Contribution of Low-l P Modes to the Solar Equatorial Rotation Profile

Rabello Soares, M. C.; Roca-Cortés, T.; Jiménez, A.; Appourchaux, T.; Eff-Darwich, A.
Bibliographical reference

Astrophysical Journal v.480, p.840

Advertised on:
5
1997
Number of authors
5
IAC number of authors
2
Citations
5
Refereed citations
4
Description
The solar equatorial velocity profile is known down to the base of the convection zone with high precision (<=1%) from here downward until approximately 0.5 R&sun;, it seems to be constant, independent of latitude, and lower than the equatorial surface rate. This result comes from the inversion of high-l p-mode observations (Thompson et al. 1996), while low-l p modes, which penetrate deeper, are not measured to the precision required. Recently, new results from the LOWL instrument on such modes suggest that deeper down, the rotation rate could be even slower (Tomczyk, Schou, & Thompson 1995a). Here results from LOI-T, a low-resolution high-precision photometer, are presented and analyzed to yield accurate measurements of the frequencies and splittings of modes with 2 <= l <= 8. The accuracy of the frequency determinations and the agreement with the best results yielded by low- and high-l instruments give credit to the results and show its capability as an intercalibrating tool for experiment. The splittings found, combined with those of GONG (high-l modes), are used to perform an inversion of the equatorial rotation profile in the radiative interior; the result found is that the region from 0.2 <= r/R&sun; <= 0.4 rotates slower than the surface rate.
Type