<i>δ</i>Scuti stars in Praesepe

Frandsen, S.; Pigulski, A.; Nuspl, J.; Breger, M.; Belmonte, Juan Antonio; Dall, T. H.; Arentoft, T.; Sterken, C.; Medupe, T.; Gupta, S. K.; Pinheiro, F. J. G.; Monteiro, M. J. P. F. G.; Barban, C.; Chevreton, M.; Michel, E.; Benkő, J. M.; Barcza, Sz.; Szabo, Robert M.; Kolaczkowski, Z.; Kopacki, G.; Udovichenko, S. N.

doi:10.1051/0004-6361:20010950

Cited by 10 publications

(10 citation statements)

References 8 publications

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“…12 we compare these values for f 1 with theoretical predictions (Garrido et al 1990;Garrido 2000). Model atmospheres were calculated assuming Pop I, T eff = 7400 K, log g = 3.96 (Hintz et al 1998) and α = 1.25.…”

Section: Colour Photometrymentioning

confidence: 79%

“…We prewhitened the light curves for the 7 significant frequencies and calculated statistical weights, following Frandsen et al (2001), from the residuals, to see if applying such weights could improve the noise levels. We also tried to decorrelate SAAO data residuals for effects of seeing, sky-background levels and relative position on the CCD chip, using the methods described by Frandsen et al (1996, or see Arentoft et al 2001.…”

Section: The Campaign Datamentioning

confidence: 99%

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V 1162 Ori: A multiperiodicδScuti star with variable period and amplitude

Arentoft¹,

Sterken²,

Handler

et al. 2001

A&A

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Abstract. We present the results of multisite observations of the δ Scuti star V 1162 Ori. The observations were done in the period October 1999 -May 2000, when 18 telescopes at 15 observatories were used to collect 253 light extrema during a total of 290 hours of time-series observations. The purpose of the observations was to investigate amplitude and period variability previously observed in this star, and to search for low-amplitude frequencies. We detect, apart from the main frequency and its two first harmonics, four additional frequencies in the light curves, all with low amplitudes (1-3 mmag). Combining the present data set with data obtained in 1998-99 at ESO confirms the new frequencies and reveals the probable presence of yet another pulsational frequency. All five low-amplitude frequencies are statistically significant in the data, but at least one of them (f5) suffers from uncertainty due to aliasing. Using colour photometry we find evidence for a radial main frequency (f1), while most or all low-amplitude frequencies are likely non-radial. We show that the main frequency of V 1162 Ori has variable amplitude and period/phase, the latter is also displayed in the O-C diagram from light extrema. The amplitude variability in our data is cyclic with a period of 282 d and a range of nearly 20 mmag, but earlier amplitude values quoted in the literature cannot be explained by this cyclic variation. O-C analysis including data from the literature show that the period of V 1162 Ori displays a linear period change as well as sudden or cyclic variations on a time scale similar to that of the amplitude variations.

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Section: Colour Photometrymentioning

confidence: 79%

Section: The Campaign Datamentioning

confidence: 99%

V 1162 Ori: A multiperiodicδScuti star with variable period and amplitude

Arentoft¹,

Sterken²,

Handler

et al. 2001

A&A

Self Cite

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“…As a starting point it is nevertheless a good assumption to try to fit the radial-velocity data of ξ Hya by such a set of functions, as the lifetimes are expected to exceed the length of the observing run (Houdek & Gough 2002). We have performed an iterative fit using different methods, among which Period98 (Sperl 1998) and a procedure by Frandsen et al (2001). An oscillation with a S /N above 4 is detected at 9 frequencies.…”

Section: Time-series Analysismentioning

confidence: 99%

Detection of Solar-like oscillations in the G7 giant star ξ Hya

Frandsen

Carrier²,

Aerts

et al. 2002

A&A

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Abstract. We report the firm discovery of solar-like oscillations in a giant star. We monitored the star ξ Hya (G7III) continuously during one month with the CORALIE spectrograph attached to the 1.2 m Swiss Euler telescope. The 433 high-precision radial-velocity measurements clearly reveal multiple oscillation frequencies in the range 50-130 µHz, corresponding to periods between 2.0 and 5.5 hours. The amplitudes of the strongest modes are slightly smaller than 2 m s −1 . Current model calculations are compatible with the detected modes.

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“…Four of these stars, BW Cnc, BS Cnc, BU Cnc and BN Cnc (HD 73798, HD 73450, HD 73576 and HD 73763, respectively), were observed by several campaigns of the STEPHI network (Michel et al 1995). The fifth star, BV Cnc (HD 73746), was observed by Frandsen et al (2001). The observed frequencies of these stars are listed in Table 1.…”

Section: O B S E Rvat I O Na L Datamentioning

confidence: 97%

Mode stability in Scuti stars: linear analysis versus observations in open clusters

Suárez

Michel

Houdek

et al. 2007

Monthly Notices of the Royal Astronomical Society

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A comparison between linear‐stability analysis and observations of pulsation modes in five δ Scuti stars, belonging to the same cluster, is presented. The study is based on a work by Michel et al., in which such a comparison was performed for a representative set of model solutions obtained independently for each individual star considered. In this paper, we revisit that work by Michel et al. following, however, a new approach which consists of the search for a single, complete, and coherent solution for all the selected stars, in order to constrain and test the assumed physics describing these objects. To do so, refined descriptions for the effects of rotation on the determination of the global stellar parameters and on the adiabatic oscillation frequency computations are used. In addition, a crude attempt is made to study the role of rotation on the prediction of mode instabilities. The present results are found to be comparable with those reported by Michel et al. Within the temperature range log Teff= 3.87 –3.88, agreement between observations and model computations of unstable modes is restricted to values for the mixing‐length parameter αNL≃ 1.50. This indicates that for these stars a smaller value for αNL is required than that suggested from a calibrated solar model. We stress the point that the linear‐stability analysis used in this work still assumes stellar models without rotation and that further developments are required for a proper description of the interaction between rotation and pulsation dynamics.

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δScuti stars in Praesepe

Cited by 10 publications

References 8 publications

V 1162 Ori: A multiperiodicδScuti star with variable period and amplitude

V 1162 Ori: A multiperiodicδScuti star with variable period and amplitude

Detection of Solar-like oscillations in the G7 giant star ξ Hya

Mode stability in Scuti stars: linear analysis versus observations in open clusters

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