BANANA IV: Two aligned stellar rotation axes in the young eccentric binary system EP Crucis: primordial orientation and tidal alignment

With observations of the EP Cru system, we continue our series of measurements of spin-orbit angles in eclipsing binary star systems, the BANANA project (Binaries Are Not Always Neatly Aligned). We find a close alignment between the sky projections of the rotational and orbital angular momentum vectors for both stars (beta_p = -1.8+-1.6 deg and |beta_s|<17 deg). We also derive precise absolute dimensions and stellar ages for this system. The EP Cru and DI Her systems provide an interesting comparison: they have similar stellar types and orbital properties, but DI Her is younger and has major spin-orbit misalignments, raising the question of whether EP Cru also had a large misalignment at an earlier phase of evolution. We show that tidal dissipation is an unlikely explanation for the good alignment observed today, because realignment happens on the same timescale as spin-orbit synchronization, and the stars in EP Cru are far from syncrhonization (they are spinning 9 times too quickly). Therefore it seems that some binaries form with aligned axes, while other superficially similar binaries are formed with misaligned axes.Comment: ApJ accepted, 10 pages, 7 figure

Pengaruh Kinerja Keuangan terhadap Tanggung Jawab Sosial Perusaahaan (Corporate Social Responsibility) pada Perusahaan Tambang yang Terdaftar di Bursa Efek Indonesia Periode 2015-2016

Corporate social responsibility (CSR) is one form of awareness of a company to the environment. Currently CSR aims to maximize profits but is also required to better accommodate the needs of the community and its stakeholders. This study aims to determine the effect of Return on assets, Return on equity, and Net profit margin on social responsibility at mining companies listed in the Indonesia Stock Exchange period 2015-2016. This research uses multiple regression analysis method. The results of this study indicate that during the period 2015-2016 ROA has no significant effect on CSR with a significant value of 0.986, ROE has no significant effect on CSR with a significant value of 0.191, and NPM has no significant effect on CSR with a significant value of 0.205

Synthesis of surfactant free stable nanofluids based on barium hexaferrite by pulsed laser ablation in liquid

Barium hexaferrite nanofluids based on five different solvents have been prepared by employing Pulsed Laser Ablation in Liquid (PLAL) at two different wavelengths of 532 nm and 1064 nm. They were then characterized using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), UV-Vis spectroscopy, and Vibrating Sample Magnetometry (VSM). The chemical states of the ablated nanoparticles were identified from XPS analysis and found to be matching with that of the target. The crystallinity of the nanoparticles were confirmed from high resolution TEM (HRTEM) images and SAED patterns. It is found that different liquid environments lead to the formation of barium ferrite nanoparticles with different particle diameters. The plausible mechanism involved in this process is discussed. This study can pave way for the synthesis of stable magnetic nanofluids of permanent magnets. Further, this technique could be utilized for tailoring the morphology of nanoparticles with a judicious choice of the solvents and other ablation parameter

Structural Properties of Co2+ Ion Doped Calcium Cadmium Phosphate Hydrate Nanophosphor

Inorganic nanophosphor materials have captivated the worldwide attention into the field of solid-state lighting emission displays, plasma display panels, light-emitting diodes, IR quantum counters, scintillation, etc. Nanotechnology is the foremost superior in the development of phosphors with definite size and shape. Alkali and alkaline earth phosphates are promising candidates for the inorganic phosphor materials. Manufacturing of nano-inorganic materials gained much interest due to their advance lighting applications. In this work, novel Co2+ doped Calcium Cadmium Phosphate hydrate nanophosphor (CaCdPH: Co2+) was synthesized by a traditional solid-state reaction technique. The synthesized sample was characterized by Powder XRD, SEM equipped with EDX and FTIR techniques. The hexagonal phase of the prepared CaCdPH: Co2+sample was confirmed by X-ray diffraction results, and the average crystallite size was evaluated. FTIR demonstrated the formation of vibrational modes ascribed to phosphate molecules and other hydroxyl groups. The morphologies of the CaCdPH: Co2+ nanophosphor was investigated by scanning electron microscopy. © 2020 Author(s).One of the authors, T. Rajyalakshmi is thankful to JNTU Kakinada, DIC for financial assistance in the MHRD project. Authors express their special thanks to UGC-DRS, DST-FIST - New Delhi for providing financial assistance to the Dept. of Physics, Acharya Nagarjuna University. And also acknowledge the service render by scientific officers of Kerala University and Yogi Vemana University for their help providing XRD and SEM instruments for sample recordings

The BANANA Project. V. Misaligned and Precessing Stellar Rotation Axes in CV Velorum

As part of the Binaries Are Not Always Neatly Aligned project (BANANA), we have found that the eclipsing binary CV Velorum has misaligned rotation axes. Based on our analysis of the Rossiter-McLaughlin effect, we find sky-projected spin-orbit angles of β[SUB]p[/SUB] = -52° ± 6° and β[SUB]s[/SUB] = 3° ± 7° for the primary and secondary stars (B2.5V + B2.5V, P = 6.9 days). We combine this information with several measurements of changing projected stellar rotation speeds (vsin i [SUB]sstarf[/SUB]) over the last 30 yr, leading to a model in which the primary star's obliquity is ≈65°, and its spin axis precesses around the total angular momentum vector with a period of about 140 yr. The geometry of the secondary star is less clear, although a significant obliquity is also implicated by the observed time variations in the vsin i [SUB]sstarf[/SUB]. By integrating the secular tidal evolution equations backward in time, we find that the system could have evolved from a state of even stronger misalignment similar to DI Herculis, a younger but otherwise comparable binary. Based on observations made with ESOs 2.2 m Telescopes at the La Silla Paranal Observatory under programme ID 084.C-1008 and under MPIA guaranteed time