Catalog of stars with high proper motions (version 3.0)

We compiled a catalog (containing astrometric and astrophysical characteristics) of 4 302 200 stars with high proper motions (no less than 40 mas/year) using original measurements of proper motions of stars from the catalogs FONAK 1.1, HIPPARCOS, ??Tycho-2,?? UCAC2,3, CMC (STAR 11), PPM, PPMX, NPM1, NPM2, XZ80Q, Pul-3, Pul2, NLTT, GCVS, LHS, ??Lowell Proper Motion,?? and ??Bruce Proper Motion,?? as well as some data from approximately 800 other published sources. The location of our catalog is ftp://ftp.mao.kiev.ua/pub/astro/h-pms3.dat.     

Valleys,paleolakes and possible shorelines at the Libya Montes/Isidis boundary: Implications for the hydrologic evolution of Mars

We describe the results of our morphologic, stratigraphic and mineralogic investigations of fluvial landforms, paleolakes and possible shoreline morphologies at the Libya Montes/Isidis Planitia boundary. The landforms are indicative of aqueous activity and standing bodies of water, including lakes, seas and oceans, that are attributed to a complex hydrologic cycle that may have once existed on Mars in the Noachian (>3.7 Ga) and perhaps also in the Hesperian (>3.1 Ga). Our observations of the Libya Montes/Isidis Planitia boundary between 85°/86.5°E and 1.8°/5°N suggest, that (1) the termination of valley networks between roughly ?2500 and ?2800 m coincide with lake-size ponding in basins within the Libya Montes, (2) an alluvial fan and a possible delta, layered morphologies and associated Al-phyllosilicates identified within bright, polygonally fractured material at the front of the delta deposits are interpreted to be the results of fluvial activity and discharge into a paleolake, (3) the Arabia “shoreline” appears as a series of possible coastal cliffs at about ?3600 and ?3700 m indicating two distinct still stands and wave-cut action of a paleosea that temporarily filled the Isidis basin the Early Hesperian, and (4) the Deuteronilus “shoreline” appears at ?3800 m and is interpreted to be a result of the proposed sublimation residue of a frozen sea that might have filled the Isidis basin, similar to the Vastitas Borealis Formation (VBF) identified in the northern lowlands. We interpret the morphologic–geologic setting and associated mineral assemblages of the Libya Montes/Isidis Planitia boundary as results of fluvial activity, lake-size standing bodies of water and an environmental change over time toward decreasing water availability and a cold and dry climate.     

Observations of extrasolar planet transits with the automated telescopes of the Pulkovo Astronomical Observatory

Exoplanet observations have been performed on the automated Pulkovo Observatory telescopes. We have obtained 33 transit light curves for 16 known exoplanets and six transit observations for three exoplanet candidates discovered by the Kepler telescope. Based on our observations, we have reliably confirmed the existence of an exoplanet with an extremely large radius, R _pl = 1.83 ± 0.16R _Jup, in the system KOI 256 and detected a strong deviation of its orbital revolution from the theoretically predicted one. During the transit of the exoplanet WASP-12b across the stellar disk, we detected bursts that could be caused by the planet transit across spots on the star or by the presence of a satellite around this exoplanet. We detected possible periodic variations in the duration of the exoplanet transit across the stellar disk with time for HAT-P-12b that could be caused by variations in orbital inclination. The transit duration and depth, the central transit time, and the radius and orbital inclination of the planet have been estimated. The equilibrium temperature and albedo have been estimated for several exoplanets.     

Cross-identifications of stars with high proper motions (Version 2.0)

A cross index list of 493 200 stars with proper motions higher than 0.04″/yr (ftp://ftp.mao.kiev.ua/pub/astro/c-ihpms2) was compiled on the basis of the original determinations for the FONAK1.1 catalog stars, the data from the Hipparcos, Tycho-2, UCAC2, CMC (STAR 11), PPM, NPM1, NPM2, XZ80Q, Pul-3, PUL2, GCVS, NLTT, LHS, Lowell Proper Motion, and Bruce Proper Motion catalogs, as well as the data published in other sources.     

Nonresonant effects and hydrogen transition line shape in cosmological recombination problems

Data on the fluctuations in cosmic microwave background (CMB) radiation, whose accuracy is expected to increase in the immediate future, allow the cosmological recombination of atomic hydrogen and its interaction with the CMB radiation to be studied. Nonresonant effects play an important role in these recombination processes. We consider the quantum-mechanical foundations of the nonresonant processes and present our calculations for the differential two-photon decay rates of the 3s and 3d levels in the hydrogen atom. This article was submitted by the authors in English.     

The First Results of Tephrochronological Study of Late Pleistocene–Holocene Volcanic Eruptions in the Zhom–Bolok River Valley (Eastern Sayan)

Doklady Earth Sciences - The first results of tephrochronological studies of Late Pleistocene–Holocene volcanic eruptions in the Zhom-Bolok River valley (Eastern Sayan) are reported. Based on...     

An Unusually Powerful Water-Maser Flare in the Galactic Source W49N

The most powerful flare ever registered in the Galactic water-maser source W49N has been detected in long-term monitoring data in the 6₁₆–5₂₃ transition with line frequency f = 22.235 GHz carried out on the 22-m Simeiz, 32-m Toruń, 100-m Effelsberg, and 32-m Medicina radio telescopes, beginning in September 2017 and continuing in 2018. Some stages of the flare were monitored daily. Detailed variations of the source spectral flux density with time have been obtained. At the flare maximum, the flux exceeded P ≈ 8 × 10⁴ Jy, and this was record highest flux registered over the entire history of observations of this source. Important conclusions related to details of the mechanism for the H₂O line emission have been drawn. An exponential increase in the flare flux density was detected during both the rise and decline of the flare. The data obtained indicate that the maser is unsaturated, and remained in this state up to the maximum observed flux densities. Additional support for the idea that the maser is unsaturated is the shape of the dependence of the line width on the flux. The characteristics of the variations of the spectral flux density are probably associated with a sharp increase in the density of the medium and the photon flux that led to an increase in the temperature from an initial level of 10–40 K to hundreds of Kelvins. Interferometric maps of the object during the increase in the spectral flux density of the flare have been obtained. A possible mechanism for the primary energy release in W49N is considered.