Tag Archives: hartley 2

Primordial Dry Ice Fuels Comet Jets

*Initial science results on comet released from University of Maryland, much more to come UMD scientists say.* 


Jets Galore. This enhanced image, one of the closest taken of comet Hartley 2. Image credit: University of Maryland

COLLEGE PARK, Md. – One of the biggest comet findings coming out of the amazing images and data taken by the University of Maryland-ledEPOXI mission as it zipped past comet Hartley 2 last week is that dry ice is the ‘jet’ fuel for this comet and perhaps many others. 

Images from the flyby show spectacular jets of gas and particles bursting from many distinct spots on the surface of the comet. This is the first time images of a comet have been sharp enough to allow scientists to link jets of dust and gas with specific surface features. Analysis of the spectral signatures of the materials coming from the jets shows primarily CO2 gas (carbon dioxide) and particles of dust and ice. 

“Previously it was thought that water vapor from water ice was the propulsive force behind jets of material coming off of the body, or nucleus, of the comet,” said University of Maryland Astronomy Professor Jessica Sunshine, who is deputy principal investigator for the EPOXI mission. “We now have unambiguous evidence that solar heating of subsurface frozen carbon dioxide (dry ice), directly to a gas, a process known as sublimation, is powering the many jets of material coming from the comet. This is a finding that only could have been made by traveling to a comet, because ground based telescopes can’t detect CO2 and current space telescopes aren’t tuned to look for this gas,” Sunshine said.  (more…)

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UMD-Led Team Begins Imaging Comet Hartley 2 with Deep Impact Spacecraft

COLLEGE PARK, Md. — Some five years after its July 4th 2005 ‘comet shot’ was seen around the world, the Deep Impact spacecraft has begun regular imaging of a second comet target, Hartley 2. The spacecraft will continue imaging Hartley 2 during and after its closest approach on November 4, providing an extended look at the comet. However, there won’t be any fireworks this time as Deep Impact’s probe craft was destroyed in its deliberate 2005 collision with comet Tempel 1.


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