Process of Producing Cyanogen Gas in Comet Hale

March 28, 1997

COLUMBUS, Ohio -- Astronomers from Ohio State University and Lowell Observatory have confirmed the existence of cyanogen gas in Comet Hale-Bopp while the comet was still beyond the orbit of Jupiter, giving new evidence supporting one of two proposed theories explaining just how the gas is produced.

The conclusions, published this month in the journal Science, offer important new information about what mechanisms control the evolution of comets and whether the same processes are at work regardless of how close to or far from the sun the comet may be.

Comet Hale-Bopp was discovered by two astronomers July 23, 1995, and is now prominent in early evening and morning skies.

R. Mark Wagner, a research scientist with Ohio States astronomy department but based in Arizona, and David G. Schleicher, an astronomer at Lowell Observatory in Flagstaff, Az., made a set of observations of Comet Hale-Bopp in October, 1995, using the 4.5-meter Multiple Mirror Telescope. They took

detailed spectrographs of the comet through its head, or coma.

Wagner and Schleicher were looking for the telltale signs of cyanogen gas in the comets spectra. Cyanogen is a molecule composed of one atom each of carbon and nitrogen and a prominent compound found in most comets. As a comet gets closer to the sun, it releases more and more cyanogen.

What researchers did not know was the mechanism causing the release of cyanogen in the comet. Some experts believe that the gas is primarily liberated from dust particles in the icy body of the comet. Others suggest that the breaking apart of larger molecules in the comet -- hydrogen cyanide, for example -- is the primary source of the cyanogen.

"Our results suggest that even when the comet is far from the sun, the mechanism for the creation of cyanogen is the same at much closer distances," Wagner said. "Cyanogen cannot be released from the grains at slow speeds."

Scientists had once thought that cyanogen gas was released only after a comet had entered the H20 sublimation zone, a point on the comets orbit where it was about 3.0 astronomical units (AUs) -- about 280 million miles -- from the sun. (An AU is the distance between the sun and the earth.) "Thats where we saw it taking place when we observed Halleys Comet several years ago," Wagner said. But Wagner and Schleicher made their observations when Hale-Bopp was much farther away, 6.5 astronomical units (AUs) -- about 604 million miles -- from the sun. They were able to measure the spatial distribution of cyanogen gas throughout the comet, as well as its spectral profile.

"Its clear that this process takes place even further away from the sun. Sublimation or evaporation at much greater distances may be driven by things other than water -- carbon dioxide or carbon monoxide, for example.

"The distribution of cyanogen within Hale-Bopp at 6.5 AUs was similar to that of other comets at much closer distances to the sun," Wagner said. "That suggests the gas is formed through the same mechanism regardless of its distance from the sun."

Ohio State University

Related Comet Articles from Brightsurf:

Comet Chury's ultraviolet aurora
On Earth, auroras, also called northern lights, have always fascinated people.

Hubble snaps close-up of comet NEOWISE
The NASA/ESA Hubble Space Telescope has captured the closest images yet of the sky's latest visitor to make the headlines, comet C/2020 F3 NEOWISE, after it passed by the Sun.

Hubble snaps close-up of celebrity comet NEOWISE
The Hubble Space Telescope has snapped the closest images yet of the sky's latest visitor to make headlines, comet NEOWISE, after it passed by the Sun.

New comet discovered by ESA and NASA solar observatory
In late May and early June, Earthlings may be able to glimpse Comet SWAN.

Hubble captures breakup of comet ATLAS
The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS).

The salt of the comet
Under the leadership of astrophysicist Kathrin Altwegg, Bernese researchers have found an explanation for why very little nitrogen could previously be accounted for in the nebulous covering of comets: the building block for life predominantly occurs in the form of ammonium salts, the occurrence of which could not previously be measured.

New NASA image provides more details about first observed interstellar comet
A new image from NASA's Hubble Space Telescope provides important new details about the first interstellar comet astronomers have seen in our solar system.

Interstellar comet 2I -- Borisov swings past sun
Comet 2I/Borisov is a mysterious visitor from the depths of space -- the first identified comet to arrive here from another star.

Hubble observes 1st confirmed interstellar comet
Hubble has given astronomers their best look yet at an interstellar visitor -- comet 2I/Borisov -- whose speed and trajectory indicate it has come from beyond our solar system.

Interstellar Comet with a Familiar Look
A new comet discovered by amateur astronomer Gennady Borisov is an outcast from another star system, yet its properties determined so far are surprisingly familiar -- a new study led by JU researchers shows.

Read More: Comet News and Comet Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to