Models of infrared spectra of Sakurai's Object (V4334 Sgr) in 1997

Theoretical spectral energy distributions computed for a grid of hydrogen-deficient and carbon-rich model atmospheres have been compared with the observed infrared (1--2.5 $\mu$m) spectra of V4334 Sgr (Sakurai's Object) on 1997 April 21 and July 13. The comparison yields an effective temperature of \Tef = 5500 $\pm$ 200 K for the April date and \Tef = 5250 $\pm$ 200 K for July. The observed spectra are well fitted by Asplund et al. (1999) abundances, except that the carbon abundance is higher by 0.3 dex. Hot dust produces significant excess continuum at the long wavelength ends of the 1997 spectra. \keywords{Stars: individual: V4334 Sgr (Sakurai's Object) -- Stars: AGB and post-AGB evolution -- Stars: model atmospheres -- Stars: energy distributions -- Stars: effective temperatures}Comment: 6 pages, 7 eps figs, accepted for A

Сутність зеленого маркетингу

В останні роки глобальне середовище погіршилося через поступове зростання населення. Знищення екологічних систем пов'язане зі способом життя та поведінкою споживачів, а саме з надмірним споживанням та нераціональним використанням ресурсів. До найважливіших глобальних екологічних проблем можна віднести зміни клімату, утрату біорізноманіття, забруднення атмосфери, утилізацію відходів. Сьогоднішній стан навколишнього середовища та катастрофічні наслідки життєдіяльності людства вимагають перегляду існуючих підходів до господарювання. Новий підхід має базуватись на глибокій повазі до довкілля, раціональному використанні ресурсів та переробці відходів виробництва і споживання. Однією з таких концепцій є зелений маркетинг. У статті дістало подальшого розвитку визначення екологічного маркетингу, що на відміну від існуючих, акцентує увагу на належності екологічного маркетингу до соціально-етичного маркетингу та узгодженні економічних та екологічних інтересів споживача, виробника та суспільства, шляхом формування та задоволення попиту на екологічну (екофрендлі, нешкідливу для довкілля) продукцію. Обґрунтовано відмінності зеленого маркетингу та традиційного. Основними відмінностями зеленого маркетингу є фокусування на довгострокових наслідках; першочергове зосередження на проблемах довкілля; маркетингове супровдження всього ланцюжка вартості товару від видобутку сировини до споживання і утилізації; застосування проактивної стратегії поводження з відходами. Виявлено основні переваги та проблеми використання зеленого маркетингу на підприємстві. Розширено поняття «зеленого» комплексу маркетингу шляхом додавання ще двох елементів: «Люди» та «Процеси». Зелений маркетинг заохочує покращення екологічної обізнаності клієнтів та надання їм можливості брати участь у природоохоронній діяльності, допомагає раціоналізувати використання обмежених ресурсів. Зелений маркетинг сприяє виробництву та розповсюдженню екологічно чистих товарів та послуг, що максимально задовольняє потреби споживачів найбільш екологічно чистим способом. Це сприяє зменшенню виснаження та експлуатації природних ресурсів.In recent years the global environment has deteriorated due to gradual growth of the population. The destruction of environmental systems is linked to the lifestyle and behavior of consumers, especially with excessive consumption and inappropriate use of resources. Climate change, loss of biodiversity, atmospheric pollution, and waste management are the most important global environmental issues. Today's state of the environment and the catastrophic consequences of human activities require revision of existing approaches to management. The new approach should be based on deep respect for the environment, rational use of resources and the recycling of waste from production and consumption. Green marketing addresses these challenges. The article further developed the definition of environmental marketing, which, unlike existing ones, emphasizes the importance of environmental marketing to social and ethical marketing and the harmonization of the economic and environmental interests of the consumer, producer and society by creating and satisfying the demand for environmental (eco-friendly, non-hazardous for environment) products. The difference between green marketing and traditional one is substantiated. The main difference in green marketing is focusing on its long-term effects; it gives priority focus on environmental issues; marketing support of the entire value chain of goods from extraction of raw materials to consumption and utilization; the use of a proactive waste management strategy. The main advantages and problems of using green marketing in the enterprise are discussed. The concept of a "green" marketing mix is expanded by adding two more elements: "People" and "Processes". Green marketing encourages customer training to improve their environmental awareness and enable them to participate in environmental activities, and helps to rationalize using of scarce resources. Green marketing contributes to the production and distribution of environmentally friendly goods and services that maximally meet the needs and desires of people in the most beneficial and environmentally friendly way. This contributes to reducing the depletion and exploitation of natural resources

