Filiz Kahraman Alicavus

Filiz Kahraman Alicavus
Çanakkale Onsekiz Mart Üniversitesi | ÇOMÜ

PhD

About

44
Publications
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212
Citations
Introduction
Filiz Kahraman Alicavus currently works at Nicolaus Copernicus Astronomical Center. Filiz does research in Observational Astronomy, Astrophysics and Astronomy. Their most recent publication is 'High-resolution spectroscopy and abundance analysis of Delta Scuti stars near the Gamma Doradus instability strip'.

Publications

Publications (44)
Preprint
Pulsating stars are remarkable objects for stellar astrophysics. Their pulsation frequencies allow us to probe the internal structure of stars. One of the most known groups of pulsating stars is $\delta$ Scuti variables which could be used to understand the energy transfer mechanism in A-F type stars. Therefore, in the current study, we focused on...
Article
Existence of pulsating stars in eclipsing binaries has been known for decades. These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipsing and pulsation variations. The eclipsing binaries are the only way to directly measure the mass and radius of stars with a good accuracy (≤1%), while the pulsatio...
Preprint
Existence of pulsating stars in eclipsing binaries has been known for decades. These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipsing and pulsation variations. The eclipsing binaries are the only way to directly measure the mass and radius of stars with a good accuracy ($\leq$1\%), while the pu...
Preprint
Pulsating stars occupy a significant place in the H-R diagram and it was thought that all stars inside the classical instability strip should pulsate. However, recent studies showed that there are many non-pulsating stars placed inside the classical instability strip. The existence of these non-pulsating stars is still a mystery. To deeply understa...
Preprint
Full-text available
Oscillating eclipsing Algols (oEAs) are remarkable systems which allow us to determine accurate fundamental stellar parameters (mass, radius) and probe the stellar interiors through pulsations. TZ\,Dra is an oEA system containing a $\delta$ Scuti component. To examine particular characteristics of such close systems including pulsations and mass tr...
Article
Oscillating eclipsing Algols (oEAs) are remarkable systems which allow us to determine accurate fundamental stellar parameters (mass, radius) and probe the stellar interiors through pulsations. TZ Dra is an oEA system containing a δ Scuti component. To examine particular characteristics of such close systems including pulsations and mass transfer,...
Article
Pulsating stars occupy a significant place in the H-R diagram and it was thought that all stars inside the classical instability strip should pulsate. However, recent studies showed that there are many non-pulsating stars located inside the classical instability strip. The existence of these non-pulsating stars is still a mystery. To deeply underst...
Preprint
Full-text available
We present a study based on the high-resolution spectroscopy and K2 space photometry of five chemically peculiar stars in the region of the open cluster M44. The analysis of the high-precision photometric K2 data reveals that the light variations in HD 73045 and HD 76310 are rotational in nature and caused by spots or cloud-like co-rotating structu...
Article
Full-text available
We report the discovery of the third tidally tilted pulsator, TIC 63328020. Observations with the TESS satellite reveal binary eclipses with an orbital period of 1.1057 d, and δ Scuti-type pulsations with a mode frequency of 21.09533 d−1. This pulsation exhibits a septuplet of orbital sidelobes as well as a harmonic quintuplet. Using the oblique pu...
Preprint
Full-text available
We report the discovery of the third tidally tilted pulsator, TIC 63328020. Observations with the TESS satellite reveal binary eclipses with an orbital period of 1.1057 d, and $\delta$ Scuti-type pulsations with a mode frequency of 21.09533 d$^{-1}$. This pulsation exhibits a septuplet of orbital sidelobes as well as a harmonic quintuplet. Using th...
Article
Eclipsing binary systems are unique stellar objects to examine and understand stellar evolution and formation. Thanks to these systems, the fundamental stellar parameters (mass, radius) can be obtained very precisely. The existence of metallic-line (Am) stars in binaries is noticeably common. However, the known number of Am stars in eclipsing binar...
Article
Full-text available
It has long been suspected that tidal forces in close binary stars could modify the orientation of the pulsation axis of the constituent stars. Such stars have been searched for, but until now never detected. Here we report the discovery of tidally trapped pulsations in the ellipsoidal variable HD 74423 in Transiting Exoplanet Survey Satellite (TES...
Article
Full-text available
In this study, a detailed spectroscopic analysis of 60 Tau is presented. 60 Tau is a Delta Scuti-type pulsating variable and it is also a metallic-lined (Am) star. The pulsation mechanism of Delta Scuti stars have been thought to be well understood and it was also suggested that metallic-lined stars did not exhibit pulsations. However, in recent st...
Article
