On December 14, 2020, there was a total solar eclipse that could be seen in Chile and Argentina. Now scientists have revealed images of a tiny speck flying by the Sun as the event happened. That speck is a recently discovered comet known as C/2020 X3 (SOHO).
At left, images from the LASCO C2 camera on the ESA/NASA SOHO observatory show the C/2020 X3 (SOHO) comet in the bottom left-hand corner. And on the right is a composite image of the total solar eclipse on December 14, 2020. It's based on 65 frames taken by Andreas Möller (Arbeitskreis Meteore e.V.) in Piedras del Aguila, Argentina, and processed by Jay Pasachoff and Roman Vanur.
Amateur astronomer Worachate Boonplod first spotted the comet on December 13, 2020 while poring over satellite data during a citizen science project called Sungrazer, which is funded by NASA. Sungrazer seeks to recruit anyone who is interested to look for new comets in images that have been captured jointly by the European Space Agency (ESA) and the NASA Solar and Heliospheric Observatory (SOHO).
Boonplod knew that the eclipse was imminent, and wanted to know whether his comet discovery would show up as a tiny little speck moving in the outer atmosphere of the Sun in eclipse photographs.
The comet is thought to originate from a large parent comet that broke apart into smaller fragments more than a thousand years ago. These fragments are still orbiting the Sun today, and are known as Kreutz sungrazers because German astronomer Heinrich Kreutz was the first to show that they are related, and because their orbit takes them so close to the Sun.
Kreutz sungrazing comets are typically found in images from SOHO, whose camera functions by mimicking total solar eclipses; the overwhelming brightness of the Sun is blocked by a solid occulting disk to reveal dimmer features in the outer atmosphere and other celestial objects including comets. So far, researchers have discovered 4,108 comets in SOHO images,. The one spotted by Boonplod is the 3,524th Kreutz sungrazer.
When this image was taken, the comet was estimated to be traveling at about 450,000 miles per hour, roughly 2.7 million miles away from the surface of the Sun. The comet's diameter is only about 50 feet, and it disintegrated due to the intensity of solar radiation.