Astronomy in Ukraine

The current and prospective status of astronomical research in Ukraine is discussed. A brief history of astronomical research in Ukraine is presented and the system organizing scientific activity is described, including astronomy education, institutions and staff, awarding higher degrees/titles, government involvement, budgetary investments and international cooperation. Individuals contributing significantly to the field of astronomy and their accomplishments are mentioned. Major astronomical facilities, their capabilities, and their instrumentation are described. In terms of the number of institutions and personnel engaged in astronomy, and of past accomplishments, Ukraine ranks among major nations of Europe. Current difficulties associated with political, economic and technological changes are addressed and goals for future research activities presented.Comment: Paper to be published in ``Organizations and Strategies in Astronomy'' -- Vol. 7, Ed. A. Heck, 2006, Springer, Dordrecht; 25 pages, 2 figs, 2 table

Formation of a tourism brand of Rostov region for foreign tourists

The authors of the article focus both on aspects of Linguocultural training of professionals to work with foreign tourists and on the problem of the choice of the tourism brand of Rostov Region, its historical stages, as well as the issue of the lack of a systematic approach to its formatio

Modeling the spectrum of V4334 Sgr (Sakurai's Object)

Theoretical spectral energy distributions were computed for a grid of hydrogen-deficient and carbon-rich model atmospheres of T(eff) in the range of 5000-6250 K and log g = 1.0 - 0.0 by the technique of opacity sampling, taking into account continuous, molecular band and atomic line absorption. These energy distributions were compared with the spectrum of V4334 Sgr (Sakurai's object) of April, 1997 in the wavelength interval 300-1000 nm. We show that (1) the shape of the theoretical spectra depends strongly on T(eff) but only very weakly on the hydrogen abundance; (2) the comparison of the observed and computed spectra permits to estimate T(eff) approximately 5500 K for V4334 Sgr in April, 1997, and its interstellar reddening (plus a possible circumstellar contribution) E(B-V) approximately 0.70.Comment: 7 pages, 8 figures, LaTeX, accepted by Astronomy and Astrophysic

Boron in Very Metal-Poor Stars

We have observed the B I 2497 A line to derive the boron abundances of two very metal-poor stars selected to help in tracing the origin and evolution of this element in the early Galaxy: BD +23 3130 and HD 84937. The observations were conducted using the Goddard High Resolution Spectrograph on board the Hubble Space Telescope. A very detailed abundance analysis via spectral synthesis has been carried out for these two stars, as well as for two other metal-poor objects with published spectra, using both Kurucz and OSMARCS model photospheres, and taking into account consistently the NLTE effects on the line formation. We have also re-assessed all published boron abundances of old disk and halo unevolved stars. Our analysis shows that the combination of high effective temperature (Teff > 6000 K, for which boron is mainly ionized) and low metallicity ([Fe/H]<-1) makes it difficult to obtain accurate estimates of boron abundances from the B I 2497 A line. This is the case of HD 84937 and three other published objects (including two stars with [Fe/H] ~ -3), for which only upper limits can be established. BD +23 3130, with [Fe/H] ~ -2.9 and logN(B)_NLTE=0.05+/-0.30, appears then as the most metal-poor star for which a firm measurement of the boron abundance presently exists. The evolution of the boron abundance with metallicity that emerges from the seven remaining stars with Teff < 6000 K and [Fe/H]<-1, for which beryllium abundances were derived using the same stellar parameters, shows a linear increase with a slope ~ 1. Furthermore, the B/Be ratio found is constant at a value ~ 20 for stars in the range -3<[Fe/H]<-1. These results point to spallation reactions of ambient protons and alpha particles with energetic particles enriched in CNO as the origin of boron and beryllium in halo stars.Comment: 38 pages, 11 Encapsulated Postscript figures (included), uses aaspp4.sty. Accepted for publication in The Astrophysical Journal. The preprint is also available at: http://www.iac.es/publicaciones/preprints.htm

