The largest solar telescope on Earth got the sharpest view of a sunspot.
Vaguely resembling a sunflower – or Sauron’s Eye of The Lord of the Rings – the spot appears as a dark spot crowned by plasma ribbons that have been sculpted by magnetic fields that have sprung from the center of the spot. With approximately 15,000 kilometers in diameter, the whole place could comfortably engulf the Earth with free space.
The image was captured last January by the new Daniel K. Inouye solar telescope in Maui, Hawaii, observatory director Thomas Rimmele and colleagues reported in the December 4 Solar Physics. With its 4 meter wide mirror, the telescope begins to offer the highest views of our everlasting star (SN: 29/1/20). The ability to see details up to 20 kilometers wide can help researchers in the wake of enduring mysteries about the sun (SN: 21/08/20), such as why its outer atmosphere is millions of degrees warmer than its surface .
Sunspots mark where beams of magnetic fields pierce the surface of the sun. Magnetic fields suppress the hot gas that boiled from below, which cools the surface and makes it look darker than its surroundings. While the average surface temperature is about 5,500 ° Celsius, the core of a sunspot can be “only” 3,700 ° C.
The image was taken as part of a test for the nearly completed telescope, which should open for business sometime in 2021. Although the observatory targets late spring or early summer, says Claire Raftery, director of communications for the Solar Observatory. National Boulder, Colorado, the ongoing COVID-19 pandemic may delay opening.