Subchloride synthesis in titanium metallurgy

Zakirov, R. A.; Parfenov, O. G.; Пашков, Г. Л.

doi:10.1134/s001250080904003x

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…It is evident that the eclipse depth varies by O m . 12 year after year. Accordingly, a conclusion can be drawn that the eclipse depth varies from period to period, from month to month and year after year.…”

Section: Conclutionsmentioning

confidence: 99%

Study of nonstationary processes in the close binary system RY Scuti

2009

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We present results of reanalysis of old electrophotometric data of early type close binary system RY Scuti obtained at the Abastumani Astrophysical Observatory, Georgia, during 1972Georgia, during -1990 years and at the Maidanak Observatory, Uzbekistan, during 1979-1991 years. It is revealed non-stable processes in RY Sct from period to period, from month to month and from year to year. This variation consists from the hundredths up to the tenths of a magnitude. Furthermore, periodical changes in the system's light are displayed near the first maximum on timescales of a few years. That is of great interest with regard to some similar variations seen in luminous blue variable (LBV) stars. This also could be closely related to the question of why RY Sct ejected its nebula.Keywords: Close binaries, early-type stars, individual RY Scuti.1. Introduction. RY Scuti is a unique massive binary star system in a rare transitional evolutionary phase. It is surrounded by a young circumstellar nebula. The system is thought to be a rare progenitor of a WR+OB system, so it may be a "Rosetta Stone" for understanding the late evolutionary stages of close binary stars -particularly the formation of close WR binaries by tidally-induced mass transfer and mass loss. So, the close binary RY Sct undergoes mass-transfer and mass exchange processes and has complicated structure in its outer atmospheric layers. It possibly suffers evolutionary changes in a comparatively short time interval that is significant for constructing an evolutionary model of the system.The short history of investigation of this binary system is as follows: Merrill 1 found the He II 4686 line in the spectrum of RY Sct being specific only to nebulae and their nuclei. There are strong forbidden lines of [Fe III] and [Si III] in the spectrum, as well as emission lines of hydrogen, helium and other elements. RY Sct was observed as a radio source 2. The presence of the intense emission lines and radio emission (as in  Lyr) favored the assumption that there may be a small H II region around RY Sct 3 . The star is strongly reddened by the surrounding gas and dust shell 4. Based on spectroscopic observations, Cowley and Hutchings 5 found that the binary system consists of two early-type supergiants with a mass ratio of q=M 2 /M 1 =1.25. Guirichin and Mardirossian 6 suggested that the secondary must be surrounded by a geometrically thick accretion disk, which can explain its anomalously low luminosity, and that RY Sct is similar to the peculiar  Lyr system and is currently on its way to become a Wolf-Rayet (WR) system. Milano et al.

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Section: Conclutionsmentioning

confidence: 99%

Study of nonstationary processes in the close binary system RY Scuti

2009

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“…This has substantially changed our conception of this system. The results of coordinated studies were published in the Bulletin of Abastumani Astrophysical Observatory No.58 (Kumsiashvili, a), b); Skul'skij; Babaev; Karetnikov; Cherepashchuk;Zakirov; under the editorship of Kumsiashvili. The results of complex investigation were presented by Kumsiashvili in 1988 at IAU International Conference "Algols" in Canada (Kumsiashvili, 1989).…”

Section: Introductionmentioning

confidence: 99%