Melanterite and szomolnokite as weathering products of pyrite from the Bazhenovo Formation

Weathering of pyrite in the core recovered from black shales of the Bazhenovo Formation (Upper Jurassic-Lower Cretaceous) in the West Siberian marine basin promoted the successive formation of melanterite (FeSO₄ · 7H₂O) and szomolnokite (FeSO₄ · H₂O). Szomolnokite was detected in West Siberia for the first time.     

Dependence of the types of coasts and coastal eolian relief on the variations of the sea level using the example of the Caspian Sea

In this work, the history of the development of the Turali area (the Dagestan coast of the Caspian Sea) in the Late Holocene is under consideration. The analysis of the geological structure of the bay bar that separates the Bolshoy Turali lagoon from the sea, the granulometric analysis of the coastal deposits, and the data of geo-radar profiles make it possible to assert that the large eolian relief forms were formed during the New Caspian (Novokaspiyskoe) transgression of the Caspian Sea.     

Error analysis of integrated water vapor measured by СIMEL photometer

Water vapor plays a key role in weather and climate forming, which leads to the need for continuous monitoring of its content in different parts of the Earth. Intercomparison and validation of different methods for integrated water vapor (IWV) measurements are essential for determining the real accuracies of these methods. CIMEL photometers measure IWV at hundreds of ground-based stations of the AERONET network. We analyze simultaneous IWV measurements performed by a CIMEL photometer, an RPG-HATPRO MW radiometer, and a FTIR Bruker 125-HR spectrometer at the Peterhof station of St. Petersburg State University. We show that the CIMEL photometer calibrated by the manufacturer significantly underestimates the IWV obtained by other devices. We may conclude from this intercomparison that it is necessary to perform an additional calibration of the CIMEL photometer, as well as a possible correction of the interpretation technique for CIMEL measurements at the Peterhof site.     

Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68R_Earth) and Kepler-10b (∼1.416R_Earth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects.     

Determining Both Tropospheric and Stratospheric СО2 Contents Using a Ground-Based IR Spectroscopic Method

Izvestiya, Atmospheric and Oceanic Physics - Results obtained from ground-based high spectral resolution measurements of solar IR radiation absorption spectra are analyzed. These measurements have...     

On Geoseismic Noise and Helioseismic Oscillations

Izvestiya, Physics of the Solid Earth - Abstract—In their paper published in Izvestiya, Physics of the Solid Earth, G.A. Sobolev et al. (2020) discussed the results of their study. Firstly,...     

Solar limb darkening in the wings of the CaII H and K lines

The method for measuring solar limb darkening has been proposed, and the formulas, describing the law of solar limb darkening in the wings of the CaII H (396.849 nm) and K (393.369 nm) lines, have been derived. To operate at arbitrary points on the Sun’s surface, it is necessary to know the law of solar limb darkening, which is specific in different spectral regions. The procedure of spectrum correction for a flat field, proposed in our previous works, is based on comparing line-free spectral regions with the solar center reference spectrum from the atlas by Brault and Neckel [1994].