Long period variations of the geomagnetic field and their spatial distribution in Europe

1977 ◽  
Vol 21 (2) ◽  
pp. 148-158 ◽  
Author(s):  
Jana Pěčová ◽  
Oldřich Praus ◽  
Karel Pěč ◽  
A Janáčková
Keyword(s):  
Spatial Distribution ◽  
Geomagnetic Field ◽  
Long Period ◽  
Period Variations ◽  
Distribution In Europe

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

On the Long-Period Variations in the F2Region of the Ionosphere

1938 ◽  
Vol 26 (11) ◽  
pp. 1340-1346 ◽  
Author(s):  
Keikitiro Tani ◽  
Y. Ito ◽  
H. Sinkawa
Keyword(s):  
Long Period ◽  
Period Variations

Long-period variations in the magnetic field of small-scale solar structures

2016 ◽  
Vol 56 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
P. V. Strekalova ◽  
Yu. A. Nagovitsyn ◽  
A. Riehokainen ◽  
V. V. Smirnova
Keyword(s):  
Magnetic Field ◽  
Small Scale ◽  
Long Period ◽  
Period Variations ◽  
The Magnetic Field

Slow variability and circumstellar shells of red variable stars

1987 ◽  
Vol 122 ◽  
pp. 541-542
Author(s):  
T. Lloyd Evans
Keyword(s):  
Variable Stars ◽  
Circumstellar Dust ◽  
Infrared Photometry ◽  
Constant Ratio ◽  
Giant Stars ◽  
Long Period ◽  
Period Variations ◽  
Cyclic Variations ◽  
Circumstellar Shells ◽  
The Mean

Infrared photometry shows that while all RV Tauri stars have circumstellar dust shells, the RVb stars with slow cyclic variations in mean light as well as the 30–100 day variations common to all RV stars have more hot dust close to the star (Lloyd Evans 1985). Many M giant stars which are variables of semiregular type also show long-period variations in the mean light (O'Connell 1933; Payne-Gaposchkin 1954), with a roughly constant ratio between the two periods. Payne-Gaposchkin (1954) found P2/P1 ~9.4 for red variables of type M and P2/P1 ~19.4 for stars of type F-K, most of which are FV Tauri stars. Re-analysis using the more extensive data available now indicates P2/P1 ~10 for the M giants and P2/P1 ~15 for the FV Tauri stars. The nature of the long-period variability is unknown (Wood 1975).

Solar Radiation at 1200 MC/S., 600 MC/S., and 200 MC/S

1949 ◽  
Vol 2 (1) ◽  
pp. 48 ◽  
Author(s):  
FJ Lehany ◽  
DE Yabsley
Keyword(s):  
Magnetic Field ◽  
Body Temperature ◽  
Solar Radiation ◽  
Thermal Emission ◽  
Black Body ◽  
Sunspot Area ◽  
The Sun ◽  
Long Period ◽  
Period Variations ◽  
The Magnetic Field

Daily observations of solar radiation at frequencies of 1200 Mc/s., 600 Mc/s., and 200 Mc/s. taken between August 18 and November 30, 1947, are described. The characteristics of the radiation at 200 Mc/s. were in general agreement with those observed by earlier workers. At 600 Mc/s. and 1200 Mc/s., the received intensity was normally steady on any one day but underwent long-period variations over a range of about two to one. The radiation received when the sun was almost free of sunspots corresponded to an effective black-body temperature of 0.5 million �K. at 600 Mc/s. and 0.1 million �K. at 1200 Mc/s. As sunspots appeared, the temperature rose and showed marked oar- relation with sunspot area. It is considered that radiation at these frequencies is entirely thermal in origin and that the long-period variations are at least partly due to the influence of the magnetic field of sunspots on the mechanism of thermal emission from a magneto-ionic medium. On a few occasions, isolated disturbances were observed on 600 Mc/s. and 1200 Mc/s. some of which were associated with chromospheric flares and radio fade-outs. The difficulties arising in the calibration of the apparatus and the steps taken to overcome them are discussed in detail.

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