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Formation and evolution of binary systems with compact objects
In: Dissertationes astronomiae Universitatis Tartuensis 9
Thermodynamics of grain boundary adsorption in binary systems with limited solubility
In: Zeitschrift für Metallkunde, Band 96, Heft 10, S. 1094-1098
APPLICATION OF THE UNIFAC MODEL TO BINARY SYSTEMS CONTAINING AROMA COMPOUNDS
In: Proceedings of the Estonian Academy of Sciences. Chemistry, Band 41, Heft 2, S. 62
A VLT/FLAMES survey for massive binaries in Westerlund 1 VIII. Binary systems and orbital parameters
Context. The galactic cluster Westerlund 1 contains a rich population of evolved, massive stars. A high binary fraction has been inferred from previous multi-wavelength observations. Aims. We use multi-epoch spectroscopy of a large sample of early-type stars in Westerlund 1 to identify new binaries and binary candidates in the cluster. Methods. VLT/FLAMES was used with the GIRAFFE spectrograph in HR21 mode to obtain spectra of ∼100 OB stars over a 14-month baseline in 2008 and 2009, supplemented with follow-up observations in 2011 and 2013. Radial velocities were obtained from strong Paschen series absorption lines in the I-band. Results. We identify 20 new OB I–III binaries, a WN9h binary, and a WC9d binary, greatly increasing the number of directly confirmed binary systems in Westerlund 1, while 12 O9−9.5 Iab−III stars are identified as candidate binaries based on radial velocity changes that are inconsistent with photospheric variability. The 173.9 day SB1 W1030 represents the first longer-period system identified in the cluster, while the determination of a 53.95 day period for W44 (WR L) makes it the first Wolf-Rayet binary in Westerlund 1 with a confirmed orbital period greater than ten days. Our results suggest the binary fraction in the OB population is at least ∼40%, and may be significantly higher. Conclusions. These results demonstrate that binary systems can be effectively identified in the population of OB I−III stars evolving off the main sequence in Westerlund 1. Future multi-epoch surveys will be able to fully characterise this population. ; This research is partially supported by the Spanish Government Ministerio de Ciencia, Innovación y Universidades under grant PGC2018-093741-B-C21 (MICIU/AEI/FEDER, UE). I.N. is also supported by the Generalitat Valenciana through grant PROMETEO/2019/041. F.N. acknowledges financial support through Spanish grant PID2019-105552RB-C41 (MINECO/MCIU/AEI/FEDER) and from the Spanish State Research Agency (AEI) through the Unidad de Excelencia "María de ...
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Thermodynamic Study of Binary Systems Containing Carbon Dioxide and Associated Gases Using Molecular Simulation Techniques
In: 14th Greenhouse Gas Control Technologies Conference Melbourne 21-26 October 2018 (GHGT-14)
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Working paper
Structure formation in binary systems hydrolysis lignin – oil product and thermochemical transformations of composites on their basis
In: Žurnal Belorusskogo gosudarstvennogo universiteta: Journal of the Belarusian State University. Sociologiâ. Sociology, Heft 1, S. 3-18
ISSN: 2617-3980
Rheological properties of hydrophobized hydrolysis lignin dispersions in tank oil, diesel fuel, and industrial oil were under study. It was found that at the hydrolysis lignin content of more than 20 wt. %, a coagulation-thixotropic structure with a pseudoplastic flow pattern is formed. The parameters of structure formation calculated within the theory of elastic flocks made it possible to characterize dispersions in diesel fuel as least structured. In accordance with the theory of diffusion-limited aggregation, a computer model of the aggregate of hydrolytic lignin particles in diesel fuel was calculated and its internal structure was established using the proposed method of computer analysis of digital photographs. Machine learning was used to predict the optimal conditions for the production of mesoporous activated carbons from hydrolysis lignin. Experimentally obtained carbons are characterized by total pore volume of (0.95 ± 0.05) cm3/g and BET surface area of (1700 ± 85) m2/g, that corresponds to the predicted parameters.
