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X-ray flare sparks quake inside Sun

Kosovichev, A. G.; Zharkova, V. V.

Solar flares involve a release of the Sun's magnetic energy as X-radiation, particle beams and high-speed plasma flows. But we have discovered, using data from the Solar and Heliospheric Observatory (SOHO), that these flares also affect the Sun's interior, generating seismic waves similar to earthquakes. For example, a three-kilometre-high seismic…

Large-scale coronal heating by the small-scale magnetic field of the Sun

Schrijver, C. J.; Tarbell, T. D.; Shine, R. A. +6 more

Magnetic fields play a crucial role in heating the outer atmospheres of the Sun and Sun-like stars, but the mechanisms by which magnetic energy in the photosphere is converted to thermal energy in the corona remain unclear. Observations show that magnetic fields emerge onto the solar surface as bipolar regions with a broad range of length scales. …

The sun's shape and brightness

Kuhn, J. R.; Bush, R. I.; Scherrer, P. +1 more

We present satellite data that show that the sun's shape and temperature vary with latitude in an unexpectedly complex way. Although the solar oblateness shows no evidence of varying with the solar cycle, we find a significant hexadecapole shape term which may vary. We also see a variation of about 1.5 K in the surface temperature with latitude. B…

Long-lived giant cells detected at the surface of the Sun

Scherrer, P. H.; Duvall, T. L.; Beck, J. G.

Giant convective cells have been predicted to exist in the Sun. Such cells should span the entire zone unstable to convective motions - now known to cover the outer 29 per cent of the Sun's radius - and could be dredging up the magnetic flux that is thought to be the source of solar activity (sunspots). Several studies have failed to detect these …