Long-term predictive assessments of solar and geomagnetic activities made on the basis of the close similarity between the solar inertial motions in the intervals 1840–1905 and 1980–2045

The solar inertial motions (orbits) (SIMs) in the years 1840–1905 and 1980–2045 are of a disordered type and they are nearly identical. This fact was used for assessing predictive capabilities for the sizes of three future sunspot cycles and for the time variation of the geomagnetic aa-index up to 2045. The author found that the variations in sunspot numbers in the interval 1840–1867 and in the interval 1980–2007 are similar, especially after 1850 (1990). The differences may be ascribed to the lower quality of the sunspot data before 1850. A similarity between the variations in geomagnetic aa-index in the intervals 1844–1867 and 1984–2007 is also found. Moreover, the aa-index in these intervals have the same best fit lines (the polynomials of the fourth order) with close positions of the extrema. The extrema of the best fit line for the aa-index in the interval 1906–1928 which corresponds to the first half of the ordered, trefoil interval of the SIM have the opposite positions to them. The correlation coefficient between the aa-indices in the interval 1844–1866 and in the interval 1984–2006 is 0.61. In contrast, the correlation coefficient between the aa-indices in the interval 1844–1866 and in the interval 1906–1928 is ?0.43. Cautious predictions have been made: the author believes that the cycles 24–26 will be a repeat of cycles 11–13, i.e. they could have heights around 140 (100), 65 and 85, they will have lengths of 11.7, 10.7 and 12.1 years. The maxima of the cycles should occur in 2010, 2023 and 2033, the minima in 2007, 2018, 2029 and 2041. Up to 2045, the aa-index could repeat its values for the interval 1868–1905. The results indicate that solar and geomagnetic activities are non random processes. If these predictions may come true, then further evidence of the primary role of the SIM in solar variability is established.     

Variations in the Brightness and Polarization of μ CEP

Observations of the brightness and polarization of CEP over 1983-2002 are presented. An almost sinusoidal curve with a slightly varying amplitude and a period of about 850 days was fit to the light curve. The minima in the actual light curve often appear to be flooded with additional radiation compared to the smoothed curve. As an explanation of this phenomenon, we propose a working hypothesis whereby some radiation that is reflected back into the atmosphere near the equator through veiling by titanium oxide then partially diffuses into the near-polar regions where it escapes.     

The G–O Rule and Waldmeier Effect in the Variations of the Numbers of Large and Small Sunspot Groups

We have analyzed the combined Greenwich and Solar Optical Observing Network (SOON) sunspot group data during the period of 1874??C?2011 and determined variations in the annual numbers (counts) of the small (maximum area A _M<100 millionth of solar hemisphere, msh), large (100??A _M<300?msh), and big (A _M??300?msh) spot groups. We found that the amplitude of an even-numbered cycle of the number of large groups is smaller than that of its immediately following odd-numbered cycle. This is consistent with the well known Gnevyshev and Ohl rule (G?CO rule) of solar cycles, generally described by using the Zurich sunspot number (R _Z). During cycles 12??C?21 the G?CO rule holds good for the variation in the number of small groups also, but it is violated by cycle pair (22, 23) as in the case of R _Z. This behavior of the variations in the small groups is largely responsible for the anomalous behavior of R _Z in cycle pair (22, 23). It is also found that the amplitude of an odd-numbered cycle of the number of small groups is larger than that of its immediately following even-numbered cycle. This might be called the ??reverse G?CO rule??. In the case of the number of the big groups, both cycle pairs (12, 13) and (22, 23) violated the G?CO rule. In many cycles the positions of the peaks of the small, large, and big groups are different, and considerably differ with respect to the corresponding positions of the R _Z peaks. In the case of cycle?23, the corresponding cycles of the small and large groups are largely symmetric/less asymmetric (the Waldmeier effect is weak/absent) with their maxima taking place two years later than that of R _Z. The corresponding cycle of the big groups is more asymmetric (strong Waldmeier effect) with its maximum epoch taking place at the same time as that of R _Z.     

