Search Publications
Evolution of solar active regions: Detecting the emergence of new magnetic field through multifractal segmentation
Golovko, A. A.; Salakhutdinova, I. I.
New emerging magnetic flux is identifed using a multifractal segmentation method used to investigate regularities in the evolution of active regions and activity complexes. The SOLIS, MDI SOHO, and SOT Hinode magnetograms were used. Observations of the active region NOAA 10488 on October 26-28, 2003 indicate considerable variability of areas of ne…
Pulkovo catalog of relative positions and motions of visual double and multiple stars from photographic observations with the 26-inch refractor in 1960-2007
Kiselev, A. A.; Romanenko, L. G.; Kiyaeva, O. V. +7 more
The results of long-term, uniform, photographic observations of visual double and multiple stars obtained on the Pulkovo 26″ refractor are presented. Relative positions are calculated for 259 pairs of visual double stars in 194 systems, with the relative motions also computed for 127 pairs. Lower limits for the total masses of the systems for whic…
Orbits of four visual binaries determined from observations along short arcs
Kiselev, A. A.; Romanenko, L. G.
The orbits of the four visual binaries ADS 246 (GL 15), ADS 7724 ( γ Leo), ADS 10386 (GJ 659), and ADS 14909 (1 Peg) have been determined using the apparent motion parameters (AMP) method. The orbital periods of these stars are 1200, 550, 7500, and 18 000 yr, respectively. The orbits were calculated based on observations along short arcs obtained …
Infrared emission and the destruction of dust in HII regions
Wiebe, D. S.; Kirsanova, M. S.; Pavlyuchenkov, Ya. N.
The generation of infrared (IR) radiation and the observed IR-intensity distribution at wavelengths of 8, 24, and 100 µm in the ionized hydrogen region around a young, massive star is investigated. The evolution of the HII region is treated using a self-consistent chemical-dynamical model in which three dust populations are included—large silicate…
The interplanetary magnetic field: Radial and latitudinal dependences
Khabarova, O. V.
Results of the analysis of spacecraft measurements at 1-5.4 AU are presented within the scope of the large-scale interplanetary magnetic field (IMF) structure investigation. The work is focused on revealing of the radial IMF component ( B r ) variations with heliocentric distance and latitude as seen by Ulysses. It was found out that |…
Rotation of the Hyades derived from Hipparcos data
Vereshchagin, S. V.; Reva, V. G.; Chupina, N. V.
Data from the Hipparcos catalog are used to study the internal kinematics of the Hyades cluster. Cluster members whose proper motions and parallaxes are known with precisions not less than 5 mas/yr and 3 mas were used. The proper motions were reduced to the cluster center. A correlation between a component of the tangential velocity and the parall…
Active regions near the recent solar-cycle minimum: Relation between plasma heating and electrical currents
Livshits, M. A.; Rudenko, G. V.; Grigor'eva, I. Yu. +1 more
Data on small active regions on the Sun collected over three years (2007-2009) are analyzed. Under very quiescent conditions (a low X-ray background level), the shapes of the coronal loops of some active regions correspond fairly well to the shapes of magnetic-field lines calculated in a potential approximation. This is true of several active regi…
Low-energy 3He and 4He ions in interplanetary space during quiet periods of the 23rd solar cycle
Kecskeméty, K.; Logachev, Yu. I.; Surova, G. M. +1 more
Data from the ULEIS instrument aboard the ACE spacecraft are used to study the energy spectra of 3He and 4He ions produced during periods of the quiet Sun in the 23rd solar cycle in the energy range ∼0.08-2 MeV/nucleon. Differences in the spectra and 3He/4He relative abundances for three groups of quiet …
Orbits of the visual binaries ADS 8814 and ADS 8065 from observations along a short arc
Kiselev, A. A.; Romanenko, L. G.; Kiyaeva, O. V. +1 more
The orbits of the visual binaries ADS 8814 and ADS 8065 are determined for the first time. The orbits were calculated using the parameters of the apparent motion, based on position observations along short arcs obtained on the 26-inch refrector of the Pulkovo Observatory, supplemented with radial-velocity observations for the stellar components in…
Dark energy in six nearby galaxy flows: Synthetic phase diagrams and self-similarity
Valtonen, M. J.; Chernin, A. D.; Teerikorpi, P. +4 more
Outward flows of galaxies are observed around groups of galaxies on spatial scales of about 1 Mpc, and around galaxy clusters on scales of 10 Mpc. Using recent data from the Hubble Space Telescope (HST), we have constructed two synthetic velocity-distance phase diagrams: one for four flows on galaxy-group scales and the other for two flows on clus…