Stellar modelling of Spica, a high-mass spectroscopic binary with a β Cep variable primary component

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Stellar modelling of Spica, a high-mass spectroscopic binary with a β Cep variable primary component

© 2016 The Authors. Binary stars provide a valuable test of stellar structure and evolution, because the masses of the individual stellar components can be derived with high accuracy and in a model-independent way. In this work, we study Spica, an eccentric double-lined spectroscopic binary system with a β Cep type variable primary component. We use state-of-the-art modelling tools to determine accurate orbital elements of the binary system and atmospheric parameters of both stellar components. We interpret the short-period variability intrinsic to the primary component, detected on top of the orbital motion both in the photometric and spectroscopic data. The non-local thermodynamic equilibrium based spectrum analysis reveals two stars of similar atmospheric chemical composition consistent with the present-day cosmic abundance standard. The masses and radii of the stars are found to be 11.43 ± 1.15 M⊙ and 7.21 ± 0.75 M⊙, and 7.47 ± 0.54 R⊙ and 3.74 ± 0.53 R⊙ for the primary and secondary, respectively. We find the primary component to pulsate in three independent modes, of which one is identified as a radial mode, while the two others are found to be non-radial, low degree l modes. The frequency of one of these modes is an exact multiple of the orbital frequency, and the l = m = 2 mode identification suggests a tidal nature for this particular mode. We find a very good agreement between the derived dynamical and evolutionary masses for the Spica system to within the observational errors of the measured masses. The age of the system is estimated to be 12.5 ± 1 Myr.keywords: binaries: spectroscopic, stars: fundamental parameters, stars: individual: \ensuremathα Virginis, stars: oscillations, stars: variables: general, Astrophysics - Solar and Stellar Astrophysics adsurl: https://ui.adsabs.harvard.edu/#abs/2016MNRAS.458.1964T adsnote: Provided by the SAO/NASA Astrophysics Data Systemstatus: publishe

Strukturanalyse und Optimierung einer Vielbus Architektur zur Datenerfassung

Beschrieben wird der Entwurf eines optimierten Datenerfassungssystem fuer Streuexperimente am Speicherring COSY (COoler SYnchrotron Juelich). Das C40-System mit der Programmiersprache OCCAM-2 hat eine maximale Datenerfassungsrate von 26,66 Mbytes/s. (HP)The report describes the design of an optimized data acquisition system for scattering experiments at the COSY storage ring (COSY = COoler SYnchrotron Juelich). The C40 system uses the programming language OCCAM-2; it has a maximum data acquisition speed of 26.66 Mbytes/s. (HP)SIGLEAvailable from TIB Hannover: RA 831(3013) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman