YREC: the Yale rotating stellar evolution code

Demarque, P.; Guenther, D. B.; Li, L. H.; Mazumdar, A.; Straka, Christian

doi:10.1007/978-1-4020-9440-8_4

Cited by 33 publications

(39 citation statements)

References 44 publications

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“…We computed such a representative 1.5 M model using the Yale Stellar Evolution Code (YREC; Demarque et al 2008;Guenther et al 1992). The model was selected to approximately reproduce the observed radial modes and true dipole period spacing of KIC 5006817, where we note that no "exact" match is necessary as the mode eigenfunctions (and therefore the rotational kernels) of similar models are almost identical (see also Deheuvels et al 2012).…”

Section: Testing Of the Rotational Profile From Forward Modellingmentioning

confidence: 99%

Pulsating red giant stars in eccentric binary systems discovered fromKeplerspace-based photometry

Beck

Hambleton

Vos

et al. 2014

A&A

135

151

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Context. The unparalleled photometric data obtained by NASA's Kepler Space Telescope has led to improved understanding of red giant stars and binary stars. Seismology allows us to constrain the properties of red giants. In addition to eclipsing binaries, eccentric non-eclipsing binaries that exhibit ellipsoidal modulations have been detected with Kepler. Aims. We aim to study the properties of eccentric binary systems containing a red giant star and to derive the parameters of the primary giant component. Methods. We applied asteroseismic techniques to determine the masses and radii of the primary component of each system. For a selected target, light and radial velocity curve modelling techniques were applied to extract the parameters of the system and its primary component. Stellar evolution and its effects on the evolution of the binary system were studied from theoretical models. Results. The paper presents the asteroseismic analysis of 18 pulsating red giants in eccentric binary systems, for which masses and radii were constrained. The orbital periods of these systems range from 20 to 440 days. The results of our ongoing radial velocity monitoring programme with the Hermes spectrograph reveal an eccentricity range of e = 0.2 to 0.76. As a case study we present a detailed analysis of KIC 5006817, whose rich oscillation spectrum allows for detailed seismic analysis. From seismology we constrain the rotational period of the envelope to be at least 165 d, which is roughly twice the orbital period. The stellar core rotates 13 times faster than the surface. From the spectrum and radial velocities we expect that the Doppler beaming signal should have a maximum amplitude of 300 ppm in the light curve. Fixing the mass and radius to the asteroseismically determined values, we find from our binary modelling a value of the gravity darkening exponent that is significantly larger than expected. Through binary modelling, we determine the mass of the secondary component to be 0.29 ± 0.03 M . Conclusions. For KIC 5006817 we exclude pseudo-synchronous rotation of the red giant with the orbit. The comparison of the results from seismology and modelling of the light curve shows a possible alignment of the rotational and orbital axis at the 2σ level. Red giant eccentric systems could be progenitors of cataclysmic variables and hot subdwarf B stars.

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Section: Testing Of the Rotational Profile From Forward Modellingmentioning

confidence: 99%

Pulsating red giant stars in eccentric binary systems discovered fromKeplerspace-based photometry

Beck

Hambleton

Vos

et al. 2014

A&A

135

151

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“…The model grid was constructed using the YREC stellar evolution code (Demarque et al 2008). Solar metallicity (Z = 0.02) models between 1.00 and 5.00 M , in increments of 0.01 M , were used.…”

Section: Asteroseismic Modelingmentioning

confidence: 99%

“…Pre-and post-main sequence evolutionary tracks (dashed and solid lines) were taken from D. Guenther (private comm.) using the YREC evolution code (Demarque et al 2008) with physics described in Guenther et al (2009). The borders of the classical δ Scuti instability strip (i.e., the general blue edge, BE, and the empirical red edge, RE emp , thick solid lines) are from Breger & Pamyatnykh (1998).…”

Section: Evolutionary Stage Of Hd 261711mentioning

confidence: 99%

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Regular frequency patterns in the youngδScuti star HD 261711 observed by the CoRoT and MOST satellites

