The effect of turbulent mixing on the g‐mode spectrum of MS stars

Montalbán, J.; Miglio, A.; Eggenberger, P.; Noels, A.

doi:10.1002/asna.200710992

Cited by 12 publications

(12 citation statements)

References 26 publications

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“…Such an amplitude decline was detected for HD 50230 [12]. The difference in the hydrogen profiles that are formed in the zone of variable chemical composition if the two processes described above are considered separately is also reflected in the pulsation periods for low-order p and g modes [29]. However, precisely these modes were used to determine the parameter α for most stars from Table 1.…”

Section: Results Of the Computationsmentioning

confidence: 99%

Turbulent entrainment at the boundaries of the convective cores of main-sequence stars

Staritsin

2013

Astron. Rep.

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Abstract-Extra mixing of matter in stellar interiors at the boundaries of the convective cores of mainsequence stars is considered for the first time using the physical model of turbulent entrainment developed by Arnett and collaborators based on three-dimensional hydrodynamical simulations. The model takes into account the energy that goes into mixing the matter of the convective core and layers stable against convection located above the core. It is shown that the extent of the region of extra mixing expressed in units of the pressure scale height is not constant, and decreases as the star evolves along the main sequence. Adequate allowance for extra mixing at the boundaries of convective cores is necessary to clarify the relative importance of different mixing mechanisms in stellar interiors, as well as to determine stellar parameters using asteroseismlogy.

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Section: Results Of the Computationsmentioning

confidence: 99%

Turbulent entrainment at the boundaries of the convective cores of main-sequence stars

Staritsin

2013

Astron. Rep.

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“…The small separations are very useful for stellar modelling and need to be strongly constrained, e.g. Montalbán & Miglio (2006). The first two HARPS small-separation values were derived using l = 2 modes with only one frequency.…”

Section: Large and Small Separationsmentioning

confidence: 99%

“…parallax (Söderhjelm 1999) and, hence, luminosity, effective temperature, metallicity (Neuforge-Verheecke & Magain 1997), and radius (Kervella et al 2003), several models have been computed using these constraints (Thévenin et al 2002;Thoul et al 2003;Eggenberger et al 2004;Miglio & Montalbán 2005;Montalbán & Miglio 2006). However, it is difficult to find models that correctly account for all the observations simultaneously as stated in these publications.…”

Section: Introductionmentioning

confidence: 99%

Asteroseismology of $\mathsf{\alpha}$ Centauri A

Bazot

Bouchy²,

Kjeldsen³

et al. 2007

A&A

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Context. Asteroseismology provides a unique tool for studying stellar interiors. Recently p modes have been detected on the bright solar-like star α Cen A thanks to high-precision radial-velocity measurements. However, a better characterisation of these p modes is clearly needed to constrain theoretical models. Aims. We observed α Cen A during five nights using the HARPS spectrograph in order to improve our knowledge of the seismic properties of this star. Methods. We performed high-precision radial-velocity sequences and computed the acoustic spectrum of α Cen A. Results. We identify 34 p modes with angular degree l = 0−3 in the frequency range 1.8-2.9 mHz and amplitude range 13-48 cm s −1 , in agreement with previous seismic studies. We find an enhancement of the frequency scatter with the angular degree l that indicates, considering the high inclination axis of α Cen A, rotational splitting and explains the low values of previously suggested mode lifetimes. We also derive new values for the small separations that take the effect of rotational splitting into account. Conclusions. Our seismic study of α Cen A leads to a list of now well-identified p-mode frequencies and shows the importance of taking the rotation into account in order to properly characterise the p modes even in quite short campaigns.

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“…We refer to Montalbán et al (2008), these proceedings, for a more detailed description of this effect and for a quantitative estimation of the the turbulent mixing induced by rotation in models of typical β Cep stars.…”

Section: β Cephei and δ Scuti Starsmentioning

confidence: 99%

“…As an example we consider models of a 6 M star including, as extra mixing, turbulent diffusion near the core (described by a turbulent-diffusion coefficient D T = 5 × 10 3 cm 2 s −1 , see Montalbán et al 2008, these proceedings for a description of this simple parameterization). In Fig.…”

Section: High-order G Modesmentioning

confidence: 99%

Gravity modes and mixed modes as probes of stellar cores in main‐sequence stars: From solar‐like to β Cep stars

Miglio¹,

Montalbán

Eggenberger

et al. 2008

Astron Nachr

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We investigate how the frequencies of gravity modes depend on the detailed properties of the chemical composition gradient that develops near the core of main-sequence stars and, therefore, on the transport processes that are able to modify the µ profile in the central regions. We show that in main-sequence models, similarly to the case of white dwarfs, the periods of high-order gravity modes are accurately described by a uniform period spacing superposed to an oscillatory component. The periodicity and amplitude of such a component are related, respectively, to the location and sharpness of the µ gradient. We briefly discuss and interpret, by means of this simple approximation, the effect of turbulent mixing near the core on the periods of both high-order and low-order g modes, as well as of modes of mixed pressure-gravity character.

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The effect of turbulent mixing on the g‐mode spectrum of MS stars

Cited by 12 publications

References 26 publications

Turbulent entrainment at the boundaries of the convective cores of main-sequence stars

Turbulent entrainment at the boundaries of the convective cores of main-sequence stars

Asteroseismology of $\mathsf{\alpha}$ Centauri A

Gravity modes and mixed modes as probes of stellar cores in main‐sequence stars: From solar‐like to β Cep stars

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