Алгоритм предварительного анализа дифракционных спектров для нанокомпозитных материалов с примесью массивной фракции

This contribution is devoted to discussion of questions related to the influence of a possible contribution from a bulk material on the lineshape of elastic peaks observed in diffraction experiments at neutron and / or X-ray radiation scattering on nanoporous matrices containing substances embedded into their porous space (channels). The proposed algorithm permits to estimate the input of massive component into diffraction peaks using the analysis of the experimentally observed distortions of the lineshape of the Bragg peaks. This preliminary analysis greatly simplifies the profile analysis of nanocomposite diffraction patterns, especially for molecular sieves based on powders of SBA-15, MCM-41, MCM-48, etc. types.

V606 Cen: A Newly Formed Massive Contact Binary in a Hierarchical Triple System

V606 Centauri (V606 Cen) is an early B-type close binary with an orbital period of 1.4950935 days, and its complete light curves are very difficult to observe on the ground. By analyzing the continuous light curve obtained by TESS, we found that it is a marginal contact binary with a very low fill-out factor of about 2%. The O − C diagram of V606 Cen is constructed for the first time based on 118.8 yr of eclipse times. The O − C diagram has been found to show a downward parabolic change together with a cyclic oscillation with a semiamplitude of 0.0545 days and a period of 88.3 yr. The downward parabolic variation reveals a linear period decrease at a rate of dP/dt = −2.08 × 10−7 days yr−1 that can be explained by the mass transfer from the more massive component to the less massive one. Both the marginal contact configuration and the continuous period decrease suggest that V606 Cen is a newly formed contact binary via Case A mass transfer. The cyclic change in the O − C diagram can be explained by the light-travel time effect via the presence of a third body. The lowest mass of the tertiary companion is determined to be M 3 = 4.51 (±0.43) M ⊙ and the tertiary is orbiting around the central eclipsing binary in a nearly circular orbit (e = 0.33). All of the results indicate that V606 Cen is a newly formed massive contact binary in a hierarchical triple system.

Studies on the equatorial spot of G-type contact binary UV Lyn

New CCD photometric observations of G-type contact binary UV Lyn were obtained in 2006 and 2020, when the light curves (LCs) show positive O'Connell effect and negative O'Connell effect, especially. From the previous studies, the LCs by other ground-based telescope are variable from 1973 to 2020, particularly the magnitude difference between the two maxima. These phenomena indicate that the component is active in the past 47 years. In addition, under the monitoring of the space telescope of Transiting Exoplant Survey Satellite (TESS) from January to March in 2020, we fortunately find the continuous variations of O'Connell effect in every circle for the first time. The analysis also shows that in a short time, the positive O'Connell effect has been transformed into the negative one, which proves that there are stronger magnetic activities on the surface of the component. By using the Wilson-Devinney code with a spot model, these photometric solutions confirm UV Lyn is a shallow W-subtype contact binary with a cool equatorial spot on the less massive component. The successive variability of O'Connell effect possibly result from one equatorial cool spot shifting gradually along with time. We also investigate its \emph{O-C} curve from these continuous LCs, there is not obvious variation in such short time. while, the O’Connell effect as the indicator of the magnetic activity are possibly undergoing a periodic trend of a period of nearly 38 days. Comparing \emph{O-C} curve, we could find there is not relation between the period variation and magnetic activity.

The Census of Exoplanets in Visual Binaries: Population Trends from a Volume-Limited Gaia DR2 and Literature Search

We present results from an extensive search in the literature and Gaia DR2 for visual co-moving binary companions to stars hosting exoplanets and brown dwarfs within 200 pc. We found 218 planet hosts out of the 938 in our sample to be part of multiple-star systems, with 10 newly discovered binaries and 2 new tertiary stellar components. This represents an overall raw multiplicity rate of 23.2 ± 1.6 % for hosts to exoplanets across all spectral types, with multi-planet systems found to have a lower stellar duplicity frequency at the 2.2-σ level. We found that more massive hosts are more often in binary configurations, and that planet-bearing stars in multiple systems are predominantly observed to be the most massive component of stellar binaries. Investigations of the multiplicity of planetary systems as a function of planet mass and separation revealed that giant planets with masses above 0.1 MJup are more frequently seen in stellar binaries than small sub-Jovian planets with a 3.6-σ difference, a trend enhanced for the most massive (>7 MJup) short-period (<0.5 AU) planets and brown dwarf companions. Binarity was however found to have no significant effect on the demographics of low- mass planets (<0.1 MJup) or warm and cool gas giants (>0.5 AU). While stellar companion mass appears to have no impact on planet properties, binary separation seems to be an important factor in the resulting structure of planetary systems. Stellar companions on separations <1000 AU can play a role in the formation or evolution of massive, close-in planets, while planets in wider binaries show similar properties to planets orbiting single stars. Finally, our analyses indicate that numerous stellar companions on separations smaller than 1–3 arcsec likely remain undiscovered to this date. Continuous efforts to complete our knowledge of stellar multiplicity on separations of tens to hundreds of AU are essential to confirm the reported trends and further our understanding of the roles played by multiplicity on exoplanets.

