Long-term photometric monitoring with the Mercator telescope

Cuypers, J.; Aerts, C.; Cat, P. De; Goossens, K.; Schoenaers, C.; Uytterhoeven, K.; Acke, B.; Davignon, G.; Debosscher, J.; Decin, L.; Meester, W. De; Deroo, P.; Drummond, R.; Kolenberg, K.; Lefever, K.; Raskin, Gert; Reyniers, M.; Saesen, S.; Vandenbussche, B.; Malderen, Roeland Van; Verhoelst, Tijl; Winckel, H. Van; Waelkens, Christoffel

doi:10.1051/0004-6361/200911691

Cited by 36 publications

(25 citation statements)

References 36 publications

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“…The authors reported a frequency at 1.61 d −1 to be an = 5(±1) and m = 4(±1) and the frequency at 1.25 d −1 -which is f 1 of Henry et al (2005) -to be an = 4(±1) and m = 3(±1) mode. Cuypers et al (2009) confirmed the presence of the previously identified pulsation frequencies using photometric time series in the Geneva system. In the literature, 43 Cygni is reported to have an effective temperature, T eff , of 7300 ± 250 K and a log g of 4.35 ± 0.14 cms −2 (David & Hillenbrand 2015); its projected rotational velocity, υ sin i, was determined to be 44 km s −1 (e.g., Fekel et al 2003).…”

Section: Introductionsupporting

confidence: 87%

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

Zwintz

Reeth

Tkachenko

et al. 2017

A&A

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Context. Photometric time series of the γ Doradus star 43 Cyg obtained with the BRITE-Constellation nano-satellites allow us to study its pulsational properties in detail and to constrain its interior structure. Aims. We aim to find a g-mode period spacing pattern that allows us to determine the near-core rotation rate of 43 Cyg and redetermine the star's fundamental atmospheric parameters and chemical composition.Methods. We conducted a frequency analysis using the 156-days long data set obtained with the BRITE-Toronto satellite and employed a suite of MESA/GYRE models to derive the mode identification, asymptotic period spacing and near-core rotation rate. We also used high-resolution, high signal-to-noise ratio spectroscopic data obtained at the 1.2m Mercator telescope with the HER-MES spectrograph to redetermine the fundamental atmospheric parameters and chemical composition of 43 Cyg using the software Spectroscopy Made Easy (SME). Results. We detected 43 intrinsic pulsation frequencies and identified 18 of them to be part of a period spacing pattern consisting of prograde dipole modes with an asymptotic period spacing ∆Π l=1 of 2970 +700 −570 s. The near-core rotation rate was determined to be f rot = 0.56 +0.12 −0.14 d −1 . The atmosphere of 43 Cyg shows solar chemical composition at an effective temperature, T eff , of 7150 ± 150 K, a log g of 4.2 ± 0.6 dex and a projected rotational velocity, υ sin i, of 44 ± 4 km s −1 . Conclusions. The morphology of the observed period spacing patterns shows indications of the presence of a significant chemical gradient in the stellar interior.

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Section: Introductionsupporting

confidence: 87%

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

Zwintz

Reeth

Tkachenko

et al. 2017

A&A

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“…Their typical pulsation periods are found to be in the range of 0.02d to 0.25 d (Breger 2000). γ Doradus stars locate in the sim-ilar position in the instability strip as the δ Scuti stars but with relatively larger pulsating periods ranging from 0.3 d to 3 d (Cuypers et al 2009). RR Lyrae stars are radially pulsating giant stars with spectral type A to F with periods from ∼ 0.2 to ∼1 d (Smith 2004).…”

Section: Pulsating Variable Starsmentioning

confidence: 93%

Variable Stars Observed in the Galactic Disk by AST3-1 from Dome A, Antarctica

Wang

et al. 2017

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AST3-1 is the second-generation wide-field optical photometric telescope dedicated to time domain astronomy at Dome A, Antarctica. Here we present the results of i band images survey from AST3-1 towards one Galactic disk field. Based on time-series photometry of 92,583 stars, 560 variable stars were detected with i magnitude ≤ 16.5 mag during eight days of observations; 339 of these are previously unknown variables. We tentatively classify the 560 variables as 285 eclipsing binaries (EW, EB, EA), 27 pulsating variable stars (δ Scuti, γ Doradus, δ Cephei variable and RR Lyrae stars) and 248 other types of variables (unclassified periodic, multi-periodic and aperiodic variable stars). Among the eclipsing binaries, 34 show O'Connell effects. One of the aperiodic variables shows a plateau light curve and another one shows a secondary maximum after peak brightness. We also detected a complex binary system with RS CVn-like light curve morphology; this object is being followed-up spectroscopically using the Gemini South telescope.

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“…Handler 1999;Kaye et al 1999;Cuypers et al 2009), space-based observations revealed dozens to hundreds of oscillation frequencies for each star. This in principle should allow the detection of period spacing patterns.…”

Section: The Methodologymentioning

confidence: 99%

Detecting non-uniform period spacings in theKeplerphotometry ofγDoradus stars: methodology and case studies

Reeth

Tkachenko

Aerts

et al. 2015

A&A

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Context. The analysis of stellar oscillations is one of the most reliable ways to probe stellar interiors. Recent space missions such as Kepler have provided us with an opportunity to study these oscillations with unprecedented detail. For many multi-periodic pulsators such as γ Doradus stars, this led to the detection of dozens to hundreds of oscillation frequencies that could not be found from groundbased observations. Aims. We aim to detect non-uniform period spacings in the Fourier spectra of a sample of γ Doradus stars observed by Kepler. Such detection is complicated by both the large number of significant frequencies in the space photometry and by overlapping nonequidistant rotationally split multiplets. Methods. Guided by theoretical properties of gravity-mode oscillation of γ Doradus stars, we developed a period-spacing detection method and applied it to Kepler observations of a few stars, after having tested the performance from simulations. Results. The application of the technique resulted in the clear detection of non-uniform period spacing series for three out of the five treated Kepler targets. Disadvantages of the technique are also discussed, and include the disability to distinguish between different values of the spherical degree and azimuthal order of the oscillation modes without additional theoretical modelling. Conclusions. Despite the shortcomings, the method is shown to allow solid detections of period spacings for γ Doradus stars, which will allow future asteroseismic analyses of these stars.

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Long-term photometric monitoring with the Mercator telescope

Cited by 36 publications

References 36 publications

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

Variable Stars Observed in the Galactic Disk by AST3-1 from Dome A, Antarctica

Detecting non-uniform period spacings in theKeplerphotometry ofγDoradus stars: methodology and case studies

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