Type Ia Supernovae inside Planetary Nebulae: Shaping by Jets

Using 3D numerical hydrodynamical simulations we show that jets launched prior to type Ia supernova (SN Ia) explosion in the core-degenerate scenario can account for the appearance of two opposite lobes ('Ears') along the symmetry axis of the SN remnant (SNR). In the double-degenerate and core-degenerate scenarios the merger of the two degenerate compact objects is very likely to lead to the formation of an accretion disk, that might launch two opposite jets. In the CD scenario these jets interact with the envelope ejected during the preceding common envelope phase. If explosion occurs shortly after the merger process, the exploding gas and the jets will collide with the ejected nebula, leading to SNR with axisymmetric components including 'Ears'. We also explore the possibility that the jets are launched by the companion white dwarf prior to its merger with the core. This last process is similar to the one where jets are launched in some pre-planetary nebulae. The SNR 'Ears' in this case are formed by a spherical SN Ia explosion inside an elliptical planetary nebula-like object. We compare our numerical results with two SNRs - Kepler and G299.2-2.9.Comment: 17 pages, 8 figure

Modeling SNR G1.9+0.3 as a Supernova Inside a Planetary Nebula

Using 3D numerical hydrodynamical simulations we show that a type Ia supernova (SN Ia) explosion inside a planetary nebula (PN) can explain the observed shape of the G1.9+0.3 supernova remnant (SNR) and its X-ray morphology. The SNR G1.9+0.3 morphology can be generally described as a sphere with two small and incomplete lobes protruding on opposite sides of the SNR, termed "ears", a structure resembling many elliptical PNe. Observations show the synchrotron X-ray emission to be much stronger inside the two ears than in the rest of the SNR. We numerically show that a spherical SN Ia explosion into a circumstellar matter (CSM) with the structure of an elliptical PN with ears and clumps embedded in the ears can explain the X-ray properties of SNR G1.9+0.3. While the ejecta has already collided with the PN shell in most of the SNR and its forward shock has been slowed down, the ejecta is still advancing inside the ears. The fast forward shock inside the ears explains the stronger X-ray emission there. SN Ia inside PNe (SNIPs) seem to comprise a non-negligible fraction of resolved SN Ia remnants.Comment: Revised version. 19 pages, 8 figures. Accepted to MNRA

Numerical simulations of wind-equatorial gas interaction in eta Carinae

We perform three-dimensional gas-dynamical simulations and show that the asymmetric morphology of the blue and red-shifted components of the outflow at hundreds of astronomical units (AU) from the massive binary system eta Carinae can be accounted for from the collision of the free primary stellar wind with the slowly expanding dense equatorial gas. Owing to the very complicated structure of the century-old equatorial ejecta, that is not fully spatially resolved by observations, we limit ourselves to modelling the equatorial dense gas by one or two dense spherical clouds. Because of that we reproduce the general qualitative properties of the velocity maps, but not the fine details. The fine details of the velocity maps can be matched by simply structuring the dense ejecta in an appropriate way. The blue and red-shifted components are formed in the post-shock flow of the primary wind, on the two sides of the equatorial plane, respectively. The fast wind from the secondary star plays no role in our model, as for most of the orbital period in our model the primary star is closer to us. The dense clouds are observed to be closer to us than the binary system is, and so in our model the primary star faces the dense equatorial ejecta for the majority of the orbital period.Comment: MNRAS, in pres

Planning the experiment and optimization of the content of nanoadition in polypropylene monothreads

Планування експерименту та оптимізація складу композиції поліпропілен/бінарна нанодобавка щодо одержання поліпропіленових монониток з високими механічними та антимікробними властивостями. Для планування експерименту застосовано симплексно-гратковий метод у псевдокоординатах. Оптимізацію вмісту нанодобавки проведено з використанням критерію Харрингтона. Методом математичного моделювання досліджено вплив нанодобавки срібло/кремнезем (Ag/SiO2) на властивості поліпропіленових (ПП) монониток та оптимізовано склад композиції для їх формування. Створена математична модель, що встановлює взаємозв’язок між вмістом компонентів суміші та властивостями нанонаповнених ПП ниток. Модифіковані мононитки, сформовані з оптимального складу композиції ПП/нанодобавка, поєднують високі міцність, еластичність та проявляють антимікробну дію

A method of forming composite structures using in situ -formed liquid crystal polymer fibers in a thermoplastic matrix

A new high speed and potentially economical method of creating a composite material and structures therefrom is tested. The method consists of spinning composite fibers from a melt blend of a thermoplastic with a liquid crystal polymer (LCP). Discontinuous fibrils of the LCP are formed in situ during the spinning process. These composite fibers are aligned and placed in a mold and heated to melt the thermoplastic matrix, but not the fibrils. A finished composite structure reinforced by the LCP fibrils is obtained when the thermoplastic phase is consequently consolidated. Our experiments show the proposed process is reasonable for an easily processed polystyrene matrix. High modulus fibrils with essentially infinite L/D ratios are readily produced in the extrusion process using 40 wt% of a wholly aromatic poly(ester-co-amide) LCP from Celanese. The integrity and alignment of the LCP fibrils is retained in the molding step. Mechanical tests show that the fibers produced by high shear rate processing have a stiffness approaching 23 GPa and match an axial rule-of-mixtures theory. The use of polystyrene resulted in brittleness. Molded composite plates exhibit slightly lower stiffness and significantly lower strength than individual fibers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38419/1/750110103_ftp.pd

Observational Constraints on the Common Envelope Phase

The common envelope phase was first proposed more than forty years ago to explain the origins of evolved, close binaries like cataclysmic variables. It is now believed that the phase plays a critical role in the formation of a wide variety of other phenomena ranging from type Ia supernovae through to binary black holes, while common envelope mergers are likely responsible for a range of enigmatic transients and supernova imposters. Yet, despite its clear importance, the common envelope phase is still rather poorly understood. Here, we outline some of the basic principles involved, the remaining questions as well as some of the recent observational hints from common envelope phenomena - namely planetary nebulae and luminous red novae - which may lead to answering these open questions.Comment: 29 pages, 8 figures. To appear in the book "Reviews in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds. Kabath, Jones and Skarka; publisher Springer Nature) funded by the European Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-03556