Mineralogical and Geochemical Features of a Peat Deposit in the Eutrophic Obskoye Fen under Anthropogenic Load (Western Siberia)

Doklady Earth Sciences - The chemical composition and mineral inclusions in peats and the underlying soils of the eutrophic Obskoye fen (Western Siberia, Tomsk Region) are studied. The basic...     

Multifactorial Method of Search for Small Bodies in Close Orbits

The results of the search for Apollo, Amor, and Aten asteroids with the orbits close to those of meteoroids of the δ-Cancrids meteor complex (code DCA), which consists of the northern (code NCC) and southern (code SCC) branches, are presented. The search for small bodies in close orbits was performed on the basis of a multifactorial method of combining several criteria: Drummond orbital similarity criterion, Kholshevnikov metric, and parameters of the dynamic evolution of the orbits using two catalogs of meteor orbits (Japan Meteor Society, SonatoCo, and CAMS Meteoroid Orbit Database v2.0, CAMS) obtained from television observations. Asteroids in close orbits with the meteoroid orbits of the northern NCC and southern SCC branches of the δ-Cancrids are identified only in the Apollo group. The following asteroids are common for the NCC and SCC branches: 2015 PU228, 2014 YQ34, 2017 YO4 (according to the CAMS orbit catalog); Hephaistos 1978 SB, 2003 RW11, 2006 BF56, 2011 SR12, 2014 RS17, 2001 YB5 (SonatoCo catalog). The asteroid 85182 (1991 AQ) is identified only with the northern NCC branch but in two catalogs of meteor orbits.     

Electric field enhancement in an auroral arc according to the simultaneous radar (EISCAT) and optical (ALIS) observations

The character of a change in the ionospheric electric field when several auroral arcs crossed the region of radar measurements has been analyzed. In one case the plasma conductivity and electric field normal component in an arc increased as compared to their undisturbed values. In another case the field and conductivity changed traditionally (in antiphase). Arcs with an increased field were previously classified as correlating arcs, but their existence was subsequently open to question during optical observations. The usage of the ALIS system of digital cameras made it possible to decrease the errors introduced by optical equipment. The measurements in the vicinity of correlating arcs were performed when these arcs were generated, and a traditional arc was a completed formation. In an originating arc, the field value can depend not only on the ionospheric plasma conductivity but also on the processes in the magnetospheric-ionospheric system resulting in the field enhancement.     

The MASTER Global Robotic Telescope Network: Observations of Asteroid NEA 2015 TB145

The results of white-light photometry for a uniquely long series of data (13.5 hours of observations, 1124 measurements) for the Near-Earth Asteroid (NEA) 2015 TB145 are presented. These data were obtained with the MASTER-Amur and MASTER-Tavrida wide-field robotic telescopes of the Mobile Astronomical System of Telescope-Robots (MASTER) global network of Lomonosov Moscow State University, located in the Crimea and in Blagoveshchensk. The object moved by more than 120° during the observations. The asteroid passed the point of closest approach to the Earth, i.e., observations were carried during both the asteroid's approach and recession. Thus, due to the geometry of the passage, this series of observations contains information about the asteroid viewed at different angles, and is very suitable for precisely determining the shape of the object. Mathematical modeling of the light curve and astrometric positions (with the Asteroids3D code) was carried out, and the probable shape of the asteroid (conical) and the rotation period of 5.9 hours were obtained, as well as the orientation of the rotation axis in ecliptic coordinates: longitude λ = 53°, latitude β = −20°. The derived period coincides with twice the period of 2.9 hours obtained by other observers published earlier, within the uncertainties.

     

A stratigraphic scheme for the division of the Prequaternary deposits of central Crimea

A stratigraphic scheme for dividing the Triassic–Neogene deposits of the central Crimea by suites has been proposed. The division is based on the generalization of our own results and the analysis of the published and unpublished data.