Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager

Details Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager

Dec 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997aas...191.7311k&link_type=abstract

American Astronomical Society, 191st AAS Meeting, #73.11; Bulletin of the American Astronomical Society, Vol. 29, p.1322

Astronomy and Astrophysics

Astronomy

Scientific paper

The inference of the thermodynamic structure of the Sun from the observed properties of the solar normal modes of oscillation is a principal goal of helioseismology. We report the results of the first year of continuous observations of the Sun's internal structure using data from the Medium-l Program of the Michelson Doppler Imager (MDI) on board ESA/NASA spacecraft SOHO. The data provide continuous coverage of the acoustic (p) modes of angular degree l from 0 to 250, and the fundamental (f) mode of the Sun from l=100 to 250. During two 2-month intervals, the high-degree modes, up to l=1000, have been observed. The great stability of solar Dopplergrams measured by MDI permits detection of lower amplitude oscillations, extending the range and precision of measured normal mode frequencies, and thus substantially increasing the resolution and precision of helioseismic inversions. We present new inversion results for the radial and latitudinal seismic solar structures with particular attention to the transition region between the radiative and convection zones and to the energy-generating core. We discuss evidence for convective overshoot at the base of the convection zone, and the significance of deviations in the core structure from the standard evolutionary model. Comparing the f-mode frequencies with the corresponding frequencies of the standard solar models, we argue that the apparent photospheric solar radius (695.99 Mm) used to calibrate the models should be reduced by approximately 0.3 Mm. The discrepancy between the `seismic' and apparent photospheric radii is not explained by the known systematic errors in the helioseismic and photospheric measurements. If confirmed, this discrepancy represents a new interesting challenge to theories of solar convection and solar modeling. Using f-mode frequency splitting we estimate the large-scale structure of the subsurface magnetic fields. The variations of the solar oscillation frequencies during the first year of MDI observations are also discussed.

Affiliated with

Also associated with

No associations

Rating

Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Probing the Internal Structure of the Sun with the SOHO Michelson Doppler Imager will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1175232