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Öğe Age Dependent Angular Momentum, Orbital Period and Total Mass of Detached Binaries(Cambridge Univ Press, 2012) Demircan, O.; Tuysuz, M.; Soydugan, Faruk; Bilir, S.The orbital angular momenta OAM (J) of detached binaries (including both cool and hot binaries) were estimated and nine subgroups were formed according to their OAM (3) distribution. The mean kinematical ages of all subgroups have been estimated by using their space velocity distributions and, thus, the age dependent variations of the mean OAM (3), orbital period (13), and total mass (M) of all subgroups were investigated. It was discovered that: i) The orbital period of detached binaries with radiative components decrease very slowly during the main sequence (MS) evolution. It is interesting that the large amount of mass loss is almost balanced by the OAM loss, and not much change in the orbital periods is observed. ii) The nuclear evolution of radiative components beyond the MS initiates the increase of the periods until the components have convective upper layers, i.e. until they become later than F5 IV, and the system becomes a cool binary with sub-giant or giant components. iii) The large co-rotating distance of the magnetically-driven wind in cool binaries (CAB) carries out a large amount of OAM and then the periods of such binaries decrease significantly, and the orbits shrink until another effect such as mass transfer dominates the period changes.Öğe Analysis of Exoplanet Light Curves(Astronomical Soc Pacific, 2015) Erdem, A.; Budding, E.; Rhodes, M. D.; Puskullu, Q.; Soydugan, Faruk; Soydugan, Esin; Tuysuz, M.We have applied the close binary system analysis package WINFITTER to a variety of exoplanet transiting light curves taken both from the NASA Exoplanet Archive and our own groundbased observations. WINFITTER has parameter options for a realistic physical model, including gravity brightening and structural parameters derived from Kopal's applications of the relevant Radau equation, and it includes appropriate tests for determinacy and adequacy of its best fitting parameter sets. We discuss a number of issues related to empirical checking of models for stellar limb darkening, surface maculation, Doppler beaming, microvariability, and transit time variation (TTV) effects. The Radau coefficients used in the light curve modeling, in principle, allow structural models of the component stars to be tested.Öğe Discovery of ? scuti type oscillations in two algol-type binaries: DY Aqr and Bg Peg(Hungarian Academy of Sciences (Konkoly Observatory), 2009) Soydugan, Esin; Soydugan, Faruk; Enyuz, T.; Puskullu, Q.; Tuysuz, M.; Bakis, V.; Bilir, S.[No abstract available]Öğe Effective Temperatures of Selected Main-Sequence Stars with the Most Accurate Parameters(Astronomical Soc Pacific, 2015) Soydugan, Faruk; Eker, Z.; Soydugan, Esin; Bilir, S.; Gokce, E. Y.; Steer, I.; Tuysuz, M.In this study we investigate the distributions of the properties of detached double-lined binaries (DBs) in the mass luminosity, mass radius, and mass-effective temperature diagrams. We have improved the classical mass luminosity relation based on the database of DBs by Eker et al. (2014a). Based on the accurate observational data available to us we propose a method for improving the effective temperatures of eclipsing binaries with accurate mass and radius determinations.Öğe Kinematic Properties of Chromospheric Active Binary Stars(Cambridge Univ Press, 2012) Tuysuz, M.; Soydugan, Faruk; Bilir, S.; Demircan, O.The kinematic behaviour of 362 chromospherically active binary stars (CABs) in the solar neighbourhood were investigated. The Third CABs Catalog by Eker et al. (2008) was used as the main source. The spatial distribution and the components of the Galactic space velocities of the programme stars were determined. The effects of differential rotation and Local Standard of Rest (LSR) were corrected for all systems. Forty probable moving group (MG) members were determined by Eggen's criteria. The kinematic age of the young systems, which are probable members of MGs, was calculated as 0.79 (0.21) Gyr and the rest of 322 field stars were found to have a kinematic age of 4.38 (1.1) Gyr. Field CABs were separated into two sub-groups: dwarf systems, which were formed by main sequence (dwarf) stars, and evolved systems included at least one evolved (giant or sub-giant) component. The kinematic age of 134 dwarf systems was calculated as 4.69 (0.75) Gyr and 4.15 (1.29) Gyr for 188 evolved CABs.