CO Cam (TIC 160268882) is the second ‘single-sided pulsator’ to be discovered. These are stars where one hemisphere pulsates with a significantly higher amplitude than the other side of the star. CO Cam is a binary star comprised of an Am δ Sct primary star with T_(eff) = 7070 ± 150 K, and a spectroscopically undetected G main-sequence secondary st...
Preprint
Full-text available
Eclipsing binary systems are unique stellar objects to examine and understand the stellar evolution and the formation. Thanks to these systems, the fundamental stellar parameters (mass, radius) can be obtained very precisely. The existence of metallic-line (Am) stars in binaries is noticeably common. However, the known number of Am stars in eclipsi...
Article
Full-text available
Eclipsing binary systems are unique stellar objects to examine and understand the stellar evolution and the formation. Thanks to these systems, the fundamental stellar parameters (mass, radius) can be obtained very precisely. The existence of metallic-line (Am) stars in binaries is noticeably common. However, the known number of Am stars in eclipsi...
Article
If γ Dor-type pulsations are driven by the convective blocking mechanism, a convective envelope at a sufficient depth is essential. There are several hot γ Dor and hybrid star candidates in which there should not be an adequate convective envelope to excite the γ Dor-type oscillations. The existence of these hot objects needs an explanation. Theref...
Preprint
CO~Cam (TIC 160268882) is the second ``single-sided pulsator'' to be discovered. These are stars where one hemisphere pulsates with a significantly higher amplitude than the other side of the star. CO~Cam is a binary star comprised of an Am $\delta$~Sct primary star with $T_{\rm eff} = 7070 \pm 150$\,K, and a spectroscopically undetected G main-seq...
Preprint
Full-text available
It has long been suspected that tidal forces in close binary stars could modify the orientation of the pulsation axis of the constituent stars. Such stars have been searched for, but until now never detected. Here we report the discovery of tidally trapped pulsations in the ellipsoidal variable HD 74423 in TESS space photometry data. The system con...
Preprint
Full-text available
If Gamma Dor-type pulsations are driven by the convective blocking mechanism, a convective envelope at a sufficient depth is essential. There are several hot Gamma Dor and hybrid star candidates in which there should not be an adequate convective envelope to excite the{\gamma}Dor-type oscillations. The existence of these hot objects needs an explan...
Article
Full-text available
We present the first asteroseismic results for δ Scuti and γ Doradus stars observed in Sectors 1 and 2 of the TESS mission. We utilize the 2-min cadence TESS data for a sample of 117 stars to classify their behaviour regarding variability and place them in the Hertzsprung-Russell diagram using Gaia DR2 data. Included within our sample are the epony...
Preprint
Full-text available
We present the first asteroseismic results for $\delta$ Scuti and $\gamma$ Doradus stars observed in Sectors 1 and 2 of the TESS mission. We utilise the 2-min cadence TESS data for a sample of 117 stars to classify their behaviour regarding variability and place them in the Hertzsprung-Russell diagram using Gaia DR2 data. Included within our sample...
Preprint
Full-text available
Detached eclipsing binaries are remarkable systems to provide accurate fundamental stellar parameters. The fundamental stellar parameters and the metallicity values of stellar systems are needed to deeply understand the stellar evolution and formation. In this study, we focus on the detailed spectroscopic and photometric studies of three detached e...
Article
Full-text available
Detached eclipsing binaries are remarkable systems to provide accurate fundamental stellar parameters. The fundamental stellar parameters and the metallicity values of stellar systems are needed to deeply understand the stellar evolution and formation. In this study, we focus on the detailed spectroscopic and photometric studies of three detached e...
Preprint
Full-text available
We report an analysis of the first known Beta Cep pulsator observed by the TESS mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly-periodic pulsator, has at least 34 oscillation modes excited, 12 of those in the g-mode domain and 22 p modes. Analysis of archival data implies that the amplitude and frequency of the do...
Article
Full-text available
We report an analysis of the first known β Cep pulsator observed by the TESS mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly-period ic pulsator, has at least 34 oscillation modes excited, 12 of those in the g-mode domain and 22 p modes. Analysis of archival data implies that the amplitude and frequency of the domi...
Article
Full-text available
We present the time series analysis of GS UMa. GS UMa is a suspected δ Scuti variable with a primary frequency of 6.0987 d⁻¹.
Article
Full-text available
Eclipsing binary stars with a pulsating component are powerful tools that allow us to probe the stellar interior structure and the evolutionary statuses with a good accuracy. Therefore, in this study, spectroscopic and photometric examinations of an eclipsing binary system V948 Her are presented. The primary component of the system is classified to...
