Properties of dwarf stars in Cygnus OB2

We present the results of investigation of five stars, originally classified as dwarfs, belonging to Cyg OB2 association, their stellar and wind properties. Using both TLUSTY and CMFGEN codes we derived effective temperatures, surface gravities, chemical abundances, mass-loss rates and projected rotation velocities. Due to the fact that distance to the stars is well known, we were able to estimate their luminosities. Using evolutionary models we estimated the ages of these sample stars and find that lower mass ones - MT282 and MT343 - belong to older population of the association. Their ages are greater than 10 Myr. The ages of three other stars - MT317, MT299, MT259 - are between 4-6 Myr.Comment: 16 pages, 10 figures, accepted for publication in PAS

ESPriF: the Echelle Spectropolarimeter of the BTA Primary Focus. Correction of Low-Frequency Variations in the Star Image

The development of a corrector for low-frequency variations in the star image at the input of ESPriF, the echelle spectropolarimeter of the BTA primary focus, is reported. New technical solutions have made it possible to extend the operating frequency range to 10Hz for stars brighter than 13^m.Comment: 9 pages, 2 figure

Препаративный синтез пролиллейцилпролина

Using trifluoracetyl and tert-butoxycarbonyl protection for amine groups, preparative methods for synthesis of prolylleucylproline have been developed.С использованием трифторацетильной и трет-бутоксикарбонильной аминозащитных групп предложены препаративные методы синтеза пролиллейцилпролина. Физико-химические характеристики полученных образцов трипептида практически совпадают, что может свидетельствовать об отсутствии процессов рацемизации на всех стадиях синтеза пролиллейцилпролина с применением трифторацетильной защитной группы

RESEARCHES OF LONG-TERM VARIATIONS IN URANUS AND NEPTUNE SPECTRA

The results of long-term spectral observations of Solar System giant planets Uranus and Neptune are presented here. Data were obtaining in period 2002-2012 at the peak Terskol Observatory (Northern Caucasus, Russia) using 2-meter Ritchey-Chretien telescope Zeiss-2000 with help coude echelle spectrograph and at the Special astrophysical observatory (SAO RAS, Northern Caucasus, Russia) with help 6-meter telescope using echelle spectrograph NES. Raman light scattering of solar photons by hydrogen molecules in the atmosphere spectra of Uranus and Neptune was registered in most powerful Fraunhofer lines H&K CaII as the "emission" details in center cores of these lines. Relative values of Raman scattering contribution for noted lines are estimated. Also, we have carried out long-term monitoring of Raman light scattering variations in cloudy surface spectra