Ammonia in Jupiter’s Atmosphere: Spatial and Temporal Variations of the NH<Subscript>3</Subscript> Absorption Bands at 645 and 787 Nm

Based on the material of long-term spectrophotometric observations of Jupiter, we studied the weak absorption bands of ammonia at 645 and 878 nm, whose behavior had previously been little studied. A clearly expressed depression of ammonia absorption in the 787-nm band was found in the Northern Equatorial Belt (NEB) of Jupiter. In the Great Red Spot, this band also exhibits substantial weakening. The position of the depression in the NEB is similar to that of the enhanced brightness temperature detected in the observations of the millimeter-wave radio emission, which is considered to be a result of the reduced ammonia content in this belt. At the same time, the weakening of the 787-nm band in the Red Spot is most likely caused by the enhanced bulk density of clouds, which influences the formation of absorption bands in the multiple scattering by cloud particles. The brightness temperature in the Red Spot is relatively low, as seen from observations in the radio and thermal IR ranges. We studied the spatial and temporal variations of the 645- and 787-nm bands in five belts of Jupiter: the Equatorial Zone (EZ), both Equatorial Belts (SEB and NEB), and both Tropical Zones (STZ and NTZ). The observations covered the time interval from 2005 to 2015, i.e., almost a complete orbital period of Jupiter. These observations confirmed the systematic character of the depression of the 787-nm band in the NEB and the difference in the latitudinal variations of the 645- and 787-nm bands. The latter can be related to features of the vertical distribution of the cloud density, which has a different influence on bands of different intensity.     

Spatial Structures of the North–South Asymmetry in the Green Coronal Line and Magnetic Fields

Astronomy Letters - The spatial distribution of the north–south (N–S) asymmetry over 1977–2001 is studied. A comparison of the distributions and time variations of the asymmetry...     

Variations of Polarization in the Emission of ℴ Andromedae and LZ Cephei

The results of observations of polarization for the Be star And that are given are in fully satisfactory agreement with the results obtained by Arsenijevic, Vince, and Kubicela in 1974-1977. All these observations together support Harmanec's hypothesis that strengthening of the circumstellar envelope of And occurs during periastron passage of its companion, moving in an elongated orbit with a period of 8.5 years. The results of polarimetric observations of LZ Cep indicate that its slight, variable intrinsic polarization may originate, as in most semidetached systems, in the scattering of radiation of these stars from particles of matter escaping from the component that is filling its Roche lobe.     

On the Flux-Rope Topology of Ejecta Observed in the Period 1997 – 2006

In the following study our aim is to analyse the magnetic flux-rope topology of some events observed in the interplanetary medium related to ejecta. The magnetic field structures associated with interplanetary coronal mass ejections are globally classified in magnetic clouds and ejecta. One of the main questions regarding these phenomena concerns their flux-rope or non-flux-rope magnetic field line configuration. From the experimental measurements the only way to elucidate such a question is analysing the corresponding data by means of a flux-rope physical model. After selecting the ejecta events observed during the period 1997?–?2006, we have analysed them in light of an analytical model with that topology for the magnetic field components, initially developed for magnetic clouds, and with a non-force-free character; then, incorporating the expansion of the magnetic structure during their evolution in the interplanetary medium. Different parameters obtained from the fitting of the model are related to the orientation of the axis of the magnetic flux-rope structure and, additionally, the closest distance approach of the spacecraft to its axis. One of the main conclusions achieved concerns the fact that the axes of most of those structures are close to the Sun–Earth line, which implies that the passage of the spacecraft through the corresponding ejecta event is by its flank. In general, we show a rough procedure for the analysis and classification of ejecta in terms of their magnetic field topology.     

Comparison of the Characteristics of Magnetic Clouds and Magnetic Cloud-Like Structures for the Events of 1995 – 2003

Using nine years of solar wind plasma and magnetic field data from the Wind mission, we investigated the characteristics of both magnetic clouds (MCs) and magnetic cloud-like structures (MCLs) during 1995 – 2003. A MCL structure is an event that is identified by an automatic scheme (Lepping, Wu, and Berdichevsky, Ann. Geophys. 23, 2687, 2005) with the same criteria as for a MC, but it is not usually identifiable as a flux rope by using the MC (Burlaga et al., J. Geophys. Res. 86, 6673, 1981) fitting model developed by Lepping, Jones, and Burlaga (Geophys. Res. Lett. 95(11), 957, 1990). The average occurrence rate is 9.5 for MCs and 13.6 for MCLs per year for the overall period of interest, and there were 82 MCs and 122 MCLs identified during this period. The characteristics of MCs and MCL structures are as follows: (1) The average duration, Δt, of MCs is 21.1 h, which is 40% longer than that for MCLs (Δt=15 h); (2) the average (minimum B _z found in MC/MCL measured in geocentric solar ecliptic coordinates) is −10.2 nT for MCs and −6 nT for MCLs; (3) the average Dst_min (minimum Dst caused by MCs/MCLs) is −82 nT for MCs and −37 nT for MCLs; (4) the average solar wind velocity is 453 km s⁻¹ for MCs and 413 km s⁻¹ for MCLs; (5) the average thermal speed is 24.6 km s⁻¹ for MCs and 27.7 km s⁻¹ for MCLs; (6) the average magnetic field intensity is 12.7 nT for MCs and 9.8 nT for MCLs; (7) the average solar wind density is 9.4 cm⁻³ for MCs and 6.3 cm⁻³ for MCLs; and (8) a MC is one of the most important interplanetary structures capable of causing severe geomagnetic storms. The longer duration, more intense magnetic field and higher solar wind speed of MCs, compared to those properties of the MCLs, are very likely the major reasons for MCs generally causing more severe geomagnetic storms than MCLs. But the fact that a MC is an important interplanetary structure with respect to geomagnetic storms is not new (e.g., Zhang and Burlaga, J. Geophys. Res. 93, 2511, 1988; Bothmer, ESA SP-535, 419, 2003).     