Article
Full-text available
In this study, the results of a research of low-metallicity pulsating stars are presented. The stars (-2.4<Fe/H<-0.5 dex) were selected from the LAMOST DR1 catalogue considering the ranges of 6500-8600 K, 3.8 - 4.5 of Teff and logg, respectively. Photometric data of the selected stars were taken from WASP. The stars showing light variation were det...
Article
Full-text available
We report the discovery of two massive eccentric systems with BRITE data, $\tau$ Ori and $\tau$ Lib, showing heartbeat effects close to the periastron passage. $\tau$ Lib exhibits shallow eclipses that will soon vanish due to the apsidal motion in the system. In neither system, tidally excited oscillations were detected.
Article
Full-text available
Although pulsations of $\delta$ Scuti type are not expected among Ap stars from a theoretical point of view, previous observations of the known $\delta$ Scuti star HD21190 indicated a spectral classification F2 III SrEuSi:, making it the most evolved Ap star known. Our atmospheric chemical analysis based on recent HARPS observations confirms the pr...
Article
Full-text available
\delta$ Scuti stars are remarkable objects for asteroseismology. In spite of decades of investigations, there are still important questions about these pulsating stars to be answered, such as their positions in $\log$$T_{\rm eff}$ $-$ $\log g$ diagram, or the dependence of the pulsation modes on atmospheric parameters and rotation. Therefore, we pe...
Article
Full-text available
Eclipsing binaries with a $\delta$ Sct component are powerful tools to derive the fundamental parameters and probe the internal structure of stars. In this study, spectral analysis of 6 primary $\delta$ Sct components in eclipsing binaries has been performed. Values of $T_{\rm eff}$, $v \sin i$, and metallicity for the stars have been derived from...
Conference Paper
Asteroseismology offers an opportunity for examination and detailed understanding of the internal structure of stars by probing their pulsating modes. To obtain reliable results by asteroseismology, accurate atmospheric parameters and metallicities of pulsating stars are required. Hence, in this study we carried out a spectroscopic survey of 8 sing...
Article
Full-text available
We present a spectroscopic survey of γ Doradus stars. The high-resolution, high signal-to-noise spectra of fifty-two objects were collected by five different spectrographs. The spectral classification, atmospheric parameters (Teff, log g, ξ), vsin i and chemical composition of the stars were derived. The spectral and luminosity classes of the stars...
Article
Full-text available
We present frequency analysis of the Kepler light curve of KIC 10486425, an eclipsing binary system with a pulsating component. The parameters of the binary were obtained by modelling the light curve with the Wilson-Devinney program. The residuals from this modelling were subject to Fourier analysis which allowed us to detect 120 periodic terms cha...
Article
In this work, we present the photometric study of A-type contact binaries V1073 Cyg and V357 Peg. The simultaneous solutions of BVR light and radial velocity curves of the systems are given. During the analysis of the light curves of V357 Peg, we have used two models included hot and dark spots. The third light contribution was also found for V357...
Article
In this work, we present the photometric study of A-type contact binaries V1073 Cyg and V357 Peg. The simultaneous solutions of BVR light and radial velocity curves of the systems are given. During the analysis of the light curves of V357 Peg, we have used two models included hot and dark spots. The third light contribution was also found for V357...
Article
It is accepted that the orbits of close binaries with solar type stars evolve through the angular momentum loss to form contact binaries and then they merge into fast rotating single stars. We present the story of single example of merging contact binary V1309 Sco which was observed in OGLE project before merging process in 2008. The analysis of th...
Article
It is accepted that the orbits of close binaries with solar type stars evolve through the angular momentum loss to form contact binaries and then they merge into fast rotating single stars. We present the story of single example of merging contact binary V1309 Sco which was observed in OGLE project before merging process in 2008. The analysis of th...
Article
Full-text available
It is accepted that the orbits of close binaries with solar type stars evolve through the angular momentum loss to form contact binaries and then they merge into fast rotating single stars. We present the story of single example of merging contact binary V1309 Sco which was observed in OGLE project before merging process in 2008. The analysis of th...
Conference Paper
Full-text available
zet: Bu çalışmada, Delta Scuti bileşenli Algol türü bir çift sistem V469 Cyg'nin literatürdeki ilk ışık ölçüm çalışması yer almaktadır. Wilson-Devinney programıyla, sistem ve bileşen parametreleri belirlenmiş ve kuramsal eğriler hesaplanmıştır. Kuramsal eğrilerden her bir gözlem noktasının farkı alınarak, zonklayan bileşenin zonklama doğası belirle...

