Astronomical Observations and Instrumentation

We report on the quiescent spectrum measured with Chandra ACIS-S of the transient, type I, X-ray-bursting neutron star Aql X-1, immediately following an accretion outburst. The neutron star radius, assuming a pure hydrogen atmosphere and a hard power-law spectrum, is R ∞ = 13.4 ( d /5 kpc) km. Based on the historical…

We perform an analysis of ∼80 000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit light curves from the Exoplanet Transit Database, public photometry from the literature, and some…

• ÖZGÜR BAŞTÜRK

A low-cost, solid-state inertial navigation system for robotics applications is described. Error models for the inertial sensors are generated and included in an extended Kalman filter (EKF) for estimating the position and orientation of a moving robot vehicle. A solid-state gyroscope and an accelerometer have been ev…

In this paper, we present the results of a multisite photometric campaign devoted to the γ Doradus type variable HR 8799. From Johnson and Strömgren data, we were able to identify three independent frequencies (f1 = 1.9791 cycle d−1, f2 = 1.7268 cycle d−1 and f3 = 1.6498 cycle d−1) as well as another signal, which we…

• VAROL KESKİN

Aims. We selected a large sample of O-B stars that were considered as (candidate) slowly pulsating B, β Cep, and Maia stars after the analysis of their hipparcos data. We analysed our new seven passband geneva data collected for these stars during the first three years of scientific operations of the mercator telescop…

• KADRİ YAKUT

We study the mid-egress eclipse timing data gathered for the cataclysmic binary HU Aquarii during the years 1993–2014. The (O−C) residuals were previously attributed to a single ∼7 Jupiter mass companion in ∼5 au orbit or to a stable two-planet system with an unconstrained outermost orbit. We present 22 new observatio…

• İLHAM NASIROĞLU

Pulse frequencies from the archival ROSAT observations of lE 2259+586 are presented. A short-term spin-up episode superposed on the secular spin-down trend is observed. Combining the previously published pulse frequencies, we estimate the variance of the angular velocity over a 15 yr span of observations. The level of…

Pulse frequencies from the archival ROSAT observations of lE 2259+586 are presented. A short-term spin-up episode superposed on the secular spin-down trend is observed. Combining the previously published pulse frequencies, we estimate the variance of the angular velocity over a 15 yr span of observations. The level of…

• ALTAN BAYKAL

ABSTRACT PSR J1024–0719 is a millisecond pulsar that was long thought to be isolated. However, puzzling results concerning its velocity, distance, and low rotational period derivative have led to a reexamination of its properties. We present updated radio timing observations along with new and archival optical data wh…

Abstract Since the onset of the “space revolution” of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The launch of the NASA Transiting Exoplanet Survey Satellite ( TESS ) mission has enabled seismic-based inferences to…

• MUTLU YILDIZ
• ZEYNEP ÇELİK ORHAN

In recent years, especially in industrial automation systems, in order for robots to understand their distances and positions according to the target, close to human vision, computer vision systems are needed. Computer vision close to human vision can only be created using stereo cameras. In this study, a computer vis…

Bound-bound absorption of polarized photons by hydrogen atoms is investigated for conditions expected in atmospheres of strongly magnetized neutron stars. Thermal motion of atoms across the strong magnetic field causes striking changes of the binding energies and oscillator strengths; these changes then lead to a new…