Z. Bozkurt

Apsidal motion in eccentric eclipsing binaries: CW Cephei, V478 Cygni, AG Persei, and IQ Persei

Aims. About thirty new times of minimum light recorded with photoelectric or CCD photometers were obtained for four earlytype eccentric-orbit eclipsing binaries CW Cep (P = 2. d 73, e = 0.029), V478 Cyg (2. d 88, 0.016), AG Per (2. d 03, 0.071), and IQ Per (1. 74, 0.076). Methods. Their O−C diagrams were analysed using all reliable timings found in the literature, and elements of apsidal motion were improved. Results. We confirm relatively short periods of apsidal motion of about 46, 27, 76, and 124 years for CW Cep, V478 Cyg, AG Per, and IQ Per, respectively. The corresponding internal structure constants, log k2, are then found to be –2.12, –2.25, –2.15, and –2.36, under the assumption that the component stars rotate pseudosynchronously. The relativistic effects are negligible, being up to 8% of the total apsidal motion rate in all systems. Using the light-time effect solution, we have predicted a faint third component orbiting with a period of about 39 years for CW Cep.

Chemical Compositions of Evolved Stars from Near-infrared IGRINS High-resolution Spectra. I. Abundances in Three Red Horizontal Branch Stars

We have derived elemental abundances of three field red horizontal branch stars using high-resolution (R

A Spectroscopic Survey of Field Red Horizontal-branch Stars

\simeq

Photometric solutions of some contact ASAS binaries

45,000), high signal-to-noise ratio (S/N

The WISE View of RV Tauri Stars

\gtrsim

Alfven waves in the inner polar coronal hole

200)

Spectroscopic and photometric observations of the selected Algol-type binaries -II. V2080 Cygni and V2365 Ophiuchi

H

Triple systems showing apsidal motion

and

Spectroscopic and photometric observations of the selected Algol-type binaries* -IV. V799 Cassiopeiae, BX Piscium and HD 172189

K

Spectroscopic and photometric observations of selected Algol‐type binaries – I. V1665 Aquilae and AG Arietis

band spectra obtained with the Immersion Grating Infrared Spectrograph (IGRINS). We have determined the abundances of 21 elements including