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Projects (2)
Project
The known information about the interior stellar structure improves our knowledge of the stellar formation, evolution and hydrodynamic processes occurring in stars. The seismic waves of stars are the most important way to probe the interior stellar structure. Many stars in the Hertzsprung-Russell diagram exhibit variations with these seismic waves and they are known as pulsating variables. One of the most known groups of these pulsating stars is the DeltaScuti variables. The Delta Scuti stars show oscillation modes occurring in the upper and inner envelopes of a star. Bythe different pulsation modes and relatively larger pulsating amplitude of Delta Scuti variables, information about theinner layers of a star close to the stellar surface and the core can be obtained. The high-quality data of recent spacemissions show us that the previously known information about the pulsation stars, including Delta Scuti variables,has to be changed. The examinations of high-quality space photometry were showed that Delta Scuti type pulsationsmay take place outside of the Delta Scuti instability strip where the pulsations theoretically are not expected.Additionally, it was revealed that Delta Scuti stars present different pulsation characteristic than known from theground-based observations. These arisen problems related to the Delta Scuti variables show that the pulsationmechanism and the borders of the Delta Scuti instability strip should be re-investigated. To answer these problemssome detailed analyses would be performed and these analyses require precise fundamental (mass, radius) andatmospheric (effective temperature, metallicity) parameters. To accurately derive these fundamental stellarparameters, the only useful way is the analysis of the eclipsing binary systems. Therefore, in this project, we focus onthe detailed photometric and spectroscopic studies of the eclipsing binary systems with a Delta Scuti component toanswer the available questions associated with the Delta Scuti stars.
Project
Eclipsing binary stars are the only way to derive the fundamental stellar parameters (mass, radius) with a good accuracy. Especially, the eclipsing binary ones with a pulsation component offer us both examining the stellar structure via pulsation quantities and obtaining the accurate stellar parameters. To understand the stellar evolution and the interior structure, these variables are valuable tools. Hence, in this project, spectroscopic and photometric studies of eclipsing binaries with a possible pulsation component are taken into account. The aim of the project is determining the fundamental stellar and the fundamental atmospheric parameters of each component in selected binaries and investigating the interaction between two components and also between pulsation quantities and binarity.