Comet Trailing Behind ISON Explodes

Almost 450 million km from Earth, Comet C/2012 X1 (LINEAR) has exploded. 

Amateur astronomers are reporting a 100-fold increase in the comet's brightness compared to predictions, and the comet's atmosphere or "coma" now resembles that of exploding Comet 17P/Holmes in 2007.



Below you can see the magnitude graph of C/2012 X1


Using a remotely-controlled 0.5 meter telescope in New Mexico, European observers Ernesto Guido, Martino Nicolini and Nick Howes took the picture of the spherical explosion on Oct 21st:

"The predicted magnitude of the comet on Oct. 20th was about +14," says Guido. 

"Now it is close to +8.5." This is below the threshold for naked-eye visibility, but bright enough for backyard telescopes equipped with digital cameras.

Prompted by the reports of Guido et al, Romanian amateur astronomer Maximilian Teodorescu observed the comet on Oct. 22nd, confirming its brightness and spherical structure. 

"It looked exactly like Comet Holmes back in 2007," says Teodorescu.

Located in the constellation Coma Berenices, Comet LINEAR X1 rises in the east about an hour before the sun. The low altitude of the comet in morning twilight is a challenge. 

"I could not see the comet through the eyepiece of my 4.5 inch refracting telescope," adds Teodorescu, "but the camera detected it easily enough."

The outburst does not necessarily signal a disintegration of the comet. Possibly, a local vein or cavern of deep ice in the comet's nucleus has been exposed to sunlight. 

Rapid evaporation of fragile ices could account for the comet's bigger- and brighter-than-expected atmosphere. Monitoring in the nights ahead might reveal clues to what happened ... and when.



(Thanks to Ernesto Guido, Nick Howes and Martino Nicolini)