Temporal Pointing Variations of the Solar Dynamics Observatory’s HMI and AIA Instruments on Subweekly Time Scales

Achieving subarcsecond co-registration across varying time-lines of multi-wavelength and instrument images is difficult and requires an accurate characterization of the instrument pointing jitter. We investigated the internal pointing errors on daily and yearly time-scales that occur across the Solar Dynamics Observatory’s (SDO) Atmospheric Imaging Assembly (AIA) and Helioseismic Magnetic Imager (HMI). Using cross-correlation techniques on the AIA 1700 Å passband and the HMI line-of-sight magnetograms from three years of observational image pairs at approximately three-day intervals, internal pointing errors were quantified. Pointing variations of ±?0.26″ (jitter-limited) and ±?0.50″ in the solar East–West (x) and North–South (y) directions, respectively, were measured. AIA observations of the Venus transit in June 2012 were used to measure existing coalignment offsets in all passbands. We found that the AIA passband pointing variations are 〈ΔX _CO〉=1.10″±1.41″ and 〈ΔY _CO〉=1.25″±1.24″ when aligned to the HMI nominal image center, referred to here as the CutOut technique. Minimal long-term pointing variations found between limb and correlation derived pointings provide evidence that the image-center positions provided by the instrument teams achieve single-pixel accuracy on time scales shorter than their characterization. However, daily AIA passband pointing variations of ??1.18″ indicate that autonomous subarcsecond co-registration is not fully achieved yet.     

The Relation between the Amplitude and the Period of Solar Cycles

The maximum amplitudes of solar activity cycles are found to be well anti-correlated (r = -0.72) with the newly defined solar cycle lengths three cycles before (at lag -3) in 13-month running mean sunspot numbers during the past 190 years. This result could be used for predicting the maximum sunspot numbers. The amplitudes of Cycles 24 and 25 are estimated to be 149.5±27.6 and 144.3±27.6, respectively.     

Spectrophotometry of Jupiter in the Wavelength Range 320–1100 nm: Long-Term Observations of Variations over the Disk

Based on long-term spectrophotometric observations of Jupiter in the wavelength range 320–1100 nm, we investigate the variations of aerosol extinction (at 320–600 nm) and methane–ammonia absorption (at 600–1100 nm) over Jupiter's disk. We give estimates of the optical parameters for the upper cloud layer of the planet, the overlying stratospheric haze, and a Rayleigh atmosphere.     

Influence of the Gravitational Fields of the Moon and the Sun on Long-Period Variations in the Proper Rotation of “Midas” Satellites

We report the results of an analysis of the variation of the proper rotation of several destabilized satellites over many-year long time intervals. The cause of the cyclic variations of the proper rotation period of “Midas-7” satellite, which has been orbiting the Earth since 1963 at an altitude of 3700 km, have long been unclear. These variations could not be explained either by the influence of the terrestrial atmosphere and terrestrial magnetic field, or by solar activity. Based on the results of 40-year long observations of “Midas-4,” “Midas-6,”, and “Midas-7” satellites it was established that their proper rotation exhibits not only dissipative braking variations, but also long-period variations with the periods of 477 days (“Midas-4”), 466 days (“Midas-6”), and 346 days (“Midas-7”) with different amplitudes. These variations in the case of the above satellites have well-defined resonance nature. An explanation of the processes found is proposed based on the results of this study and simulations of the observed orbital dynamics of the satellites. Long-period variations of the proper spacecraft rotation arise as a result of the combined effect of the gravitational fields of the Earth, Moon, and Sun depending on the orientation of their orbital planes in space. The amplitudes of such variations is determined by the inclination of satellite orbits to the equator: the closer it is to the pole (i.e., to 90?), the stronger the effect.     

