We present the first evidence for the pulsations of primary components of four eclipsing binary systems. The TESS light curves of the targets are analyzed, the light and the absolute parameters are derived. Fourier analyses are applied to the residual data subtracted from the binary models to reveal the pulsational characteristics of the primaries. The components of the systems are compared to well-known binary systems of the same morphological type. The types of pulsational classes for the primaries are also discussed. Results show that CPD-30 740 and V1637 Ori are oscillating eclipsing Algol type binary stars, while HD 97329 and TYC 683-640-1 are found to be detached systems with pulsating primary components. We conclude that the primary components of the systems are pulsating stars.

We present the first evidence on the delta Sct type pulsations of the primary components of three eclipsing binaries IQ CMa, AW Men, and W Vol in the Transiting Exoplanet Survey Satellite (TESS) field. A comprehensive investigation of the binary properties is conducted. The light curves of the systems are analysed and the frequency analyses are performed to residual data. The systems are compared to the binaries of the same morphological types, and the primaries are examined in contrast to the delta Sct type pulsators. The results show that the systems are oscillating eclipsing Algol-type systems.

We present new photometric and spectroscopic observations and analyses for the eclipsing binary systems V1241 Tau and GQ Dra. Our photometric light and radial velocity curves analyses combining with the TESS light curves show that both are conventional semi-detached binary systems. Their absolute parameters are also derived. We present the $O-C$ analyses of the systems and we propose the most possible orbital period modulating mechanisms. Furthermore, Fourier analyses are applied to the photometric residual data of the systems to check for the pulsational behavior of the components. We conclude that the primary component of the system GQ Dra is a $δ$ Sct type pulsator with a dominant pulsation frequency of 18.58 d$^{-1}$ based on our $B$ filter residual light curve although it can not be justified by 30-minute cadence TESS data. No satisfactory evidence of pulsational behaviour for V1241 Tau was verified. Finally, the evolutionary tracks of the components of both systems are calculated, while their locations within evolutionary diagrams are compared with other Algol-type systems.

We present results of a study of variability of the marginal Am star HD 176843 observed in the Kepler field. Kepler photometry and ground-based spectroscopy are used to investigate the light variations of the star. HD 176843 is classified as a marginal Am star that shows delta Sct type pulsations. From an analysis of the Kepler time series, we find that the light curve of HD 176843 is dominated by three modes with frequencies f(1) = 0.1145, f(2) = 0.0162 and ,f(3) = 0.1078 d(-1). The amplitude of the radial velocity variations of about 10 km/s is much more than the radial velocity errors and allows us to conclude clear radial velocity variations. Using the radial velocity data and the adopted spectra, the orbital solution of HD 176843 is also obtained with an orbital period of 34.14 days. However, the available photometric data show no significant evidence for any possible motion in the binary system.

In this paper, effectiveness of twist varied wing configurations for aircraft control and performance is described. The primary variables investigated involved changing wing twist angle of a comparable Airbus A320 wing structure by identifying the ideal angle of twist. The aerodynamic performance and control of the morphing wing is characterised in AVL (Athena Vortex Lattice Method). In order to better understand the aerodynamic performance and control of twist morphing wing for diverse flight regimes, predetermined values of twist (-8°< ϕ <8°, in steps of ±2°) were examined. The results from this work indicate that if morphing wings were employed on aircraft, performance benefits could be achieved.

The high precision data obtained by the Kepler satellite allows us to detect hybrid-type pulsator candidates more accurately than the data obtained by ground–based observations. In this study, we present preliminary results on the new analysis of the Kepler light curve and high-resolution spectroscopic observations of the pulsating Am star KIC 9204718. Our tentative analysis shows that the star has hybrid-type pulsational characteristics.

Using the data from the public database of the All Sky Automated Survey (AsAs) we performed the very first light curve analyses of the three eclipsing binary systems AO Aqr, CW Aqr and ASAS 012206-4924.7. The physical parameters of the systems were determined by the PHOEBE (Prga and Zwitter, 2005) software. From an analysis of the ASAS data it was concluded that AO Aqr was found to be a contact binary system while CW Aqr and ASAS 012206-4924.7 were found to be near-contact and detached binaries, respectively. Finally, the locations of the components, corresponding to the estimated physical parameters, in the HR diagram were also discussed. (C) 2015 Elsevier B.V. All rights reserved.

The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar objects, the bright star HD 45975 was monitored for nearly two months by the CoRoT satellite. Independent analyses of the light curve provides evidence of monoperiodic variations with a frequency of 0.7572 c/d and a peak-to-peak amplitude of 2800 ppm. Multisite, ground-based spectroscopic observations overlapping the CoRoT observations show the star to be a long-period, single-lined binary. Furthermore, with the notable exception of mercury, they reveal the same periodicity as in photometry in the line moments of chemical species exhibiting strong overabundances (e.g., Mn and Y). In contrast, lines of other elements do not show significant variations. As found in other HgMn stars, the pattern of variability consists in an absorption bump moving redwards across the line profiles. We argue that the photometric and spectroscopic changes are more consistent with an interpretation in terms of rotational modulation of spots at the stellar surface. In this framework, the existence of pulsations producing photometric variations above the 50 ppm level is unlikely in HD 45975. This provides strong constraints on the excitation/damping of pulsation modes in this HgMn star.

