Astronomers Spot a Comet Giving Birth

A digital filter helped scientists witness Comet Holmes unleashing a cluster of baby comets

Scientists recently spotted a swarm of baby comets flying away from a passing parent comet — the largest comet birth ever witnessed. The discovery was assisted by a special digital filter that enhances faint features within the cloud of comet debris.

Comet 17P/Holmes first gained attention in 2007 with an outburst that brightened by a million times in less than a day, and threw off a dust cloud that grew larger than the sun in the eyes of Earth telescopes. But a team of researchers from the University of California, Los Angeles and the University of Hawaii focused on small fragments that seemed to detach from the comet nucleus.

“Initially we thought this comet was unique simply because of the scale of the outburst,” said Stevenson. “But we soon realized that the aftermath of the outburst showed unusual features, such as these fast-moving fragments, that have not been detected around other comets.”

The astronomers took images over nine nights in November 2007 at the Canada-France-Hawaii Telescope in Hawaii. Their special weapon was a Laplacian filter that sharply enhances discontinuities within images.

That allowed the team to spot many small objects zipping away at speeds up to 280 mph. The brightness of the objects revealed them as baby comets creating their own dust clouds as surface ice vaporized and transformed directly into gas.

Astronomers remain puzzled over the exact cause of cometary outbursts. Some speculate that internal pressure builds up when sub-surface ice evaporates as comets move closer to the sun, and eventually leads to the pressure outburst that spews out a cloud of dust and gas.

More oohing and aahing should ensue at the European Planetary Science Congress in Potsdam, Germany, where more findings on the comet babies are being presented today. Comet Holmes should return for another photo op when it makes its closest approach to the sun in 2014, after a six-year journey.