Commentary Relative to the Seismic Structure of the Sun: Internal Rotation, Oblateness, and Solar Shape

Helioseismological studies have the ability to yield tremendous insight with respect to the internal structure and shape of the solar body. Such observations indicate that while the convection zone displays differential rotation, the core rotates as a rigid body. The latter is located below the tachocline layer, where powerful shear stresses are believed to occur. Beyond simple oblateness, seismological studies indicate that the Sun displays significant higher order shape terms (quadrupole, hexadecapole) which may, or may not, vary with the solar cycle. In this work, such seismological findings are briefly discussed with the intent of highlighting that 1) the differential rotation of the convection zone, 2) the rigid body rotation of the core, 3) the presence of the tachocline layer and 4) the appearance of higher order shape terms, all lend support to the idea that the solar body is composed of material in the condensed state. In this regard, the existence of the tachocline layer in the solar interior and the solid body rotation of the core constitute the nineteenth and twentieth lines of evidence that the Sun is condensed matter.