Öğe MAIN-SEQUENCE EFFECTIVE TEMPERATURES FROM A REVISED MASS-LUMINOSITY RELATION BASED ON ACCURATE PROPERTIES(Iop Publishing Ltd, 2015) Eker, Z.; Soydugan, Faruk; Soydugan, Esin; Bilir, S.; Gokce, E. Yaz; Steer, I.; Tuysuz, M.The mass-luminosity (M-L), mass-radius (M-R), and mass-effective temperature (M-T-eff) diagrams for a subset of galactic nearby main-sequence stars with masses and radii accurate to <= 3% and luminosities accurate to <= 30% (268 stars) has led to a putative discovery. Four distinct mass domains have been identified, which we have tentatively associated with low, intermediate, high, and very high mass main-sequence stars, but which nevertheless are clearly separated by three distinct break points at 1.05, 2.4, and 7 M-circle dot within the studied mass range of 0.38-32 M-circle dot. Further, a revised mass-luminosity relation (MLR) is found based on linear fits for each of the mass domains identified. The revised, mass-domain based MLRs, which are classical (L proportional to M-alpha), are shown to be preferable to a single linear, quadratic, or cubic equation representing an alternative MLR. Stellar radius evolution within the main sequence for stars with M > 1 M-circle dot is clearly evident on the M-R diagram, but it is not clear on the M-T-eff diagram based on published temperatures. Effective temperatures can be calculated directly using the well known Stephan-Boltzmann law by employing the accurately known values of M and R with the newly defined MLRs. With the calculated temperatures, stellar temperature evolution within the main sequence for stars with M>1 M-circle dot is clearly visible on the M-T-eff diagram. Our study asserts that it is now possible to compute the effective temperature of a main-sequence star with an accuracy of similar to 6%, as long as its observed radius error is adequately small (<1%) and its observed mass error is reasonably small (<6%).Öğe New Discovered Pulsational Components in Algol Type Binaries and their Positions on the plane of Porb-Ppuls(Astronomical Soc Pacific, 2010) Soydugan, Esin; Soydugan, Faruk; Senyuz, T.; Tuysuz, M.; Bakis, V.; Bilir, S.; Cicek, C.In this study, eclipsing binaries located in the delta Scuti region of the instability strip were chosen from the list of candidate eclipsing binary systems with delta Scuti components. These candidate systems were photometrically observed and some of them were announced to be new Algol-type binaries with delta Scuti components. Although the pulsational variability could not be determined for some of the candidate Algols, pulsational components in EW Boo and DY Aqr have been discovered for the first time. The light curves of EW Boo and DY Aqr were analyzed to model the variations caused by the eclipsing behavior and then we determined the pulsational periods and amplitudes of the pulsating components in these Algols. The relationship between the pulsation and orbital periods of the eclipsing binaries were tested and discussed for the cases of EW Boo and DY Aqr.Öğe Photometric Study of Hot Jupiters: WASP-10 b and HAT-P-36 b(Astronomical Soc Pacific, 2015) Puskullu, C.; Soydugan, Faruk; Erdem, A.; Budding, E.; Soydugan, Esin; Tuysuz, M.; Rhodes, M.This work presents preliminary results of WINFITTER analyses of photometric observations of two hot Jupiters, WASP-10 b and HAT-P-36 b. According to these results, HAT-P-36 b has mean radius of R-p = 1.40 +/- 0.25 R-Jup, and transit parameter b = 0.44 +/- 0.09. WASP-10b shows some additional variations, and we therefore preferred to model its transit light curve with and without probable spot variations.Öğe Photometry of three chromospherically active stars: V340 Gem, SAO 62042 and FI Cnc(Elsevier, 2009) Erdem, A.; Budding, E.; Soydugan, Esin; Soydugan, Faruk; Dogru, S. S.; Dogru, D.; Tuysuz, M.We present a photometric study of three chromospherically active stars with long periods (V340 Gem, SAO 62042 and FI Cnc). The observations were made at the COMU Observatory in 2006 and 2007. We have made initial photometric analyses of V340 Gem and SAO 62042, which are newly discovered RS CVn-type SB1 binaries, and established the photometric variations of FI Cnc, which is a single G8III active star. Photometric rotation periods of these stars were obtained by analyzing their light variations. The light variations, observed over three or more consecutive orbital cycles, were investigated by using spot models with the program SPOT. We also discussed the surface differential rotation coefficient for the primary component of the SB1 binary star SAO 62042 in this study, using our own photometric period together with an orbital period taken from the literature. (C) 2008 Elsevier B.V. All rights reserved.