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Rare Carbon-Monoxide Comet Turns Blue in Stunning Deep-Space Photos

Comet C/2016 R2 (PANSTARRS)
Astrophotographer Chris Schur captured this view of the comet C/2016 R2 (PANSTARRS) on Jan. 17, 2018. (Image credit: Chris Schur/<a href=""></a>)

A rare carbon-monoxide comet turns deep blue as it whizzes through the inner solar system in a series of images by astrophotographer Chris Schur.

Named C/2016 R2 (PANSTARRS), or R2 for short, this comet is unusually rich with ionized carbon monoxide, which glows increasingly blue as it gets closer to the sun. "That is the gas carbon monoxide making its appearance," Schur told in an email.

Its tail of dust will also continue to grow as the comet encounters increasing levels of solar radiation along the way. "The constantly contorting tail is a superb photographic target," Schur said. Schur's photos of R2 reveal a fuzzy-looking comet that appears teal at first and gradually turns blue as the tail becomes more elongated. [Best Close Encounters of the Comet Kind]

Comet C/2016 R2 (PANSTARRS) on Jan. 5, 2018. (Image credit: Chris Schur/

Comet R2 was discovered in 2016 by astronomers using the Pan-STARRS telescope in Haleakalā, Hawaii. It was closest to Earth on Dec. 23, 2017, when it was a safe distance away: roughly 191 million miles (307 million kilometers). 

The comet will make its closest approach to the sun on May 9, 2018. If it doesn't burn up and disintegrate as it swoops around the sun, the comet will then start making its way back toward the icy outer region of the solar system known as the Oort Cloud

Comet C/2016 R2 (PANSTARRS) on Jan. 12, 2018. (Image credit: Chris Schur/

Assuming that the comet survives its trip around the sun this time, C/2016 R2 will swing by Earth and the sun again — but not for another 20,228 years, according to NASA's small-body database

To capture these images of the comet, Schur used a 10-inch Orion astrograph reflector telescope with an ST-10XME self-guiding CCD camera. 

Email Hanneke Weitering at or follow her @hannekescience. Follow us @Spacedotcom, Facebook and Google+. Original article on

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Hanneke Weitering

SPACE.COM ASSOCIATE EDITOR — Hanneke joined the team at in August 2016 as a staff writer and producer. She has previously written for Scholastic, MedPage Today, Scienceline and Oak Ridge National Lab. After studying physics at the University of Tennessee in her home town of Knoxville, she earned her graduate degree in Science, Health and Environmental Reporting (SHERP) from New York University.