The search for non-coevality among components of visual binaries

В данной работе предпринимается попытка обнаружить среди визуальных двойных звезд системы с компонентами разного возраста. Для этого сравниваются спектральные классы компонентов, а также их массы, оцененные из этой спектральной классификации. Применение этого простого метода к Каталогу орбитальных двойных звезд ORB6 позволило обнаружить тринадцать систем, у которых менее массивный компонент выглядит более проэволюционировавшим (т.е., два компонента, по-видимому, имеют разный возраст). Для уточнения результатов требуются дальнейшие исследования. The aim of this study is to find non-coeval pairs among visual binaries. For indication of non-coevality we compare spectral classes and masses of the components, estimated from the spectral classification. Applying this simple method to the Catalogue of orbital binaries ORB6, we found thirteen systems where less massive component is more evolved, and, consequently, the components are probably non-coeval. To prove non-coevality one needs a detailed investigation of the candidates.

V752 Cen - A triple-lined spectroscopic contact binary with sudden and continuous period changes

V752 Cen is a triple-lined spectroscopic contact binary. Its multi-colour light curves were obtained in the years 1971 and 2018, independently. Photometric analyses reveal that the two sets of light curves produce almost consistent results. It contains a W-subtype totally eclipsing binary, and its mass ratio and fill-out factor are q = 3.35(1) and $f = 29(2)\, {{\ \rm per\ cent}}$. The absolute elements of its two component stars were determined to be M1 = 0.39(2)M⊙, M2 = 1.31(7)M⊙, R1 = 0.77(1)R⊙, R2 = 1.30(2)R⊙, L1 = 0.75(3)L⊙ and L2 = 2.00(7)L⊙. The period of V752 Cen is 0.37023198 day. The 0.37-d period remained constant from its first measurement in 1971 until the year 2000. However, it changed suddenly around the year 2000 and has been increasing continuously at a rate of dP/dt = +5.05 × 10−7day · year−1 since then, which can be explained by mass transfer from the less massive component star to the more massive one with a rate of $\frac{dM_{2}}{dt}=2.52\times {10^{-7}}M_\odot /year$. The period variation of V752 Cen over the 48 years in which the period has been monitored is really unusual, and is potentially related to effects from the possible presence of a nearby third star or of a pair of stars in a second binary.

YZ Phoenicis: a very short period K-type contact binary with variation of the O’Connell effect and orbital period change

YZ Phe is a very short-period contact binary (Sp. = K2 V) with an orbital period of 0.2347 d near the short period limit (0.22 d). We present the complete light curves which photometric data were obtained from the 60 cm telescope of PROMPT-8 at CTIO in Chile during 2016 June to October and 2017 August. The photometric solutions were determined by using the Wilson & Devinney code and the results reveal that YZ Phe is a W-subtype shallow contact binary ($f\sim 10\,$, q = 2.635, or 1/q = 0.379 for W subtype) with rotational motion of a large hot spot on the more massive component, showing a strong O’Connell effect with variation of maxima in photometric time series at period of 4.20 yr and stellar cycle at period of 1.28 yr. By compiling all available eclipse times, the result shows a long-term period decrease at a rate of dP/dt = −2.64(±0.02) × 10−8 d yr−1, superimposed on a cyclic variation (A3 = 0.0081 d and P3 = 40.76 yr). This variation cannot be explained by the Applegate mechanism. Thus, the cyclic change may be interpreted as the light-travel time effect via the presence of a cool third body. Based on photometric solutions, the third light was detected as $2\,$ of the total light in V and I bands. These results support the existence of a third body. The long-term period decrease can be explained by mass transfer from the more massive component ($M_2 \sim 0.74\, M_{\odot }$) to the less massive one ($M_1 \sim 0.28\, M_{\odot }$) or plus angular momentum loss (AML) via magnetic braking. With 1/q < 0.4 and long-term period decrease, all factors suggest that YZ Phe is on the AML-controlled state and its fill-out factor will increase, as well as the system evolving into a deeper normal contact binary.

Mass Transfer and Intrinsic Light Variability in the Contact Binary MT Cas

First CCD photometry for the contact binary MT Cas is performed in 2013 in December. The spectral type of F8V is determined from the low-precision spectrum observed on 2018 Oct 22. With Wilson-Devinney code, the photometric solutions are deduced from VRc light curves (LCs) and AAVSO’s and ASAS-SN’s data, respectively. The results imply that MT Cas is a W-type weak-contact binary with a mass ratio of q=2.365(±0.005) and a fill-out factor of f=16.6(±1.2)%, respectively. The asymmetric LCs in 2013 are modeled by a dark spot on the more massive component. By analyzing the (O-C) curve, it is discovered that the orbital period may be undergoing a secular increase at a rate of dP/dt=1.12(±0.09)×10-8d yr-1, which may result from mass transfer from the less massive component to the more massive one. With mass transferring, MT Cas may evolve into a broken-contact configuration as predicted by TRO theory.

Fermionic Light Dark Matter Particles and the New Physics of Neutron Stars

Dark Matter constitutes most of the matter in the presently accepted cosmological model for our Universe. The extreme conditions of ordinary baryonic matter, namely high density and compactness, in Neutron Stars make these objects suitable to gravitationally accrete such a massive component provided interaction strength between both, luminous and dark sectors, at current experimental level of sensitivity. We consider several different DM phenomenological models from the myriad of those presently allowed. In this contribution, we review astrophysical aspects of interest in the interplay of ordinary matter and a fermionic light Dark Matter component. We focus in the interior nuclear medium in the core and external layers, i.e. the crust, discussing the impact of a novel dark sector in relevant stellar quantities for (heat) energy transport such as thermal conductivity or emissivities.