Drift of Polar Prominences in Solar Cycles 13–24

Geomagnetism and Aeronomy - A comparative analysis of the drift velocity of high-latitude prominences to the poles in solar cycles 13–24 is carried out. Data on the positions of prominences...     

Photometric observations of the supernova 2009nr

We present the results of our UBVRI CCD photometry for the second brightest supernova of 2009, SN 2009nr, discovered during a sky survey with the telescopes of the MASTER robotic network. Its light and color curves and bolometric light curves have been constructed. The light-curve parameters and the maximum luminosity have been determined. SN 2009nr is shown to be similar in light-curve shape and maximum luminosity to SN 1991T, which is the prototype of the class of supernovae Ia with an enhanced luminosity. SN 2009nr exploded far from the center of the spiral galaxy UGC 8255 and most likely belongs to its old halo population. We hypothesize that this explosion is a consequence of the merger of white dwarfs.     

The Shape of Sunspots and Solar Activity Cycles

Solar Physics - A new open-source software, called SunMap, has been developed to obtain synoptic maps in an easy and quick way from multiple full-disc solar images. Our objective is to provide a...     

Applying an Automatic Image-Processing Method to Synoptic Observations

We used an automatic image-processing method to detect solar-activity features observed in white light at the Kislovodsk Solar Station. This technique was applied to automatically or semi-automatically detect sunspots and active regions. The results of this automated recognition were verified with statistical data available from other observatories and revealed a high detection accuracy. We also provide parameters of sunspot areas, of the umbra, and of faculae as observed in Solar Cycle 23 as well as the magnetic flux of these active elements, calculated at the Kislovodsk Solar Station, together with white-light images and magnetograms from the Michaelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO/MDI). The ratio of umbral and total sunspot areas during Solar Cycle 23 is ≈?0.19. The area of sunspots of the leading polarity was approximately 2.5 times the area of sunspots of the trailing polarity.     

22-year variations of the solar rotation and solar activity cycles

We have performed a comparative analysis of the results of our study of the 22-year rotation variations obtained from data on large-scale magnetic fields in the Hα line, magnetographic observations, and spectral-corona observations. All these types of data suggest that the rotation rate at low latitudes slows down at an epoch close to the maximum of odd activity cycles. The 22-year waves of rotation-rate deviation from the mean values drift from high latitudes toward the equator in a time comparable to the magnetic-cycle duration. We discuss the possibility of the generation of a solar magnetic cycle by the interaction of 22-year torsional oscillations with the slowly changing or relic magnetic field. We consider the generation mechanisms of the high-latitude magnetic field through a superposition of the magnetic fields produced by the decay and dissipation of bipolar groups and the relic or slowly changing magnetic field and a superposition of the activity wave from the next activity cycle at high latitudes.     

Some notes concerning the prediction of the amplitude of the solar activity cycles

The parameter G, which is determined from the general number of sunspots groups N _g according to the daily observations G=∑(1/N _g )², is offered. This parameter is calculated for the days when there is at least one sunspots group. It characterizes the minimum epoch solar activity. Parameter G mounts to the maximum during the epoch close to the minimal activity of sunspots. According to the data of the sequence of sunspots group in Greenwich–USAF/NOAA observatory format, observation data of Kislovodsk solar station and also daily Wolf number, the changes of parameter G during 100 years were reconstructed. It is demonstrated in the paper that parameter G’s amplitude in minimal solar activity n is linked with the sunspot cycle’s amplitude W _n+1 or one and half cycles. The 24th activity cycle prediction is calculated, which makes W ₂₄=135(±12).     

Polar and Low-Latitude Faculae in Activity Cycles 23–24

Geomagnetism and Aeronomy - Polar and low-latitude faculae were identified in daily images based on white-light observations from the MDI (1996–2011) and SOHO (2010–2019) space...     

V404 CYG/GS 2023+338: Monitoring in the Optical with Robotic Telescopes of the MASTER Global Network during the 2015 Superburst

2070 unique, homogeneous photometric and polarization observations of the microquasar in a binary system with a black hole V404 Cyg/GS2023+338 obtained in 2015 with the MASTER global network of robotic telescopes (16 robotic telescopes located at eight points on the Earth in Russia, Spain, South Africa, and Argentina) are presented. MASTER was the first telescope network to obtain optical observations of the microquasar after its gamma-ray outburst in 2015. Observations were carried out from 18:34:09 UT on June 15, 2015 until December 2015 in four polarizations and in the four standard BV RI filters. The paper presents the results of these observations and a comparative analysis of optical and X-ray data. The observations confirm the previously discovered super-long delays of the optical radiation relative to the X-ray outbursts. Possible mechanisms causing the delay in the optical variations relative to the X-ray variations are discussed. Variability of the optical polarization discovered earlier is confirmed another similar episode reported.

     

Reconstruction of a Hundred Years Series of Solar Filaments from Daily Observational Data

The preliminary results of solar filaments distinguished in daily H-alpha observations at Kodaikanal (1912–2002) are presented. To mark the boundaries of solar filaments, methods based on automated procedures of marking low-contrast objects on the solar disk, as well as editing of the marked boundaries in a semiautomated manner, were developed. The characteristics of solar filaments were analyzed. Latitudinal diagrams of filaments number in 15–23 activity cycles were constructed. As is shown, one maximum in the filament latitudinal distribution may be clearly distinguished during activity cycles in both hemispheres. This maximum is located slightly higher (θ ~ 25°–30°) than the sunspot distribution maximum (θ ~ 14°–17°). However, there are no other local maxima related to the zonal structure of the large-scale magnetic field (Makarov and Sivaraman, 1989).