Zwintz¹,

Fossati²,

Guenther³

et al. 2013

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Context. The internal structure of pre-main-sequence (PMS) stars is poorly constrained at present. This could change significantly through high-quality asteroseismological observations of a sample of such stars. Aims. We concentrate on an asteroseismological study of HD 261711, a rather hot δ Scuti-type pulsating member of the young open cluster NGC 2264 located at the blue border of the instability region. HD 261711 was discovered to be a PMS δ Scuti star using the time series photometry obtained by the MOST satellite in 2006. Methods. High-precision, time-series photometry of HD 261711 was obtained by the MOST and CoRoT satellites in four separate new observing runs that are put into context with the star's fundamental atmospheric parameters obtained from spectroscopy. Frequency Analysis was performed using Period04. The spectral analysis was performed using equivalent widths and spectral synthesis. Results. With the new MOST data set from 2011/12 and the two CoRoT light curves from 2008 and 2011/12, the δ Scuti variability was confirmed and regular groups of frequencies were discovered. The two pulsation frequencies identified in the data from the first MOST observing run in 2006 are confirmed and 23 new δ Scuti-type frequencies were discovered using the CoRoT data. Weighted average frequencies for each group were determined and are related to l = 0 and l = 1 p-modes. Evidence for amplitude modulation of the frequencies in two groups is seen. The effective temperature (T eff ) was derived to be 8600 ± 200 K, log g is 4.1 ± 0.2, and the projected rotational velocity (υ sin i) is 53 ± 1 km s −1 . Using our T eff value and the radius of 1.8 ± 0.5 R derived from spectral energy distribution (SED) fitting, we get a luminosity log L/L of 1.20 ± 0.14 which agrees well to the seismologically determined values of 1.65 R and, hence, a log L/L of 1.13. The radial velocity of 14 ± 2 km s −1 we derived for HD 261711, confirms the star's membership to NGC 2264. Conclusions. Our asteroseismic models suggest that HD 261711 is a δ Scuti-type star close to the zero-age main sequence (ZAMS) with a mass of 1.8 to 1.9 M . With an age of about 10 million years derived from asteroseismology, the star is either a young ZAMS star or a late PMS star just before the onset of hydrogen-core burning. The observed splittings about the l = 0 and 1 parent modes may be an artifact of the Fourier derived spectrum of frequencies with varying amplitudes. Reduced spectra are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via

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“…It has become clear since the time series data became available that the KIC T eff are not always accurate on a star-to-star basis (Molenda-Żakowicz et al 2010a,b;Lehmann et al 2011). T eff were, therefore, re-calculated by Pinsonneault & An (2012) using SLOAN photometry and the YREC models Demarque et al 2008), and cross-checking the results using the infra-red flux method calibration based on 2MASS photometry (Casagrande et al 2010). The T eff and uncertainties are listed in Table 3 with the heading "P/A".…”

Section: Photometrically Derived Atmospheric Parametersmentioning

confidence: 99%

Fundamental properties of fiveKeplerstars using global asteroseismic quantities and ground-based observations

Creevey

Doğan

Frasca

et al. 2012

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We present an asteroseismic study of the solar-like stars KIC 11395018, KIC 10273246, KIC 10920273, KIC 10339342, and KIC 11234888 using short-cadence time series of more than eight months from the Kepler satellite. For four of these stars, we derive atmospheric parameters from spectra acquired with the Nordic Optical Telescope. The global seismic quantities (average large frequency separation and frequency of maximum power), combined with the atmospheric parameters, yield the mean density and surface gravity with precisions of 2% and ∼0.03 dex, respectively. We also determine the radius, mass, and age with precisions of 2-5%, 7-11%, and ∼35%, respectively, using grid-based analyses. Coupling the stellar parameters with photometric data yields an asteroseismic distance with a precision better than 10%. A v sin i measurement provides a rotational period-inclination correlation, and using the rotational periods from the recent literature, we constrain the stellar inclination for three of the stars. An Li abundance analysis yields an independent estimate of the age, but this is inconsistent with the asteroseismically determined age for one of the stars. We assess the performance of five grid-based analysis methods and find them all to provide consistent values of the surface gravity to ∼0.03 dex when both atmospheric and seismic constraints are at hand. The different grid-based analyses all yield fitted values of radius and mass to within 2.4σ, and taking the mean of these results reduces it to 1.5σ. The absence of a metallicity constraint when the average large frequency separation is measured with a precision of 1% biases the fitted radius and mass for the stars with non-solar metallicity (metal-rich KIC 11395018 and metal-poor KIC 10273246), while including a metallicity constraint reduces the uncertainties in both of these parameters by almost a factor of two. We found that including the average small frequency separation improves the determination of the age only for KIC 11395018 and KIC 11234888, and for the latter this improvement was due to the lack of strong atmospheric constraints.

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YREC: the Yale rotating stellar evolution code

Cited by 33 publications

References 44 publications

Pulsating red giant stars in eccentric binary systems discovered fromKeplerspace-based photometry

Pulsating red giant stars in eccentric binary systems discovered fromKeplerspace-based photometry

Regular frequency patterns in the youngδScuti star HD 261711 observed by the CoRoT and MOST satellites

Fundamental properties of fiveKeplerstars using global asteroseismic quantities and ground-based observations

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