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We present three low-mass and one solar mass companions found around four intermediate-mass giants HD1695, HD120235, HD145316 and HD200004 from precise radial velocity measurements using the 1.5 m Russian-Turkish Telescope (RTT150) at the TUBITAK National Observatory of Turkey (TUG). The stellar parameters, which are effective temperature ( T eff ), surface gravity (logg) and metallicity ( [ Fe / H ] ), as well as rotational velocity (vsini) are obtained from spectral analysis. From the estimated stellar masses, the orbital parameters of the companions are also derived. We find two types of Keplerian solutions for the companion of HD120235: (1) periods 5522 days and eccentricity of e ∼ 0.93 , and (2) periods 1566 days and eccentricity of e ∼ 0.83 . From the abundances analysis HD1695 is found to be a metal-rich star with [ Fe / H ] > 0.1 , while HD200004 is a metal poor star with [ Fe / H ] - 0.2 . The other two stars, HD120235 and HD145316, have solar-like abundances with [ Fe / H ] ∼ 0.0 . Our stellar parameters and orbital solutions show that all of these stars are evolved intermediate-mass giants.

WOS: 000416942200014, For over 10 years, we have carried out a precise radial velocity (RV) survey to find substellar companions around evolved G, K-type stars to extend our knowledge of planet formation and evolution. We performed high precision RV measurements for the giant star HD 208897 using an iodine (l(2)) absorption cell. The measurements were made at TUBlTAK National Observatory (TUG; RTT150) and Okayama Astrophysical Observatory (OAO). For the origin of the periodic variation seen in the RV data of the star, we adopted a Keplerian motion caused by an unseen companion. We found that the star hosts a planet with a minimum mass of m(2) sin i = 1.40 M-J, which is relatively low compared to those of known planets orbiting evolved intermediate-mass stars. The planet is in a nearly circular orbit with a period of P = 353 days at about 1 AU distance from the host star. The star is metal rich and located at the early phase of ascent along the red giant branch. The photometric observations of the star at Ankara University Kreiken Observatory (AUKR) and the HlPPARCOS photometry show no sign of variation with periods associated with the RV variation. Neither bisector velocity analysis nor analysis of the Ca II and H alpha lines shows any correlation with the RV measurements., JSPS KAKENHIMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of ScienceGrants-in-Aid for Scientific Research (KAKENHI) [JP23244038, JP16H02169]; Scientific and Technological Research Council of Turkey (TUBlTAK) [114F099]; [3.6714.2017/8.9], This work was supported by The Scientific and Technological Research Council of Turkey (TUBlTAK), the project number of 114F099. Authors thank to TUG, KFU, and AST for partial support in using RTT150 (Russian-Turkish 1.5-m telescope in Antalya). This work was also supported by JSPS KAKENHI Grant Numbers JP23244038, JP16H02169. This work was funded by the subsidy 3.6714.2017/8.9 allocated to Kazan Federal University for the state assignment in the sphere of scientific activities.

We present multi-colour CCD observations of the low-temperature contact binaries, V453 Mon and V523 Cas. Their light curves are modelled to determine a new set of stellar and orbital parameters. Analysis of mid-eclipse times yields a new linear ephemeris for both systems. A period decrease (dP/dt=2.3×10−7 days/yr) in V453 Mon is discovered. V523 Cas, however, is detected to show a period increase (dP/dt=9.8×10−8 days/yr) because of the mass transfer of a rate of 1.1×10−7 M⊙ yr−1, from a less massive donor. Using these findings we can determine the physical parameters of the components of V523 Cas to be M 1=0.76 (3)M ⊙, M 2=0.39 (2)M ⊙, R 1=0.74 (2)R ⊙, R 2=0.55 (2)R ⊙, L 1=0.19 (3)L ⊙, L 2=0.14 (3)L ⊙, and the distance of system as 46(9) pc.

