До біографії польського мандрівника Карла Качковського

Одним із забутих мандрівників, який залишив по собі опис побуту і традицій побачених ним народів та пам’яток історії Криму, і чия кримознавча спадщина, а надто – біографія, довгий час залишалася поза увагою українських дослідників, був поляк Карл Качковський. На сьогоднішній день окремі сторінки щоденника мандрівника видано в Криму, проте комплексної біографії К. Качковського у вітчизняній історіографії немає

A New Version of Reimers' law of Mass Loss Based on a Physical Approach

We present a new semi-empirical relation for the mass loss of cool stellar winds, which so far has frequently been described by "Reimers' law". Originally, this relation was based solely on dimensional scaling arguments without any physical interpretation. In our approach, the wind is assumed to result from the spill-over of the extended chromosphere, possibly associated with the action of waves, especially Alfven waves, which are used as guidance in the derivation of the new formula. We obtain a relation akin to the original Reimers law, but which includes two new factors. They reflect how the chromospheric height depends on gravity and how the mechanical energy flux depends, mainly, on effective temperature. The new relation is tested and sensitively calibrated by modelling the blue end of the Horizontal Branch of globular clusters. The most significant difference from mass loss rates predicted by the Reimers relation is an increase by up to a factor of 3 for luminous late-type (super-)giants, in good agreement with observations.Comment: 12 pages, 4 figures, accepted by ApJ Letter

Nucleosynthesis in Massive Stars With Improved Nuclear and Stellar Physics

We present the first calculations to follow the evolution of all stable nuclei and their radioactive progenitors in stellar models computed from the onset of central hydrogen burning through explosion as Type II supernovae. Calculations are performed for Pop I stars of 15, 19, 20, 21, and 25 M_sun using the most recently available experimental and theoretical nuclear data, revised opacity tables, neutrino losses, and weak interaction rates, and taking into account mass loss due to stellar winds. A novel ``adaptive'' reaction network is employed with a variable number of nuclei (adjusted each time step) ranging from about 700 on the main sequence to more than 2200 during the explosion. The network includes, at any given time, all relevant isotopes from hydrogen through polonium (Z=84). Even the limited grid of stellar masses studied suggests that overall good agreement can be achieved with the solar abundances of nuclei between 16O and 90Zr. Interesting discrepancies are seen in the 20 M_sun model and, so far, only in that model, that are a consequence of the merging of the oxygen, neon, and carbon shells about a day prior to core collapse. We find that, in some stars, most of the ``p-process'' nuclei can be produced in the convective oxygen burning shell moments prior to collapse; in others, they are made only in the explosion. Serious deficiencies still exist in all cases for the p-process isotopes of Ru and Mo.Comment: 53 pages, 17 color figures (3 as separate GIF images), slightly extended discussion and references, accepted by Ap

The most massive progenitors of neutron stars: CXO J164710.2-455216

The evolution leading to the formation of a neutron star in the very young Westerlund 1 star cluster is investigated. The turnoff mass has been estimated to be 35 Msun, indicating a cluster age ~ 3-5 Myr. The brightest X-ray source in the cluster, CXO J164710.2-455216, is a slowly spinning (10 s) single neutron star and potentially a magnetar. Since this source was argued to be a member of the cluster, the neutron star progenitor must have been very massive (M_zams > 40 Msun) as noted by Muno et al. (2006). Since such massive stars are generally believed to form black holes (rather than neutron stars), the existence of this object poses a challenge for understanding massive star evolution. We point out while single star progenitors below M_zams < 20 Msun form neutron stars, binary evolution completely changes the progenitor mass range. In particular, we demonstrate that mass loss in Roche lobe overflow enables stars as massive as 50-80 Msun, under favorable conditions, to form neutron stars. If the very high observed binary fraction of massive stars in Westerlund 1 (> 70 percent) is considered, it is natural that CXO J164710.2-455216 was formed in a binary which was disrupted in a supernova explosion such that it is now found as a single neutron star. Hence, the existence of a neutron star in a given stellar population does not necessarily place stringent constraints on progenitor mass when binary interactions are considered. It is concluded that the existence of a neutron star in Westerlund 1 cluster is fully consistent with the generally accepted framework of stellar evolution.Comment: 5 pages of text and 4 figures (submitted to Astrophysical Journal

Героическое в произведениях А.А. Фета о Крымской войне в контексте эстетической полемики ХIХ века

