NASA's Spitzer observes gas emission from comet ISON

Jul 24, 2013
These images from NASA's Spitzer Space Telescope of C/2012 S1 (Comet ISON) were taken on June 13, when ISON was 310 million miles (about 500 million kilometers) from the sun.Credit: NASA/JPL-Caltech/JHUAPL/UCF

Astronomers using NASA's Spitzer Space Telescope have observed what most likely are strong carbon dioxide emissions from Comet ISON ahead of its anticipated pass through the inner solar system later this year.

Images captured June 13 with Spitzer's Infrared Array Camera indicate carbon dioxide is slowly and steadily "fizzing" away from the so-called "soda-pop ," along with dust, in a tail about 186,400 miles (300,000 kilometers) long.

"We estimate ISON is emitting about 2.2 million pounds (1 million kilograms) of what is most likely and about 120 million pounds (54.4 million kilograms) of dust every day," said Carey Lisse, leader of NASA's Comet ISON Observation Campaign and a senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Previous observations made by NASA's Hubble Space Telescope and the Swift Gamma-Ray Burst Mission and Deep Impact spacecraft gave us only upper limits for any gas emission from ISON. Thanks to Spitzer, we now know for sure the comet's distant activity has been powered by gas."

Comet ISON was about 312 million miles (502 million kilometers) from the sun, 3.35 times farther than Earth, when the observations were made.

"These fabulous observations of ISON are unique and set the stage for more observations and discoveries to follow as part of a comprehensive NASA campaign to observe the comet," said James L. Green, NASA's director of planetary science in Washington. "ISON is very exciting. We believe that data collected from this comet can help explain how and when the solar system first formed."

Comet ISON (officially known as C/2012 S1) is less than 3 miles (4.8 kilometers) in diameter, about the size of a small mountain, and weighs between 7 billion and 7 trillion pounds (3.2 billion and 3.2 trillion kilograms). Because the comet is still very far away, its true size and density have not been determined accurately. Like all comets, ISON is a dirty snowball made up of dust and frozen gases such as water, ammonia, methane and carbon dioxide. These are some of the fundamental building blocks, which scientists believe led to the formation of the planets 4.5 billion years ago.

Comet ISON is believed to be inbound on its first passage from the distant Oort Cloud, a roughly spherical collection of comets and comet-like structures that exists in a space between one-tenth light-year and 1 light-year from the sun. The comet will pass within 724,000 miles (1.16 million kilometers) of the sun on Nov. 28.

It is warming up gradually as it gets closer to the sun. In the process, different gases are heating up to the point of evaporation, revealing themselves to instruments in space and on the ground. Carbon dioxide is thought to be the gas that powers emission for most comets between the orbits of Saturn and the asteroids.

The comet was discovered Sept. 21, roughly between Jupiter and Saturn, by Vitali Nevski and Artyom Novichonok at the International Scientific Optical Network (ISON) near Kislovodsk, Russia. This counts as an early detection of a comet, and the strong may have made the detection possible.

"This observation gives us a good picture of part of the composition of ISON, and, by extension, of the proto-planetary disk from which the planets were formed," said Lisse. "Much of the carbon in the comet appears to be locked up in ice. We will know even more in late July and August, when the comet begins to warm up near the water-ice line outside of the orbit of Mars, and we can detect the most abundant frozen gas, which is water, as it boils away from the comet."

Explore further: JUICE mission gets green light for next stage of development

add to favorites email to friend print save as pdf

Related Stories

Hubble brings faraway comet into view

Apr 23, 2013

(Phys.org) —The NASA Hubble Space Telescope has given astronomers their clearest view yet of Comet ISON, a newly-discovered sun grazer comet that may light up the sky later this year, or come so close to ...

A new view of comet ISON

May 03, 2013

Here's a new image of Comet C/2012 S1 ISON, as seen on May 1, 2013 by Ernesto Guido and Nick Howes of the Remanzacco Observatory. They used the 2 meter La Palma Telescope. Their initial approximation of the ...

Comet ISON brings holiday fireworks (w/ Video)

Jul 02, 2013

This July Fourth the solar system is showing off some fireworks of its own. Superficially resembling a skyrocket, comet ISON is hurtling toward the sun presently at a whopping 48,000 mph.

Comet ISON shaping up to be a spectacular display

Jan 15, 2013

(Phys.org)—Excitement is mounting for astronomers and star gazers the world over as word spreads that Comet ISON may go down in the history books as one of the flashiest ever. First discovered in September ...

Recommended for you

Bad weather delays Japan asteroid probe lift off

5 hours ago

Bad weather will delay the launch of a Japanese space probe on a six-year mission to mine a distant asteroid, just weeks after a European spacecraft's historic landing on a comet captivated the world.

Manchester scientists boost NASA's missions to Mars

14 hours ago

Computer Scientists from The University of Manchester have boosted NASA space missions by pioneering a global project to develop programs that efficiently test and control NASA spacecraft.

ESA image: The gold standard

14 hours ago

The Eutelsat-9B satellite with its EDRS-A payload is shown in the anechoic test chamber of Airbus Defence and Space in Toulouse, France, having completed its final antenna pattern tests today.

Frost-covered chaos on Mars

14 hours ago

Thanks to a break in the dusty 'weather' over the giant Hellas Basin at the beginning of this year, ESA's Mars Express was able to look down into the seven kilometre-deep basin and onto the frosty surface ...

Rosetta's comet: In the shadow of the coma

21 hours ago

This NAVCAM mosaic comprises four individual images taken on 20 November from a distance of 30.8 km from the centre of Comet 67P/C-G. The image resolution is 2.6 m/pixel, so each original 1024 x 1024 pixel ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.