A site selection of potential observatory locations in Turkey have been carried out by using Multi-Criteria Decision Analysis (MCDA) coupled with Geographical Information Systems (GIS) and satellite imagery which in turn reduced cost and time and increased the accuracy of the final outcome. The layers of cloud cover, digital elevation model, artificial lights, precipitable water vapor, aerosol optical thickness and wind speed were studied in the GIS system. In conclusion of MCDA, the most suitable regions were found to be located in a strip crossing from southwest to northeast including also a diverted region in southeast of Turkey. These regions are thus our prime candidate locations for future on-site testing. In addition to this major outcome, this study has also been applied to locations of major observatories sites. Since no goal is set for the best, the results of this study is limited with a list of positions. Therefore, the list has to be further confirmed with on-site tests. A national funding has been awarded to produce a prototype of an on-site test unit (to measure both astronomical and meteorological parameters) which might be used in this list of locations., A site selection of potential observatory locations in Turkey have been carried out by using Multi-Criteria Decision Analysis (MCDA) coupled with Geographical Information Systems (GIS) and satellite imagery which in turn reduced cost and time and increased the accuracy of the final outcome. The layers of cloud cover, digital elevation model, artificial lights, precipitable water vapor, aerosol optical thickness and wind speed were studied in the GIS system. In conclusion of MCDA, the most suitable regions were found to be located in a strip crossing from southwest to northeast including also a diverted region in southeast of Turkey. These regions are thus our prime candidate locations for future on-site testing. In addition to this major outcome, this study has also been applied to locations of major observatories sites. Since no goal is set forthe best, the results of this study is limited with a list of positions. Therefore, the list has to be further confirmed with on-site tests. A national funding has been awarded to produce a prototype of an on-site test unit (to measure both astronomical and meteorological parameters) which might be used in this list of locations.

The AZT-22 telescope installed in Turkey (Antalia) was aligned and tested on stars by the Hartmann method. The rms normal deviation of an equivalent optical system is 0.040±0.016 µm. The circle of confusion is 0.40±0.04 arcsec in diameter at a 50% energy level.

The light curves, obtained by the authors of the present paper during the period 1978–1992, of the chromospherically active binary system RT Lac were examined. The average (B–V) colour indices were obtained and corrected for the interstellar extinction. Spectroscopic studies indicate that the less massive component may be taken as G8. The light curve analysis indicates that the less massive, larger component fills its corresponding Roche lobe. Both photometric and spectroscopic observations compel one to draw a conclusion that circumstellar matter does exist around the binary system. A colour excess caused by this matter is found to be 0.278 for B–V colour at mid–secondary eclipse. On the basis of photometric colour indices alone, the components of RT Lac are classified as G3–4 and G8. If we use the observed radial velocities of the less massive subgiant star from Ca II emission lines and from other optical lines we find for the mass of the more massive component as 1.34–1.70 M⊙. This mass range corresponds to the main sequence late F stars. The common envelope hypothesis and mass function and also blending of the spectral lines of more massive component point out that it should be at most a late F type main sequence star.

A small group of collaborators was established at the end of 2007 with the objective of starting an extra-solar planet search at the TUBITAK National Observatory of Turkey. High resolution spectra of some radial velocity standards and planet-harbouring stars have since been obtained using an iodine (I-2) absorption cell placed in front of the entrance slit of the Coude Echelle Spectrograph (CES) in the 1.5-m Russian-Turkish Telescope (RTT150). To determine precise radial velocity measurements for these stars, a new computer code was developed by one of the collaborators (MY) using an IDL (Interactive Data Language) programing platform specific to the RTT150's CES + I-2-cell data. This paper summarises the technical setup, the new code, the test observation results and the precision achieved in the radial velocity measurements. The results from radial velocity standards and planet-harbouring stars show that a precision of approximately 10 m s(-1) was achieved with the CES on the RTT150 during the three years of test observations. In addition, the instrumental profile (IP) characteristics of the CES on the RTT150 in this study were derived by modelling the observed B-star + I-2 spectra. The observed instrumental profiles were a typical Gaussian shape and exhibited small variations that depended on the position on the CCD and also varied between exposures, which affected the precision of the radial velocity measurements. (C) 2012 Elsevier B.V. All rights reserved.

