Hyakutake spectroscopy suggests new class of comets

17 Jun 2002

Astronomers observing the close approach of Comet Hyakutake to the Earth in March discovered large quantities of the gases ethane and methane in the comet. This is the first time these or other molecules classified as "saturated hydrocarbons" have been found in a comet, strongly suggesting that at least two basic types of comets inhabit the Solar System.

Ethane has never before been detected in comets or in interstellar matter, the ultimate source material from which the Solar System was formed. Yet, comet investigators found levels of ethane in Comet Hyakutake that are about 1,000 times greater than can be explained if the molecules were formed by normal physical processes within the gases of the primordial solar nebula, the birth cloud of the Solar System.

The discoveries were made using a high-resolution infrared spectrometer at NASA's Infrared Telescope Facility atop Mauna Kea. The device was cooled to about minus 400 degrees Fahrenheit to achieve the needed sensitivity to infrared light.