Seismic detection of acoustic sharp features in the CoRoT target HD 49933

@article{Mazumdar2012SeismicDO,
  title={Seismic detection of acoustic sharp features in the CoRoT target HD 49933},
  author={Anwesh Mazumdar and Eric Michel and H. M. Antia and S{\'e}bastien Deheuvels},
  journal={Astronomy and Astrophysics},
  year={2012},
  volume={540}
}
ABSTRACT The technique of determining the acoustic location of layers of sharp changes in the sound speed inside a star from the oscillatorysignal in its frequencies is applied on a solar-type star, the CoRoT target, HD 49933. We are able to determine the acoustic depth ofthe second helium ionisation zone of HD 49933 to be 794 +55 68 s. The acoustic depth of the base of the convective zone is found to be1855 +173 412 s where the large error bars reflect the ambiguity in the result, which is di… Expand

Figures and Tables from this paper

The CoRoT target HD 49933: a possible seismic signature of heavy elements ionization in the deep convective zone
We use a seismic diagnostic, based on the derivative of the phase shift of the reflected by the surface acoustic waves, to probe the outer layers of the star HD 49933. This diagnostic is particularlyExpand
Measurement of Acoustic Glitches in Solar-type Stars from Oscillation Frequencies Observed by Kepler
For the very best and brightest asteroseismic solar-type targets observed by Kepler, the frequency precision is sufficient to determine the acoustic depths of the surface convective layer and theExpand
Seismic Measurement of the Locations of the Base of Convection Zone and Helium Ionization Zone for Stars in the Kepler Seismic LEGACY Sample
Acoustic glitches are regions inside a star where the sound speed or its derivatives change abruptly. These leave a small characteristic oscillatory signature in the stellar oscillation frequencies.Expand
A Theoretical Study of Acoustic Glitches in Low-Mass Main-Sequence Stars
There are regions in stars, such as ionization zones and the interface between radiative and convective regions, that cause a localized sharp variation in the sound speed. These are known asExpand
Acoustic glitches in solar-type stars from Kepler
We report the measurement of the acoustic locations of layers of sharp variation in sound speed in the interiors of 19 solar-type stars observed by the Kepler mission. The oscillatory signal in theExpand
On the possibility of using seismic probes to study the core composition in pulsating white dwarfs
White dwarfs correspond to the final stages of stellar evolution of solar-type stars. In these objects, production of energy by nuclear burning has ended which means that a white dwarf simply coolsExpand
Prospects for asteroseismic inference on the envelope helium abundance in red giant stars
Regions of rapid variation in the internal structure of a star are often referred to as acoustic glitches since they create a characteristic periodic signature in the frequencies of p modes. Here weExpand
Grid-based seismic modelling at high and low signal-to-noise ratios. HD 181420 and HD 175272
Context. Recently, the CoRoT target HD 175272 (F5V), which shows a weak signal of solar-like oscillations, was modelled by a differential asteroseismic analysis (Ozel et al. 2013, A&A, 558, A79)Expand
Diagnostics from Solar and Stellar Glitches
Sudden changes in the internal structure of stars, placed at the interface between convective and radiative regions, regions of partial ionisation, or between layers that have acquired differentExpand
High-precision acoustic helium signatures in 18 low-mass low-luminosity red giants - Analysis from more than four years of Kepler observations
Context. High-precision frequencies of acoustic modes in red giant stars are now available thanks to the long observing length and high quality of the light curves provided by the NASA KeplerExpand
...
1
2
3
...

References

SHOWING 1-10 OF 14 REFERENCES
Seismic extraction of the convective extent in solar-like stars The observational point of view
Convection is the first manifestation of macroscopic motions in stars. In the next decade, the extent of the external convective zone of solar-like stars will have to be derived from theExpand
Seismic study of stellar convective regions: the base of the convective envelope in low-mass stars
ABSTRA C T The possibility of observing solar-type oscillations on other stars is of great relevance to investigating the uncertain aspects of the internal structure of stars. One of these aspects isExpand
Evidence for a sharp structure variation inside a red-giant star
Context. The availability of precisely determined frequencies of radial and non-radial oscillation modes in red giants is finally paving the way for detailed studies of the internal structure ofExpand
An asteroseismic signature of helium ionization
We investigate the influence of the ionization of helium on the low-degree acoustic oscillation frequencies in model solar-type stars. The signature in the oscillation frequencies characterizing the.Expand
Seismic study of stellar convective cores
It has been shown that a discontinuity in the derivatives of the sound speed at the edge of the convective regions inside a star gives rise to a characteristic oscillatory signal in the frequenciesExpand
A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry
Context. Solar-like oscillations have now been observed in several stars, thanks to ground-based spectroscopic observations and space-borne photometry. CoRoT, which has been in orbit since DecemberExpand
Asteroseismic determination of helium abundance in stellar envelopes
ABSTRACT Intermediate degree modes of the solar oscillations have previously been used to de-termine the solar helium abundance to a high degree of precision. However, we cannotexpect to observe suchExpand
The ratio of small to large separations of acoustic oscillations as a diagnostic of the interior of solar-like stars
By considering stellar models with the same interior structure but different outer layers we demonstrate that the ratio of the small to large separations of acoustic oscillations in solar-like starsExpand
Asteroseismic diagrams for solar-type stars
We explore the feasibility of applying the Christensen-Dalsgaard diagram to real asteroseismic data and provide quantitative measures of the uncertainty associated with the results. We also propose aExpand
Helioseismic measurement of the extent of overshoot below the solar convection zone
The discontinuity in the derivatives of the sound speed at the base of the overshoot layer below the solar convection zone introduces a characteristic oscillatory component in the frequencies ofExpand
...
1
2
...