Modelling the spectral energy distribution of the red giant in RS Ophiuchi: Evidence for irradiation

We present an analysis of optical and infrared spectra of the recurrent nova RS Oph obtained during between 2006 and 2009. The best fit to the optical spectrum for 2006 September 28 gives Teff = 3900 K for log g = 2.0, while for log g = 0.0 we find Teff = 4700 K, and a comparison with template stellar spectra provides Teff ~ 4500 K. The observed spectral energy distribution (SED), and the intensities of the emission lines, vary on short (≲1 d) time-scales, due to disc variability. We invoke a simple one-component model for the accretion disc, and a model with a hot boundary layer, with high (~3.9 × 10-6M⊙ yr-1) and low (~2 × 10-8M⊙ yr-1) accretion rates, respectively. Fits to the accretion disc-extracted infrared spectrum (2008 July 15) yield effective temperatures for the red giant of Teff = 3800 ± 100 K (log g = 2.0) and Teff = 3700 ± 100 K (log g = 0.0). Furthermore, using a more sophisticated approach, we reproduced the optical and infrared SEDs of the red giant in the RS Oph system with a twocomponent model atmosphere, in which 90 per cent of the surface has Teff = 3600 K and 10 per cent has Teff = 5000 K. Such structure could be due to irradiation of the red giant by the white dwarf. © 2015 The Authors

Optical studies of the X-ray transient XTE J2123-058 -I. Photometry

We present optical photometry of the X-ray transient XTE J2123-058, obtained in July-October 1998. The light curves are strongly modulated on the 5.95hrs orbital period, and exhibit dramatic changes in amplitude and form during the decline. We used synthetic models which include the effect of partial eclipses and X-ray heating effects, to estimate the system parameters, and we constrain the binary inclination to be i=73+-4 degrees. The model is successful in reproducing the light curves at different stages of the decay by requiring the accretion disc to become smaller and thinner by 30% as the system fades by 1.7 mags in the optical. From Aug 26 the system reaches quiescence with a mean magnitude of R=21.7+-0.1 and our data are consistent with the optical variability being dominated by the companion's ellipsoidal modulation.Comment: 6 pages, 6 figure

Metallicity and effective temperature of the secondary of RS Oph

The recurrent nova RS Oph undergoes nova eruptions every ~ 10-20years as a result of thermonuclear runaway on the surface of a white dwarf close to the Chandrasekhar limit. Both the progress of the eruption, and its aftermath, depend on the (poorly known) composition of the red giant in the RS Oph system. Our aim is to understand better the effect of the giant secondary on the recurrent nova eruption. Synthetic spectra were computed for a grid of M-giant model atmospheres having a range of effective temperatures 3200 < Teff < 4400 K, gravities 0 < log g < 1 and abundances -4 <[Fe/H] < 0.5, and fit to infrared spectra of RS Oph as it returned to quiescence after its 2006 eruption. We have modelled the infrared spectrum in the range 1.4-2.5 micron to determine metallicity and effective temperature of the red giant. We find Teff = 4100 +/- 100 K, log g = 0.0 +/- 0.5, [Fe/H] = 0.0 +/- 0.5, [C/H] = -0.8 +/- 0.2, [N/H] = +0.6 +/- 0.3 in the atmosphere of the secondary, and demonstrate that that inclusion of some dust `veiling' in the spectra cannot improve our fits.Comment: 6 pages, 5 figs, 1 table, to appear in A&