Öğe The 2006/2007 photometric activity of three chromospherically active stars: V2075 Cyg, FG UMa and BM CVn(Elsevier Science Bv, 2009) Erdem, A.; Budding, E.; Soydugan, Esin; Bakis, H.; Dogru, D.; Dogru, S. S.; Tuysuz, M.We present new multiband CCD photometric observations of three chromospherically active stars with long periods (V2075 Cyg, FG UMa and BM CVn). The observations were made at the Canakkale Onsekiz Mart University Observatory in 2006 and 2007. We analyzed BVRI (Bessell) CCD observations of these three RS CVn-type SB1 binaries with the following three steps: (i) Photometric rotation periods were obtained by analyzing their light variations with a differential corrections method and a Fourier transform technique. (ii) Light variations. observed over three or more consecutive orbital cycles, were investigated by using dark (cool) spot models with the program SPOT. (iii) Surface differential rotation coefficients for the primary components of these binaries were derived using our own photometric periods together with orbital periods taken from the literature. (C) 2009 Elsevier B.V. All rights reserved.Öğe The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way(Cambridge Univ Press, 2014) Eker, Z.; Bilir, S.; Soydugan, Faruk; Gokce, E. Yaz; Soydugan, Esin; Tuysuz, M.; Senyuz, T.The most accurate stellar astrophysical parameters were collected from the solutions of the light and the radial velocity curves of 257 detached double-lined eclipsing binaries in the Milky Way. The catalogue contains masses, radii, surface gravities, effective temperatures, luminosities, projected rotational velocities of the component stars, and the orbital parameters. The number of stars with accurate parameters increased 67% in comparison to the most recent similar collection by Torres, Andersen, & Gimenez (2010). Distributions of some basic parameters were investigated. The ranges of effective temperatures, masses, and radii are 2 750 < T-eff (K)< 43 000, 0.18 < M/M-circle dot < 33, and 0.2 < R/R-circle dot < 21.2, respectively. Being mostly located in one kpc in the Solar neighborhood, the present sample covers distances up to 4.6 kpc within the two local Galactic arms, Carina-Sagittarius and Orion Spur. The number of stars with both mass and radius measurements better than 1% uncertainty is 93, better than 3% uncertainty is 311, and better than 5% uncertainty is 388. It is estimated from the Roche lobe filling factors that 455 stars (88.5% of the sample) are spherical within 1% of uncertainty.Öğe The early-type near-contact binary system V337 Aql revisited(Elsevier Science Bv, 2014) Tuysuz, M.; Soydugan, Faruk; Bilir, S.; Soydugan, Esin; Senyuz, T.; Yontan, T.The close binary V337 Aql consists of two early B-type components with an orbital period of 2.7339 d. New multi-band photometric observations of the system together with published radial velocities enabled us to derive the absolute parameters of the components. The simultaneous light and radial velocity curves solution yields masses and radii of M-1 = 17.44 +/- 0.31 M-circle dot and R-1 = 9.86 +/- 0.06 R-circle dot for the primary and M-2 = 7.83 +/- 0.18 M-circle dot and R-2 = 7.48 +/- 0.04 R-circle dot for the secondary component. Derived fundamental parameters allow us to calculate the photometric distance as 1355 +/- 160 pc. The present analysis indicates that the system is a near-contact semi-detached binary, in which a primary star is inside its Roche lobe with a filling ratio of 92% and the secondary star fills its Roche lobe. From O-C data analysis, an orbital period decrease was determined with a rate of -7.6 x 10(-8) yr(-1). Kinematic analysis reveals that V337 Aql has a circular orbit in the Galaxy and belongs to a young thin-disc population. (C) 2013 Elsevier B.V. All rights reserved.