We present results of new photometric observations of the contact binary system HI Pup as well as the radial velocity curve of the system. Time series multicolour photometry was obtained at the South African Astronomical Observatory (SAAO) using the 1-m Cassegrain Telescope. We applied a simultaneous solution to the BVRI light and radial velocity curves in order to determine the physical parameters of the system. From an analysis of the new multicolour data, the physical parameters were found to be M-1 = 1.22M(circle dot), M-2 = 0.23M(circle dot), R-1 = 1.44R(circle dot), R-2 = 0.67R(circle dot), L-1 = 33L(circle dot), L-2 = 0.7L(circle dot). Our solution confirms that HI Pup has a typical A-type W UMa binary system characteristics. (C) 2014 Elsevier B.V. All rights reserved.

AbstractPreliminary results on the analysis of the Kepler light curve and photometric ground-based time series of γ Dor star KIC 6462033 (TYC 3144-646-1, V = 10.83, P = 0.69686 d) are presented in order to determine pulsation frequencies.

We present results of an asteroseismic study on the gamma Dor type Kepler target KIC 6462033. Kepler photometry is used to derive the frequency content and principal modes. High-dispersion ground-based spectroscopy is also carried out in order to determine the atmospheric parameters and projected rotational velocity. From an analysis of the Kepler long cadence time series, we find that the light curve of KIC 6462033 is dominated by three modes with frequencies f(1) = 0.92527, f(2) = 2.03656 and f(3) = 1.42972 d(-1) as well as we detect more than a few hundreds of combination terms. However, two other independent frequencies appear to have lower amplitudes in addition to these three dominant terms. No significant peaks are detected in the region >5 d(-1). We therefore confirm that KIC 6462033 pulsates in the frequency range of gamma Dor type variables, and a future study will allow us to investigate modal behaviour in this star. (c) 2014 Elsevier B.V. All rights reserved.

Abstract We present new photometric observations of two eclipsing binary systems, V1241 Tau and GQ Dra. We use the following methodology: initially, the Wilson-Devinney code is applied to the light curves in order to determine the photometric elements of the systems. Then, the residuals are analysed using Fourier techniques. The results are the following. One frequency can be possibly attributed to a real light variation of V1241 Tau, while there is no evidence of pulsations in the light curve of GQ Dra.

We report on a multisite photometric campaign on the high-amplitude delta Scuti star V2367 Cyg in order to determine the pulsation modes. We also used high-dispersion spectroscopy to estimate the stellar parameters and projected rotational velocity. Time series multicolour photometry was obtained during a 98-d interval from five different sites. These data were used together with model atmospheres and non-adiabatic pulsation models to identify the spherical harmonic degree of the three independent frequencies of highest amplitude as well as the first two harmonics of the dominant mode. This was accomplished by matching the observed relative light amplitudes and phases in different wavebands with those computed by the models. In general, our results support the assumed mode identifications in a previous analysis of Kepler data.

We present results of a multisite photometric campaign on the high-amplitude delta Scuti star KIC 6382916 in the Kepler field. The star was observed over a 85-d interval at five different sites in North America and Europe during 2011. Kepler photometry and ground-based multicolour light curves of KIC 6382916 are used to investigate the pulsational content and to identify the principal modes. High-dispersion spectroscopy was also obtained in order to derive the stellar parameters and projected rotational velocity. From an analysis of the Kepler time series, three independent frequencies and a few hundred combination frequencies are found. The light curve is dominated by two modes with frequencies f(1) = 4.9107 and f(2) = 6.4314 d(-1). The third mode with f(3) = 8.0350 d(-1) has a much lower amplitude. We attempt mode identification by examining the amplitude ratios and phase differences in different wavebands from multicolour photometry and comparing them to calculations for different spherical harmonic degree, l. We find that the theoretical models for f(1) and f(2) are in a best agreement with the observations and lead to value of l = 1 modes, but the mode identification of f(3) is uncertain due to its low amplitude. Non-adiabatic pulsation models show that frequencies below 6 d(-1) are stable, which means that the low frequency of f(1) cannot be reproduced. This is a further confirmation that current models predict a narrower pulsation frequency range than actually observed.

We present new photometric observations of eclipsing binary systems V1241 Tau and GQ Dra. We use the following methodology: Initially, WD code is applied to the light curves, in order to determine the photometric elements of the systems. Then the residuals are analysed using Fourier Transformation techniques. The results show that one frequency can be barely attributed to the residual light variation of V1241 Tau, while there is no evidence of pulsation on the light curve of GQ Dra.

We report the evidence of a new beta Cephei type variable located in the Southern open cluster NGC 6200: ALS 3728. Spectroscopic and photometric observations of NGC 6200 stars were carried out at the South African Astronomical Observatory (SAAO) in 2011. It was found that ALS 3728 has a frequency of about 4.95 d(-1), with highest amplitude. The star also shows a remarkable stillstand phase just before its light maxima which is a typical characteristic occurring among these type of stars. Furthermore, a mode identification is applied for the dominant frequency calculated from the Fourier analysis. (C) 2013 Elsevier B.V. All rights reserved.

We present the results of a new investigation aimed to identify the pulsational characteristics of the Southern beta Cephei star ALS 3721. Spectroscopic and multicolour photometric data were acquired at the South African Astronomical Observatory (SAAO), South Africa in 2011. Frequency analysis showed that the oscillations of ALS 3721 could be attributed to the two main frequencies with higher significance. Stellar parameters and projected rotational velocity obtained by the spectra were also used to perform photometric mode identification. In order to determine spherical harmonic degrees (l), a principal method was followed by comparing the observed light amplitude ratios in different passbands with those computed from non-adiabatic pulsation models. In general case, therefore, the spherical harmonic degrees corresponding of the frequencies were found in the expected beta Cephei range. (C) 2013 Elsevier B.V. All rights reserved.