A custom meteorological monitoring system was constructed to reliably monitor the meteorological parameters of the site of TUBITAK National Observatory (TUBITAK: The Scientific and Technical Research Council of Turkey). The site is located on a mountain top known as Bakįrlįtepe about 50 km west of the Antalya City at a height of 2547 m. The system has software (C-based data acquisition/archiving structure and PHP based WEB monitoring support) and micro-controller based control electronics, fiber based custom designed encoder sensors (for wind speed and direction) and transmission lines using fiberoptic to RS232 transcievers. The constructed system can be used in any robotic telescope project for data monitoring and alert system creation. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this study, we present photometric and spectroscopic variations of the extremely small mass ratio ($q\simeq 0.1$) late-type contact binary system \astrobj{V1191 Cyg}. The parameters for the hot and cooler companions have been determined as $M_\textrm{h}$ = 0.13 (1) $M_{\odot}$, $M_\textrm{c}$ = 1.29 (8) $M_{\odot}$, $R_\textrm{h}$ = 0.52 (15) $R_{\odot}$, $R_\textrm{c}$ = 1.31 (18) $R_{\odot}$, $L_\textrm{h}$ = 0.46 (25) $L_{\odot}$, $L_\textrm{c}$ = 2.71 (80) $L_{\odot}$, the separation of the components is $a$= 2.20(8) $R_{\odot}$ and the distance of the system is estimated as 278(31) pc. Analyses of the times of minima indicates a period increase of $\frac{dP}{dt}=1.3(1)\times 10^{-6}$ days/yr that reveals a very high mass transfer rate of $\frac{dM}{dt}=2.0(4)\times 10^{-7}$$M_{\odot}$/yr from the less massive component to the more massive one. New observations show that the depths of the minima of the light curve have been interchanged., Comment: Accepted for publication in New Astronomy, 16 pages, 2 figures, 4 tables

In this study, we present long term photometric variations of the close binary system \astrobj{GO Cyg}. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical parameters of the system are $M_1 = 3.0\pm0.2 M_{\odot}$, $M_2 = 1.3 \pm 0.1 M_{\odot}$, $R_1 = 2.50\pm 0.12 R_{\odot}$, $R_2 = 1.75 \pm 0.09 R_{\odot}$, $L_1 = 64\pm 9 L_{\odot}$, $L_2 = 4.9 \pm 0.7 L_{\odot}$, and $a = 5.5 \pm 0.3 R_{\odot}$. Our results show that \astrobj{GO Cyg} is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of $92.3\pm0.5$ years due to a third body whose mass is less than 2.3$M_{\odot}$. Finally a period variation rate of $-1.4\times10^{-9}$ d/yr has been determined using all available light curves., Accepted for publication in New Astronomy, 18 pages, 4 figures, 7 tables

In this study we determined precise orbital and physical parameters of the very short period low-mass contact binary system CC Com. The parameters are obtained by analysis of the new CCD data with the archival spectroscopic data. The physical parameters of the components derived as $M_\textrm{c}$ = 0.717(14) $M_{\odot}$, $M_\textrm{h}$ = 0.378(8) $M_{\odot}$, $R_\textrm{c}$ = 0.708(12) $R_{\odot}$, $R_\textrm{h}$ = 0.530(10) $R_{\odot}$, $L_\textrm{c}$ = 0.138(12) $L_{\odot}$, $L_\textrm{h}$ = 0.085(7) $L_{\odot}$, and the distance of the system is estimated as 64(4) pc. The times of minima obtained in this study and with those published before enable us to calculate the mass transfer rate between the components which is $1.6\times10^{-8}$ M$_{\odot}$yr$^{-1}$. Finally, we discuss the possible evolutionary scenario of CC Com., 5 pages, 2 figures

Two-colour photometric observations of the white-dwarf and K-dwarf eclipsing binary V471 Tau were made during the last four years. The resulting light curves and thirteen timings of mid-eclipse are presented. During the observations two flares were obtained on September 23 and December23, 1992. Both events occurred just after the fourth contact. The increment in the brightness was measured as 0 . m 067. The energy liberated by the flare was computed to be 5.43 × 1032 erg s−1 in the JohnsonB band, which amounts 1.13 times that of the total radiation of the K-dwarf.