Проблемы героического в военной прозе и поэзии А.А Фета рассматриваются в контексте эстетической полемики второй половины Х1Х века. В ходе исследования литературно-критических материалов и произведений поэта делается попытка пересмотреть существование традиционных стереотипов относительно творчества и личной жизни художника-эстета и прийти к выводу: военная тематика поэта "чистого искусства" не была обособленной от всего его литературного наследия, она органически вписывалась в его эстетическую программу. Героическое в эстетике и творчестве А. Фета представлено наравне с категорией красоты как составляющей категории прекрасного.Проблеми героiчного в военiй прозi та поезii А.А.Фета разглядаються в контекстi літературної полемікі другоїї половини Х1Х сторіччя. В ході дослiдництва лiтературно-крiтичних матерiалiв та творiв поета робиться спроба переглянути iснування традицiйних стереотипiв вiдносно творчостi та особистого життя художника- естета та прийти до висновка: вiйськова тематика поета "чистого мистецтва" не була вiдокремленою вiд всii його спадщини, вона органiчно вписувалась в його естетичну програму. Героiчне в естетицi та творчостi А.Фета надано нарiвнi з категорiєю красоти, як складовоi категорii прекрасного.Heroic problems in war prose and poetry of A.A.Fet are examined in the context of literal controversy of the second part of the 19thcenturi. In the way of research of literal and critical materials and works of the poet the attempt is making to reexamine existence of formed stereotypes which are related to creative work and personal life of artist-design and go up to the conclusion that poet?s war subject-matter of "pure art" was not isolated from all his legacy. It enters organically into his aesthetic program

On the Binding Energy Parameter of Common Envelope Evolution. Dependency on the Definition of the Stellar Core Boundary during Spiral-in

According to the standard picture for binary interactions, the outcome of binaries surviving the evolution through a common envelope (CE) and spiral-in phase is determined by the internal structure of the donor star at the onset of the mass transfer, as well as the poorly-known efficiency parameter, eta_CE}, for the ejection of the H-envelope of the donor. In this Research Note we discuss the bifurcation point which separates the ejected, unprocessed H-rich material from the inner core region of the donor (the central part of the star which will later contract to form a compact object). We demonstrate that the exact location of this point is very important for evaluating the binding energy parameter, lambda, which is used to determine the post-CE orbital separation. Here we compare various methods to define the bifurcation point (core/envelope boundary) of evolved stars with masses 4, 7, 10 and 20 M_sun. We consider the specific nuclear energy production rate profile, the change in the mass-density gradient (Bisscheroux 1998), the inner region containing less than 10% hydrogen, the method suggested by Han et al. (1994) and the entropy profile. We also calculated effective polytropic index profiles. The entropy profile method measures the convective boundary (at the onset of flatness in the specific entropy) which is not equivalent to the core boundary for RGB stars. Hence, this method is not applicable for RGB stars, unless the actual bifurcation point of a CE is located at the bottom of the outer convection zone (resulting in larger values of lambda and larger post-CE orbital separations). On the AGB, where highly degenerate and condensed cores are formed, we find good agreement between the various methods, except for massive (20 M_sun) stars.Comment: 4 pages, 1 figure, A&A in pres

The Dutch resolution variant of the classical resolution of racemates by formation of diastereomeric salts:Family behaviour in nucleation inhibition

The resolution of racemates through their diastereomeric salts can be positively affected by the addition of small amounts of suitable nucleation inhibitors. This discovery is a logical extension of “Dutch Resolution”, in which equimolar amounts of resolving agents that are members of the same family (i.e., structurally related) are used. We conducted a systematic search for nucleation inhibitors of the resolving agent 1-phenylethylamine. A wide range of amines that bear possible family resemblances to 1-phenylethylamine was investigated. It was found that (R)-1-phenylbutylamine is a good inhibitor of (R)-1-phenylethylamine. Results of turbidity measurements showed that, for the model case of mandelic acid resolution, the chief effect of this inhibitor was to widen the metastable zone for the more soluble diastereomer. This observation is in accordance with previous experience. Further scouting for possible family members revealed a wide variation in the effectiveness of inhibitors, dependent on their structure. By far the most effective inhibitors are bifunctional 1-phenylethylamine and/or 1-phenylbutylamine analogues. The effect of racemic inhibitors was found to approach that of enantiomerically pure inhibitors of the same absolute configuration of the 1-phenylethylamine used for resolution. The most effective inhibitors were tested for the resolution of a structural variety of racemates, and were shown to be broadly applicable.