The Long-term Behavior of the North – South Asymmetry of Sunspot Activity

A new index, the cumulative difference of sunspot activity in the northern and southern hemispheres, respectively, is proposed to describe the long-term behavior of the North – South asymmetry of sunspot activity and to show the balance (or bias) of sunspot activity in the two solar hemispheres on a long-term scale. Sunspot groups and sunspot areas from June 1874 to January 2007 are used to show the advantage of the index. The index clearly shows a long-term characteristic time scale of about 12 cycles in the North – South asymmetry of sunspot activity. Sunspot activity is found to dominate in the southern hemisphere in cycle 23, and in cycle 24 it is predicted to dominate still in the southern hemisphere. A comparison of the new index with other similar indexes is also given.     

Variations of the harmonic components of the X-ray pulse profile of PSR B1509–58

We used the Fourier decomposition technique to investigate the stability of the X-ray pulse profile of a young pulsar PSR B1509–58 by studying the relative amplitudes and phase differences of its harmonic components with respect to the fundamental using data from the Rossi X-Ray Timing Explorer. Like most young rotation powered pulsars, PSR B1509–58 has a high spin down rate. It also has less timing noise, allowing accurate measurement of higher order frequency derivatives which in turn helps in the study of the physics of pulsar spin down. Detailed investigation of pulse profiles over the years will help us establish any possible connection between the timing characteristics and the high energy emission characteristics for this pulsar.Furthermore, the study of pulse profiles of short period X-ray pulsars can also be useful when used as a means of interplanetary navigation. The X-ray pulse profile of this source has been analyzed for 15 yr(1996–2011). The long term average amplitudes of the first, second and third harmonics(and their standard deviation for individual measurements) compared to the fundamental are 36.9%(1.7%), 13.4%(1.9%) and 9.4%(1.8%) respectively. Similarly, the phases of the three harmonics(and standard deviations) with respect to the fundamental are 0.36(0.06), 1.5(0.2) and 2.5(0.3) radian respectively. We do not find any significant variation of the harmonic components of the pulse profile in comparison to the fundamental.     

Secular Perion Changes and Fundamental Parameters of Long–Period Cepheids

Hydrodynamic computations of nonlinear Cepheid pulsation models with periods from 20 to 100 day on the evolutionary stage of core helium burning were carried out. Equations of radiation hydrodynamics and time–dependent convection were solved with initial conditions obtained from selected models of evolutionary sequences of population I stars with initial masses from 8 M_⊙ to 12.5 M_⊙. For each crossing of the instability strip the pulsation period Π and the rate of period change \(\dot \prod \) were derived as a function of evolutionary time. Comparing results of our computations with observational estimates of Π and \(\dot \prod \) we determined fundamental parameters (the age, the mass, the luminosity and the radius) of seven long–period Cepheids. Theoretical estimates of the stellar radius are shown to agree with radius measurements by the Baade–Wesselink technique within 3% for RS Pup and GY Sge whereas for SV Vul the disagreement between theory and observations does not exceed 10%.     

Comparative analysis of long-period variations in day duration and solar activity from 1700–2003

A comparative analysis of both long-period deviations in the duration of a day from the standard (86400 s) and solar activity during the years 1700–2003 has been conducted. The comparative analysis was based on the average annual data on LOD (http://hpiers.obspm.fr/eop-pc/) and the number of sunspots W (http://www.wdcb.ru/stp/). The analysis was aimed at studying the evolution of the solar-terrestrial relationship under conditions of insufficient physical data on the origin and interaction of such oscillations in irregular variations in the duration of a day and in parameters characterizing solar activity. The analysis was conducted using three methods, i.e., the periodogram method, the method of exponential data approximation (the Prony method), and the technique of wavelet data transformation. A comparison of the analysis results allows the general conclusion to be drawn that such variations over ～11-yr-long and ～22-yr-long periods are coherent in the data on LOD and W. The amplitude of a squared absolute value of coherence comprises 72% for 11-year and 74% for 22-year variations.     

A Simple Method to Check the Reliability of Annual Sunspot Number in the Historical Period 1610 – 1847

A simple method to detect inconsistencies in low annual sunspot numbers based on the relationship between these values and the annual number of active days is described. The analysis allowed for the detection of problems in the annual sunspot number series clustered in a few explicit periods, namely: i) before Maunder minimum, ii) the year 1652 during the Maunder minimum, iii) the year 1741 in Solar Cycle −1, and iv) the so-called “lost” solar cycle in the 1790s and the subsequent onset of the Dalton Minimum.