We present ground-based photometry of the low-temperature contact binary BB Peg. We collected all the times of mid-eclipse available in the literature and combined them with those obtained in this study. Analyses of the data indicate a period increase of (3.0 ± 0.1) × 10-8 days yr -1. This period increase of BB Peg can be interpreted in terms of the mass transfer 2.4 × 10-8 M⊙ yr-1 from the less massive to the more massive component. The physical parameters have been determined as Mc = 1.42M⊙, Mh = 0.53 M⊙, Rc = 1.29 R⊙, Rh, = 0.83 R⊙, Lc = 1.86 L⊙, and L h = 0.94 L⊙ through simultaneous solutions of light and of the radial velocity curves. The orbital parameters of the third body, which orbits the contact system in an eccentric orbit, were obtained from the period variation analysis. The system is compared to the similar binaries in the Hertzsprung-Russell and mass-radius diagrams., Ege University Research Fund and TÜBİTAK National Observatory

WOS: A1997YK35600014, We present in this paper the results from a multisite photometric campaign devoted to the gamma Dor variable HD 164615. During the campaign data were collected in the Johnson and Stromgren photometric systems. A first search for sinusoidal periodicities yielded a three-term solution with frequencies f(1) = 1.2328, f(2) = 1.0899 and f(3) = 2.3501 d(-1), and a long-term trend f(4) = 0.1301 d(-1). The star may therefore be multiperiodic with each frequency related to a pulsation mode. However, a further examination of the curve provided evidence that the amplitude at the instant of maximum brightness is modulated. Alternatively, HD 164615 may be a monoperiodic variable with frequency f(1) = 1.2321 d(-1), showing amplitude modulation with frequency f(4) = 0.1301 d(-1). The presence in the power spectra of the coupling terms f(2) = f(1) - f(4) and f(3) = f(1) + f(4) - 1 supports the latter interpretation. In the monoperiodic case the previously given interpretation based on a spot carried through the visible disc by rotation still holds, provided that the spot is bright and evolves on a time-scale of a few days. However, similarities with other gamma Dor stars provide indirect indication in favour of the existence of a non-radial pulsation interpretation.

Photoelectric observations of the RS CVn-type double-lined spectroscopic and eclipsing binary ER Vul were obtained in B and V colours of Johnson’s UBV system, between 1981 and 1986. The light curves show that the system is sometimes very active and sometimes very quiet and have changes in short time intervals. The wave-like distortion which is superimposed on the light curves has been obtained. Moreover, small-amplitude light fluctuations in the light curves are noticable.

The photoelectricB andV colour observations of the β Lyrae-type eclipsing binary CN And were made on four nights at the Ege University Observatory. The new light elements, which were calculated by adding new times of minima obtained during the observations to the previous ones, were given. The light curve of the system varies cycle by cycle and the variation is discussed in some extent.

Two-colour photoelectric photometry of the eclipsing binary BD + 13o4708 was carried out. Several features such as asymmetry in the branches, light difference between the maxima, an eccentric orbit, a dip around phase 0.2 are distinctive. The new light elements of the system were computed using also the previous times of primary minima given by Walker (1988).

Photoelectric differentialB andV magnitudes of the eclipsing binary V1425 Cygni are presented yielding the complete photoelectric light curve of this relatively bright system. The improved light elements are calculated using the least-squares method.

B andV observations of the W Ursae Majoris-type eclipsing variable system AK Her were made on five nights at the Ege University Observatory. Several times of minima were obtained during the observations and the new light elements were calculated. The light-time period was found to be about 75.72 years. The light curve of the system appears to change in each cycle for both colours. The secondary minimum of the system seems to be a total eclipse with a duration of about 42 m .5.

WOS: 000079107500013, In this paper, we present the results of a multisite photometric campaign devoted to the gamma Doradus type variable HR 8799. From Johnson and Stromgren data, we were able to identify three independent frequencies (f(i) = 1.9791 cycle d(-1), f(2) = 1.7268 cycle d(-10) and f(3) = 1.6498 cycle d(-1)) as well as another signal, which we are able to identify as the coupling term between two of the frequencies (f(4) = f(1) - f(2) = 0.2479 cycle d(-1)). These four frequencies are able to account for all of the observed variations down to the la significance level. We discuss another possible interpretation of these frequencies using a model of quasi-stochastic amplitude modulation. In this scenario, we are able to show that HR 8799 might be pulsating with two independent frequencies, one of which undergoes amplitude modulation similar to other gamma Dor objects. In addition, we discuss a preliminary mode identification based on the observed colour curves. Finally, 18 simultaneous, high-resolution echelle spectra were collected on two nights and we qualitatively compare the radial velocities from these data with our photometry.