The ESA/NASA Solar and Heliospheric Observatory (SOHO) detected its 4,000th comet on June 15, 2020.
SOHO-4000 is seen here in an image from the SOHO alongside its 3,999th comet discovery. The two comets are relatively close at approximately 1 million miles apart, suggesting that they could have been connected together as recently as a few years ago. Image credit: ESA / NASA / SOHO / Karl Battams.
The newly-discovered comet, nicknamed SOHO-4000, belongs to the Kreutz family of sungrazers.
These comets all follow the same general trajectory, one that carries them skimming through the outer atmosphere of the Sun.
SOHO-4000 has diameter between 4.5 and 9 m (15-30 feet) and was extremely faint and close to the Sun when discovered.
“Not only has SOHO rewritten the history books in terms of solar physics, but, unexpectedly, it’s rewritten the books in terms of comets as well,” said SOHO project member Dr. Karl Battams, a scientist at the U.S. Naval Research Lab.
SOHO-4000 was originally spotted in the SOHO data by citizen scientist Trygve Prestgard.
“I feel very fortunate to have found SOHO’s 4,000th comet,” Prestgard said.
“Although I knew that SOHO was nearing its 4,000th comet discovery, I did not initially think that this sungrazer would be it.”
“It was only after discussing with other SOHO comet hunters, and counting through the most recent sungrazer discoveries, that the idea sunk in. I am honored to be part of such an amazing collaborative effort.”
Prestgard is searching for comets in his free time with the Sungrazer Project, a NASA-funded citizen science project, managed by Dr. Battams, which grew out of comet discoveries by citizen scientists early into SOHO’s mission.
“I have been actively involved in the Sungrazer Project for about eight years. My work with sungrazers is what solidified my long-term interest in planetary science,” said Prestgard, who recently completed a master’s degree in geophysics from Université Grenoble Alpes.
“I enjoy the feeling of discovering something previously unknown, whether this is a nice ‘real time’ comet or a ‘long-gone’ overlooked one in the archives.”
