Helioseismic calibration of the equation of state and chemical composition in the solar convective envelope

Vorontsov, S. V.; Батурин, В. А.; Ayukov, S. V.; Gryaznov, V. K.

doi:10.1093/mnras/sts701

Cited by 47 publications

(73 citation statements)

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“…We did not assume any mass loss, rotation, or core overshooting. However, we considered different chemical compositions following Castelli & Kurucz (2003) and Meszaros et al (2012) atmosphere models as well as recent helioseismic measurements of Y and Z made by Vorontsov et al (2013). The K-OPAL (K-OP) models mean that hybrid CK/OPAL (CK/OP) opacity data were used, viz., the Castelli & Kurucz or Meszaros et al data at outer layers (up to lg T ≈ 5.2) and the OPAL (OP) data at lg T > 5.2.…”

Section: Discussionmentioning

confidence: 99%

“…9 and 10. In the last case, we selected the mean values of Y and Z from the best-fit solution (Y = 0.25, Z = 0.008) obtained by Vorontsov et al (2013) for the SAHA-S3 EOS, using p-modes trapped in the upper half of the solar convective envelope, and (Y = 0.245, Z = 0.010) for p-modes trapped in deeper layers.…”

Section: Oscillation Spectra Of Early-type Starsmentioning

confidence: 99%

“…9 and 10, plotted in Fig. 6, illustrate how Asplund et al (2009) solar abundances of metals implemented with helioseismic measurements, of Y in Basu & Antia (2004), and Y and Z in Vorontsov et al (2013), change the oscillation spectra of unstable modes for models of early-type stars. Note that the OPAL models were stable for Z < 0.0108.…”

Section: The Op Modelsmentioning

confidence: 99%

“…Previously, the value of Z/X = 0.0245 was accepted following Grevesee & Noels (1993). Recently, Vorontsov et al (2013) obtained 0.008 < Z < 0.013 and 0.240 < Y < 0.255 from the reanalysis of the solar p-modes measurements. The results depend mainly on a particular version A&A 565, A76 (2014) of the EOS used.…”

Section: Introductionmentioning

confidence: 99%

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Seismic models of O and B stars with Kurucz’s opacity data

Cugier

2014

A&A

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Aims. We investigated seismic models of O and B stars calculated with the new Kurucz opacities implemented in the Opacity Project (OP) and Rogers & Iglesias OPAL opacity tables (OPAL). Methods. We studied the problem using Dziembowski's computer codes for linear, nonadiabatic, and nonradial oscillations. We considered seismic models of main sequence (MS) stars for different chemical compositions of elements in the mass-range 9 ≤ M ≤ 70 M . Results. The new opacity bump at lg T ≈ 5.06 that occurs in Kurucz's data influences evolutionary tracks mainly for M ≥ 30 M and markedly changes the driving zone for pulsations of stars in the whole mass range studied. We obtained no unstable oscillation modes for models corresponding to the abundance parameter Z ≤ 0.013 and only unstable low-frequency g-modes for 0.013 < Z ≤ 0.021. Conclusions. The opacity bump at lg T ≈ 5.3 should be significantly larger than the opacity bump at lg T ≈ 5.06 to drive pulsations of B stars in low-degree p-modes. Models with an increased OPAL (or OP) opacity bump at lg T ≈ 5.3 by a factor of about 1.7 have sufficiently large driving zones to excite modes in the β Cephei frequency-domain for 0.003 ≤ Z ≤ 0.021. These values of Z are in a good agreement with those derived spectroscopically for stars in the Galaxy and Magellanic Clouds.

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Section: Discussionmentioning

confidence: 99%

Section: Oscillation Spectra Of Early-type Starsmentioning

confidence: 99%

Section: The Op Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seismic models of O and B stars with Kurucz’s opacity data

Cugier

2014

A&A

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“…The proxy model, which may differ significantly from the target, is improved iteratively in linearised steps using an appropriate form of the variational principle, described in detail in Vorontsov et al (2013). In this iterative process, we address "seismic" models -the models which can be represented by two functions of radial coordinate, the representation which is sufficient for the normal-mode analysis.…”

Section: And References Thereinmentioning

confidence: 99%

A seismic and gravitationally bound double star observed byKepler

Appourchaux

Antia

Ball

et al. 2015

A&A

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Context. Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe stars using asteroseismology. Aims. The derivation of stellar parameters has usually been done with single stars. The aim of the paper is to derive the stellar parameters of a double-star system (HIP 93511), for which an interferometric orbit has been observed along with asteroseismic measurements. Methods. We used a time series of nearly two years of data for the double star to detect the two oscillation-mode envelopes that appear in the power spectrum. Using a new scaling relation based on luminosity, we derived the radius and mass of each star. We derived the age of each star using two proxies: one based upon the large frequency separation and a new one based upon the small frequency separation. Using stellar modelling, the mode frequencies allowed us to derive the radius, the mass, and the age of each component. In addition, speckle interferometry performed since 2006 has enabled us to recover the orbit of the system and the total mass of the system. Results. From the determination of the orbit, the total mass of the system is 2.34 +0.45 −0.33 M . The total seismic mass using scaling relations is 2.47 ± 0.07 M . The seismic age derived using the new proxy based upon the small frequency separation is 3.5 ± 0.3 Gyr. Based on stellar modelling, the mean common age of the system is 2.7-3.9 Gyr. The mean total seismic mass of the system is 2.34-2.53 M consistent with what we determined independently with the orbit. The stellar models provide the mean radius, mass, and age of the stars as R A = 1.82−1.87 R , M A = 1.25−1.39 M , Age A = 2.6-3.5 Gyr; R B = 1.22−1.25 R , M B = 1.08−1.14 M , Age B = 3.35-4.21 Gyr. The models provide two sets of values for Star A: [1.25-1.27] M and [1.34-1.39] M . We detect a convective core in Star A, while Star B does not have any. For the metallicity of the binary system of Z ≈ 0.02, we set the limit between stars having a convective core in the range [1.14-1.25] M .

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2020

Solar Neutrino Physics

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Helioseismic calibration of the equation of state and chemical composition in the solar convective envelope

Cited by 47 publications

References 28 publications

Seismic models of O and B stars with Kurucz’s opacity data

Seismic models of O and B stars with Kurucz’s opacity data

A seismic and gravitationally bound double star observed byKepler

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