Preparing the COROT space mission: Incidence   and characterisation of
pulsation in the lower instability strip

Poretti, E.; Garrido, R.; Amado, P. J.; Uytterhoeven, K.; Handler, G.; Alonso, R.; Martín, S.; Aerts, C.; Catala, C.; Goupil, M. J.; Michel, E.; Mantegazza, L.; Mathias, P.; Pretorius, Magaretha L.; Belmonte, JA; Claret, A.; Rodrı́guez, E.; Suárez, J. C.; Vuthela, F. F.; Weiß, W. W.; Ballereau, D.; Bouret, J. C.; Charpinet, S.; Hua, T.; Lüftinger, T.; Nesvacil, N.; Veer-Menneret, C. van't

doi:10.1051/0004-6361:20030711

Cited by 25 publications

(29 citation statements)

References 12 publications

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“…The δ Sct variability of HD 174966 was discovered in the preparatory work of the CoRoT mission (Poretti et al 2003). HD 174966 was observed in the same CoRoT frame as the other δ Sct-type star HD 174936 (GH09), during the first short run SRc01, between April 2007 and May 2007.…”

Section: Analysis Of the Light Curve Observed By Corotmentioning

confidence: 83%

An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy

Hernández

Moya

Michel

et al. 2013

A&A

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Aims. The aim of this work was to use a multi-approach technique to derive the most accurate values possible of the physical parameters of the δ Sct star HD 174966, which was observed with the CoRoT satellite. In addition, we searched for a periodic pattern in the frequency spectra with the goal of using it to determine the mean density of the star. Methods. First, we extracted the frequency content from the CoRoT light curve. Then, we derived the physical parameters of HD 174966 and carried a mode identification out from the spectroscopic and photometric observations. We used this information to look for the models fulfilling all the conditions and discussed the inaccuracies of the method because of the rotation effects. In a final step, we searched for patterns in the frequency set using a Fourier transform, discussed its origin, and studied the possibility of using the periodicity to obtain information about the physical parameters of the star. Results. A total of 185 peaks were obtained from the Fourier analysis of the CoRoT light curve, all of which were reliable pulsating frequencies. From the spectroscopic observations, 18 oscillation modes were detected and identified, and the inclination angle (62.5•+7.5 −17.5 ) and the rotational velocity of the star (142 km s −1 ) were estimated. From the multi-colour photometric observations, only three frequencies were detected that correspond to the main ones in the CoRoT light curve. We looked for periodicities within the 185 frequencies and found a quasiperiodic pattern Δν ∼ 64 μHz. Using the inclination angle, the rotational velocity, and an Echelle diagram (showing a double comb outside the asymptotic regime), we concluded that the periodicity corresponds to a large separation structure. The quasiperiodic pattern allowed us to discriminate models from a grid. As a result, the value of the mean density is achieved with a 6% uncertainty. So, the Δν pattern could be used as a new observable for A-F type stars.Key words. asteroseismology -stars: oscillations -stars: variables: delta Scuti -stars: interiors -stars: fundamental parametersstars: rotation The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes,

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Section: Analysis Of the Light Curve Observed By Corotmentioning

confidence: 83%

An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy

Hernández

Moya

Michel

et al. 2013

A&A

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“…They also estimated the age to be about 1.8 ± 0.2 Gyr. Poretti et al (2003) have measured v sin i 23 km s −1 . They also found that HD 175272 does not show any evident trace of variability.…”

Section: Introductionmentioning

confidence: 99%

Differential asteroseismic study of seismic twins observed by CoRoT

Ozel

Mosser

Dupret

et al. 2013

A&A

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Context. The CoRoT short asteroseismic runs give us the opportunity to observe a large variety of late-type stars through their solarlike oscillations. We report the observation and modeling of the F5V star HD 175272. Aims. Our aim is to define a method for extracting as much information as possible from a noisy oscillation spectrum. Methods. We followed a differential approach that consists of using a well-known star as a reference to characterize another star. We used classical tools such as the envelope autocorrelation function to derive the global seismic parameters of the star. We compared HD 175272 with HD 181420 through a linear approach, because they appear to be asteroseismic twins. Results. The comparison with the reference star enables us to substantially enhance the scientific output for HD 175272. First, we determined its global characteristics through a detailed seismic analysis of HD 181420. Second, with our differential approach, we measured the difference of mass, radius and age between HD 175272 and HD 181420. Conclusions. We have developed a general method able to derive asteroseismic constraints on a star even in case of low-quality data. This method can be applied to stars with interesting properties but low signal-to-noise ratio oscillation spectrum, such as stars hosting an exoplanet or members of a binary system.

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“…The percentage of pulsating stars compared to the total number of stars inside the instability strip is known as the incidence. The incidence of δ Sct in the MW, from the study of the Solar neighborhood and open clusters is somewhere between a quarter and half of the stars within the instability strip (Breger 2000;Poretti et al 2003;Balona & Dziembowski 2011), although the majority of these have very small amplitudes of a few milimagnitudes.…”

Section: Delta Scuti Starsmentioning

confidence: 99%

The Overlooked Role of Stellar Variability in the Extended Main Sequence of LMC Intermediate-Age Clusters

Salinas

Pajkos

Strader

et al. 2016

ApJL

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Intermediate-age star clusters in the Large Magellanic Cloud show extended main sequence turn offs (MSTOs), which are not consistent with a canonical single stellar population. These broad turn offs have been interpreted as evidence for extended star formation and/or stellar rotation. Since most of these studies use single frames per filter to do the photometry, the presence of variable stars near the MSTO in these clusters has remained unnoticed and their impact totally ignored. We model the influence of Delta Scuti using synthetic CMDs, adding variable stars following different levels of incidence and amplitude distributions. We show that Delta Scuti observed at a single phase will produce a broadening of the MSTO without affecting other areas of a CMD like the upper MS or the red clump; furthermore, the amount of spread introduced correlates with cluster age as observed. This broadening is constrained to ages ∼ 1-3 Gyr when the MSTO area crosses the instability strip, which is also consistent with observations. Variable stars cannot explain bifurcarted MSTOs or the extended MSTOs seen in some young clusters, but they can make an important contribution to the extended MSTOs in intermediate-age clusters.

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Preparing the COROT space mission: Incidence and characterisation of pulsation in the lower instability strip

Cited by 25 publications

References 12 publications

An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy

An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy

Differential asteroseismic study of seismic twins observed by CoRoT

The Overlooked Role of Stellar Variability in the Extended Main Sequence of LMC Intermediate-Age Clusters

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