present in the light curves. A tentative discussion of solutions of the light curves is given. The problems of combining the photometric and spectroscopic information to arrive at a model of the system are also discussed.

scholarly journals Long-Term Variations of the Compact Radio Source Sgr A∗ at the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 535-541 ◽  
Author(s):  
Jun-Hui Zhao ◽  
R. D. Ekers ◽  
W. M. Goss ◽  
K. Y. Lo ◽  
Ramesh Narayan
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
High Velocity ◽  
Galactic Center ◽  
Light Curves ◽  
Radio Flux ◽  
Compact Radio Source ◽  
Sgr A ◽  
Long Term Variations

We investigate the long-term flux density variations of the compact radio source Sgr A∗ at the galactic center by combining recent VLA observations with previous Green Bank interferometer data. We present radio flux density light-curves for Sgr A∗ at 20, 11, 6 and 3.7 cm from 1974 to 1987. Long-term variability with a timescale of at least 5 years is seen at 20 cm and there is evidence for more rapid variations at the shorter wavelengths. The variability timescales at 20, 11 and 6 cm fit the λ2 scaling predicted by the theory of refractive scintillation suggesting that the variability could be due to this cause. However, the timescales are relatively short, implying an unusually high velocity in the scattering screen. The modulation index of the variability is large and relatively independent of wavelength.

scholarly journals Short‐ and Long‐Term Variations in the Reykjanes Geothermal Reservoir From Seismic Noise Interferometry

2019 ◽  
Vol 46 (11) ◽  
pp. 5788-5798 ◽  
Author(s):  
Pilar Sánchez‐Pastor ◽  
Anne Obermann ◽  
Martin Schimmel ◽  
Cornelis Weemstra ◽  
Arie Verdel ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Geothermal Reservoir ◽  
Noise Interferometry ◽  
Short And Long Term ◽  
Long Term Variations

scholarly journals The Later Evolution of the Contact Binaries AP Leo, AK Her, AB And and AM Leo

2002 ◽  
Vol 187 ◽  
pp. 331-336
Author(s):  
L. Li ◽  
Z. Han ◽  
F. Zhang
Keyword(s):  
Light Curve ◽  
Rapid Change ◽  
Cataclysmic Variables ◽  
Light Curves ◽  
Common Envelope ◽  
Physical Mechanisms ◽  
Contact Binaries ◽  
The Common ◽  
Long Term Variations

AbstractA detailed study of the periods and light curves of binaries AK Her, AP Leo, AB And and AM Leo is presented. Based on the study of the O – C curves, we find that the period variation of each system contains several components with different frequencies, and we suggest that the periodical variations in the periods are likely influenced by different mechanisms. Based on the study of the light curve changes, we find that the light curves exhibit two kinds of variations: rapid variations and long-term variations. We investigate the physical mechanisms which may underlie the variations of the period and the light curve of each system and obtain some new conclusions. According to the characteristics of the rapid light variation in these systems, we suggest that the rapid change in the light curve is probably caused by pulsation of the common envelope, and that the mechanism(s) causing the pulsation may be mass transfer through the inner Lagrangian point L1 or its variation. Finally, the evolutionary trends of these systems are discussed, and we suggest that these systems may be progenitors of cataclysmic variables.

scholarly journals Short- and long-term variations in non-linear dynamics of heart rate variability

1996 ◽  
Vol 31 (3) ◽  
pp. 400-409 ◽  
Author(s):  
J. K. Kanters ◽  
M. V. Hojgaard ◽  
E. Agner ◽  
N.-H. Holstein-Rathlou
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Linear Dynamics ◽  
Non Linear ◽  
Short And Long Term ◽  
Long Term Variations

scholarly journals Elimination of long-term variations from chaotic light curves

2013 ◽  
Vol 334 (9) ◽  
pp. 984-987
Author(s):  
E. Plachy ◽  
Z. Kolláth
Keyword(s):  
Light Curves ◽  
Long Term Variations
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