THE SPIRAL CORE OF COMET 12P: Around the world, astronomers are monitoring Comet 12P/Pons-Brooks as it approaches the sun for a close encounter in April. Most cameras are focused on the comet's magnificent tail, which is growing longer every night. Norwegian astronomer Jan Erik Vallestad decided instead to take a closer look at the comet's core--and there he found a spiral:
"The image has been processed in Pixinsight with moderate stretching to reveal structure in the core," explains Vallestad. "This is doable because the core itself was not 'blown out' (saturated) in my original data." Other astronomers have also noticed the spiral or "yin-yang shape" of the comet's core; it appears to be real.
Juris Seņņikovs of Dobele, Latvia, is a believer. Last night he photographed the comet and found the spiral, too:
"After seeing today's front-page image from Jan Erik Vallestad, I processed my image of Comet 12P/Pons-Brooks in a similar way," says Seņņikovs. "Much to my surprise, I also got a spiral around the comet's core. Without processing one can easily miss this structure."
Why spiral? Take a look at the comet's lightcurve. Some astronomers believe that 12P's frequent outbursts are a sign of "cryovolcanism." According to this idea, the comet's surface is peppered with geysers, which spew icy plumes of dust and gas into space when fragile vents are exposed to sunlight. Such exhaust plumes would naturally bend themselves into spirals as the comet rotates.
Comet 12P is currently located in the western sky after sunset, about 15 degrees above the horizon for most observers. Shining as brightly as a 6th magnitude star, the comet has been posing alongside the Andromeda Nebula for beauty shots all month long. Point your telescope here and take a look!