Efficient adsorption of Cu2+ and Cd2+ from groundwater by MgO-modified sludge biochar in single and binary systems
In: Environmental science and pollution research: ESPR, Band 31, Heft 6, S. 9237-9250
ISSN: 1614-7499
Red supergiant stars in binary systems. I. Identification and characterisation in the small magellanic cloud from the UVIT ultraviolet imaging survey
We aim to identify and characterise binary systems containing red supergiant (RSG) stars in the Small Magellanic Cloud (SMC) using a newly available ultraviolet (UV) point source catalogue obtained using the Ultraviolet Imaging Telescope (UVIT) on board AstroSat. We select a sample of 560 SMC RSGs based on photometric and spectroscopic observations at optical wavelengths and cross-match this with the far-UV point source catalogue using the UVIT F172M filter, finding 88 matches down to mF172M = 20.3 ABmag, which we interpret as hot companions to the RSGs. Stellar parameters (luminosities, effective temperatures and masses) for both components in all 88 binary systems are determined and we find mass distributions in the ranges 6.1 < M/M⊙ < 22.3 for RSGs and 3.7
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MONOS: Multiplicity Of Northern O-type Spectroscopic systems - II. Orbit review and analysis for 35 single-lined spectroscopic binary systems and candidates
Context. Massive stars are a key element for understanding the chemical and dynamical evolution of galaxies. Stellar evolution is conditioned by many factors: Rotation, mass loss, and interaction with other objects are the most important ones for massive stars. During the first evolutionary stages of stars with initial masses (i.e., MZAMS) in the MZAMS ∼ 18–70 M⊙ range, they are of spectral type O. Given that stars in this mass range spend roughly 90% of their lifetime as O-type stars, establishing the multiplicity frequency and binary properties of O-type stars is crucial for many fields of modern astrophysics. Aims. The aim of the MONOS project is to collect information to study northern Galactic O-type spectroscopic binaries. In this second paper, we tackle the study of the 35 single-line spectroscopic binary (SB1) systems identified in the previous paper of the series, analyze our data, and review the literature on the orbits of the systems. Methods. We have measured ∼4500 radial velocities for a selection of diagnostic lines for the ∼700 spectra of the studied systems in our database, for which we have used two different methods: a Gaussian fit for several lines per object and cross-correlation with synthetic spectra computed with the FASTWIND stellar atmospheric code. We have also explored the photometric data delivered by the TESS mission to analyze the light curve (LC) of the systems, extracting 31 of them. We have explored the possible periods with the Lomb-Scargle method and, whenever possible, calculated the orbital solutions using the SBOP and GBART codes. For those systems in which an improved solution was possible, we merged our radial velocities with those in the literature and calculated a combined solution. Results. As a result of this work, of the 35 SB1 systems identified in our first paper we have confirmed 21 systems as SB1 with good orbits, discarded the binary nature of six stars (9 Sge, HD 192 281, HDE 229 232 AB, 68 Cyg, HD 108, and α Cam), and left six stars as inconclusive due to a lack of data. The remaining two stars are 15 Mon Aa, which has been classified as SB2, and Cyg OB2-22 C, for which we find evidence that it is most likely a triple system where the O star is orbiting an eclipsing SB1. We have also recalculated 20 new orbital solutions, including the first spectroscopic orbital solution for V747 Cep. For Cyg OB2-22 C, we have obtained new ephemerides but no new orbit. ; E.T.P., I.N.D. and S.S.D. acknowledge support from the Spanish Government Ministerio de Ciencia through grant AYA2015-68 012-C2-1/2-P. E.T.P. and J.M.A. acknowledge support from the Spanish Government Ministerio de Ciencia through grants AYA2016-75 931-C2-2-P and PGC2018-095 049-B-C22. R.H.B. acknowledges support from the ESAC Faculty Council Visitor Program and ANID FONDECYT Project 1211903. G.H. acknowledges support from the Spanish Government Ministerio de Ciencia through grant PGC2018-95049-B-CC22 and ESA Contract No. 4000-126507/19/ES/CM. This research has made use of the SIMBAD database, operated at CDS (Strasbourg, France), NASA's Astrophysics Data System Bibliographic Services and the Python programming language (Python Software Foundation), Lightkurve, a Python package for Kepler and TESS data analysis (Lightkurve Collaboration 2018).
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THE APPLICATICN ОЕ THE GROUP CONTRIBUTION METHOD TO PREDICTING AND CALCULATING THE KINEMATIC VISCOSITY OF BINARY SYSTEMS CONTAINING UNSATURATED HYDROCARBONS
In: Proceedings of the Estonian Academy of Sciences. Chemistry, Band 42, Heft 2, S. 69
Biosorption of chromium (VI), iron (II), copper (II), and nickel (II) ions onto alkaline modified Chlorella vulgaris and Spirulina platensis in binary systems
In: Environmental science and pollution research: ESPR, Band 29, Heft 41, S. 62514-62536
ISSN: 1614-7499
Adaptation of advanced physical models to interpret the adsorption isotherms of lead and cadmium ions onto activated carbon in single-compound and binary systems
In: Environmental science and pollution research: ESPR, Band 29, Heft 41, S. 62507-62513
ISSN: 1614-7499
On non-binary traceability set systems
We introduce non-binary IPP set systems with traceability properties that have IPP codes and binary IPP set systems with traceability capabilities as particular cases. We prove an analogue of the Gilbert–Varshamov bound for such systems. ; Marcel Fernandez: The work of M. Fernández has been supported by the Spanish Government Grant TEC2015- 68734-R and Catalan Government Grant SGR 782. ; Peer Reviewed ; Postprint (author's final draft)
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