Nuclear reactions in shock wave front during supernova events

The new unique isotopic anomalous coponent of Xe(XeX) was found in the carbonaceous chondrites. It is enriched in light shielded isotopes (124Xe and 126Xe) and in heavy nonshielded isotopes (134Xe and 136Xe. All characteristics of Xe-X can be explained by a model of nucleosynthesis of the Xe isotopes in shock wave front passed through the He envelope during supernova events. The light isotopes are created by p process and the heavy isotopes are created by n process (slow r process). They were captured with high temperature carbon grains condensing by supernova shock waves

Determination of above-atmosphere dimensions of meteorites

Upper atmospheric dimensions of meteorite

Cosmogenic Mn-53 in meteorites

The distributions of the Mn-53 contents in 106 nonantarctic and 112 antarctic chondrites were analyzed. A correlation analysis of these distributions showed that the correlation coefficient is a maximum r sub max = 0.75 plus or minus 0.03) when the histogram for antarctic chondrites is displaced by 40 plus or minus 8 dpm kg-1Fe towards lower Mn-53 contents. The distribution of Mn-53 saturated contents in nonantarctic ordinary chondrites was investigated as a function of their radiation age (T). It is found that the Mn-53 average content is higher by (21 plus or minus 9)% in H-chondrites with radiation age T approximately 12 Myr than in thse with T 12 Myr. This effect can be attributed to the fact that a considerable proportion of H-chondrites with T 12 Myr originates from a comet or from the objects of Chiron like, with the orbits more inclined to the ecliptic plane and/or more extended, which caused their irradiation by cosmic rays of higher intensity

The nucleosynthesis of deterium and helium-3

A new model of the creation of D and 3He in supernova of the first generation was considered. It is based on the idea that a supernova event leads simultaneously to acceleration of particles in the shock wave front and to their interactions with supernova atmosphere matter. The D, 3He, Li, Be, B and bypassed isotopes are created in these interactions. The cosmic abundances of the bypassed isotopes with A or = 113 allowed to determine the integral proton flux I sub p (E sub p 25 MeV) = 5 x 10 to the 21/sq cm the spectral index - gamma = 3. The calculations of the D and 3He yields in various nuclear reactions at these irradiation conditions show that only the 4He(p,d)3He reaction leads to cosmic abundances of these isotopes on the assumption that all matter has been exposed

Primary cosmic rays on the lunar surface

Results are reported for determination of the galactic cosmic ray flux during various time intervals in the 1965-1972 period, on the basis of data from the instruments of a spacecraft that made a soft landing on the lunar surface, and from the radioactivity of samples returned by the spacecraft. During minimum solar activity (the second half of 1965 and the beginning of 1966) I sub 0 (E greater than or equal to 30 percent MeV/nucleon) was determined to be 0.43 (plus or minus 10 percent). These values, within the error limits of the determinations, agree with the corresponding values of galactic cosmic ray intensities determined by stratospheric measurements. The mean flux of galactic cosmic rays over the past million years is equal to I (E greater or equal to 100 MeV/nucleon) + 0.28 (plus or minus 20 percent). This value agrees with the mean flux of modulated cosmic rays during the period of the nineteenth solar cycle. The mean flux of solar protons between 1965 and 1972 was 2.46

The astrophysical interpretation of isotope anomalies in graphite and SiC grains of chondrites

The C, N, and Mg isotopic compositions in graphite and SiC grains of carbonaceous chondrites can be explained by nuclear processes in massive O,B stars of second generation passed a stage of WR star with intensive stellar wind, where grain condensation had taken place. The interstellar graphite and SiC grains with anomalous isotopic compositions of C, N, Ne, and Si and other elements of nucleosynthetic origin, found in non-equilibrated chondrites, are most suitable for determination of astro-physical objects, where nucleosynthesis had taken place. Two objects were examined: (1) massive O,B stars of second generation passed a stage of WR star with intensive stellar wind (O,B-WR model) and (2) low-mass stars (1 less than or equal to M/solar mass less than or equal to 3) during thermally pulsing asymptotic giant branch phase (TP-AGB model)

The radiation history of material returned by the Soviet automatic stations Luna 16 and Luna 20, according to track studies

