Prospects for asteroseismology

Christensen‐Dalsgaard, J.; Houdek, G.

doi:10.1007/978-90-481-9198-7_7

Cited by 3 publications

(4 citation statements)

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“…The result is shown in Fig. 57, including also the similar analysis based on the AGSS09 composition (Christensen-Dalsgaard and Houdek 2010); at the base of the convection zone the required increase is around 30% when AGS05 is used, while AGSS09 requires an opacity increase of up to around 23%. The effects of the latter increase on the results of sound-speed inversion and model structure are shown in Fig.…”

Section: Possible Corrections To the Solar Modelsmentioning

confidence: 76%

“…It was pointed out, however, by Magic et al (2010) that favouring GS98 on this basis depended critically on other assumptions in the modelling. Including, for example, diffusion and settling (which was not taken into account by VandenBerg et al) the GS98 and AGS05 models were equally successful in reproducing the hook, while other aspects of the modelling similarly had substantial effects on the morphology of the isochrones; effects on the properties of convective cores of composition and other aspects of the model physics were also investigated by Christensen-Dalsgaard and Houdek (2010). Thus, although the details of the morphology is an interesting diagnostics of the model physics, it does not provide a definite constraint on any one feature such as the composition.…”

Section: Towards the Distant Starsmentioning

confidence: 99%

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Solar structure and evolution

Christensen‐Dalsgaard

2021

Living Rev Sol Phys

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The Sun provides a critical benchmark for the general study of stellar structure and evolution. Also, knowledge about the internal properties of the Sun is important for the understanding of solar atmospheric phenomena, including the solar magnetic cycle. Here I provide a brief overview of the theory of stellar structure and evolution, including the physical processes and parameters that are involved. This is followed by a discussion of solar evolution, extending from the birth to the latest stages. As a background for the interpretation of observations related to the solar interior I provide a rather extensive analysis of the sensitivity of solar models to the assumptions underlying their calculation. I then discuss the detailed information about the solar interior that has become available through helioseismic investigations and the detection of solar neutrinos, with further constraints provided by the observed abundances of the lightest elements. Revisions in the determination of the solar surface abundances have led to increased discrepancies, discussed in some detail, between the observational inferences and solar models. I finally briefly address the relation of the Sun to other similar stars and the prospects for asteroseismic investigations of stellar structure and evolution.

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Section: Possible Corrections To the Solar Modelsmentioning

confidence: 76%

Section: Towards the Distant Starsmentioning

confidence: 99%

Solar structure and evolution

Christensen‐Dalsgaard

2021

Living Rev Sol Phys

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“…To characterize a star based on high-order acoustic-mode frequencies one can in addition use the large frequency separation Δν nl = ν nl − ν n −1 l which essentially provides a measure of the mean density of the star. Thus the position of the star in a ( Δν , δν ) diagram, based on suitable averages, provides an indication of the mass and age of the star (Christensen-Dalsgaard 1984, 1988Ulrich 1986). Obviously, the calibration of the diagram depends on the physics and other parameters, such as the composition, of the stars (Gough 1987;Monteiro et al 2002, see also Lebreton & Montalbán, these proceedings).…”

Section: Asteroseismic Age Determinationmentioning

confidence: 99%

The Sun as a fundamental calibrator of stellar evolution

Christensen‐Dalsgaard

2008

Proc. IAU

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Abstract. The Sun is unique amongst stars in having a precisely determined age which does not depend on the modelling of stellar evolution. Furthermore, other global properties of the Sun are known to much higher accuracy than for any other star. Also, helioseismology has provided detailed determination of the solar internal structure and rotation. As a result, the Sun plays a central role in the development and test of stellar modelling. Here I discuss solar modelling and its application to tests of asteroseismic techniques for stellar age determination.

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“…The Kepler mission, successfully launched in March 7, 2009 (Borucki et al 2009), will also contribute to this field by observing stars on very long runs (4 years). The quality of the first data on stars showing solar-like oscillations (Bedding et al 2010a;Chaplin et al 2010;Hekker et al 2010b;Stello et al 2010) promises the asteroseismology a bright future on the study of stellar interiors and dynamical processes (Christensen-Dalsgaard & Houdek 2009;Samadi 2009;Mathis 2009).…”

Section: Introductionmentioning

confidence: 99%

The solar-like CoRoT target HD 170987: spectroscopic and seismic observations

Mathur

García²,

Catala

et al. 2010

A&A

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Context. The CoRoT mission is in its third year of observation and the data from the second long run in the galactic centre direction are being analysed. The solar-like oscillating stars that have been observed up to now have given some interesting results, specially concerning the amplitudes that are lower than predicted. We present here the results from the analysis of the star HD 170987. Aims. The goal of this research work is to characterise the global parameters of HD 170987. We look for global seismic parameters such as the mean large separation, maximum amplitude of the modes, and surface rotation because the signal-to-noise ratio in the observations does not allow us to measure individual modes. We also aim to retrieve the parameters of the star and its chemical composition.Methods. We studied the chemical composition of the star through ground-based observations performed with the NARVAL spectrograph. We used several methods to calculate the global parameters from the acoustic oscillations based on CoRoT data. The light curve of the star has been interpolated with inpainting algorithms to reduce the effect of data gaps. Results. We found the power excess related to p modes in the range [400-1200] μHz with a mean large separation of 55.2 ± 0.8 μHz with a probability above 95 % that increases to 55.9 ± 0.2 μHz in a higher frequency range μHz and a rejection level of 1%. A hint of the variation of this quantity with frequency was also found. The rotation period of the star is estimated to be around 4.3 days with an inclination axis of i = 50 • +20 −13 . We measured a bolometric amplitude per radial mode in a range [2.4-2.9] ppm around 1000 μHz. Finally we estimate the stellar mass with a grid of models, M = 1.43 ± 0.05 M , the radius, R = 1.96 ± 0.046 R , and the age ∼2.4 Gyr.

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Prospects for asteroseismology

Cited by 3 publications

References 100 publications

Solar structure and evolution

Solar structure and evolution

The Sun as a fundamental calibrator of stellar evolution

The solar-like CoRoT target HD 170987: spectroscopic and seismic observations

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