Fission tracks formed by the vH (very heavy) nuclei group of solar and galactic cosmic rays have been studied in silicate minerals of the lunar regolith returned by the Luna 16 and Luna 20 unmanned spacecraft. It is shown that the material in the Luna 16 core sample, from a typical mare region of the lunar surface, has undergone stronger irradiation by cosmic rays than material returned a highland region by Luna 20. A low-irradiation component (about 10 percent of the total number of crystals) has been found in the Luna 20 core sample materials, which can possibly be attributed to material added to the main bulk of the regolith in the formation of the crater Apollonius C. From the track density distribution of crystals, as a function of depth in the regolith core sample, it follows that the process of formation of the upper layer of the regolith, both for the lunar mare and for the highland region, includes sequential layering of finely crushed crystalline matter and subsequent mixing of it by micrometeorite bombardment. A portion of the crystals with a very high track density may be a component added to the lunar surface from outer space

On origin of the olivine inclusions from the Kainsaz CO carbonaceous chondrite

Olivine inclusions and chondrules of Kainsaz were formed in a unique process of dust matter melting. The elemental abundances of four fractions of olivine (01) inclusions from Kainsaz were analyzed by INAA. The inclusions of fraction A (160 less than d less than 260 microns) have Fe-Ni grains, the inclusions of fractions B (100 less than d less than 160 microns), C (160 less than d less than 260 microns), and D (260 less than d less than 360 microns) do not. The average elemental enrichment factors relative to CI chondrite for each fraction and chondrules of Kainsaz is shown. The enrichment factors of siderophile Co, Ni, Ir, Au, and non-refractory Na in all fractions are less than 1. The factors of refractory Ca, Sc, La, Sm, and Yb are comparative with the corresponding values of O1 aggregates of Allende CV (average 4.76). For chondrules of Kainsaz these values are lower. Fraction A is enriched in Co, Ir, Au, and relative Ni and CI chondrites: Ir greater than Au greater than Co. The values of (Me/Ni)inc/(Me/Ni)CI are equal to 3.25 for Ir, 2.1 for Au, and 1.2 for Co. The superabundances in Ir and Au relative to Ni witness to formation of Fe-Ni grains of O1 inclusions by agglomeration of grains enriched in refractory metal with grains enriched in non-refractory metal (Au). The enrichments of fraction A in Ca, Sc, La, Sm, and Yb witness about presence of high-temperature phases in O1 inclusions

Light curve feature extraction from astronomical source

Астрономия входит в эпоху больших обзоров переменного неба, таких как Zwicky Transient Facility и грядущий Legacy Survey of Space and Time. Эти обзоры предназначены для мониторинга всей видимой части неба за несколько ночей. Для эффективной работы с такими объемами данных требуется автоматическое извлечение признаков кривых блеска для дальнейшего их использования в задачах классификации и определения физических параметров переменных источников. В данной работе мы представляем новую библиотеку на языке Python, предназначенную для извлечения 25 признаков кривых блеска переменных астрономических источников.Astronomy is entering the era of large surveys of the variable sky such as Zwicky Transient Facility and forthcoming Legacy Survey of Space and Time. These surveys are dedicated to observe the apparent celestial sphere in several days. The usage of an automatic extraction of light curve features is required to work effectively with such amount of data, especially in problems of classification and characterisation of variable sources. In this work, we present the new Python library for extraction of 25 light curve features of variable astronomic sources.Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 20-02-00779, при поддержке Междисциплинарной научно-образовательной школы Московского университета «Фундаментальные и прикладные исследования космоса»

Search for fast stellar flares in the Zwicky Transient Facility DR8

Вспышки красных карликов играют важную роль в изучении обитаемости экзопланет. Выборка, состоящая из достаточного количества объектов такого типа, не только бы внесла вклад в поиск потенциально обитаемых планет, но и помогла бы лучше изучить физическую природу вспышек красных карликов. В данной работе представлены методы обнаружения вспышек красных карликов и результаты их применения к данным 8-го релиза фотометрического обзора The Zwicky Transient Facility. При помощи описанных методов были найдены 20 кандидатов во вспыхивающие объекты c амплитудой вспышки более 1.5 магнитуды.Red dwarf flares are essential for the studying of the exoplanet’s habitability. The data sample, consisting of a sufficient number of objects, will not only help to find habitable planets candidates but also help to sort better through the physical nature of the red dwarf flares. In this work, we present the detection methods for the red dwarf flare candidates and apply them to the 8th data release of The Zwicky Transient Facility survey. The results consist of 20 candidates for the flaring objects having an amplitude larger than 1.5 magnitudes.Исследование выполнено при финансовой поддержке РФФИ и Национального центра научных исследований Франции в рамках научного проекта №21-52-15024. Анастасия Лаврухина — стипендиат некоммерческого фонда развития науки и образования «Интеллект»