Featured Research

from universities, journals, and other organizations

Cassini VIMS Team Finds That Phoebe May Be Kin To Comets

Date:
June 24, 2004
Source:
University Of Arizona
Summary:
Scientists may at last have settled the debate on the origin of Saturn's moon, Phoebe. Saturn long ago captured its largest outermost satellite, Phoebe, when the moon wandered in from the frigid region beyond the orbit of Neptune called the Kuiper belt, they conclude.

Cassini's Visual and Infrared Mapping Spectrometer detected water, carbon dioxide, minerals -- and unidentified material in Phoebe's surface on the June 11 flyby. The composite image above shows infrared reflectance (top left), false color (top middle), carbon dioxide indicated in red (top right), unidentified material indicated in green (lower left), and a mineral map (lower right) where ferrous iron is shown as red, green as unidentified material, and blue as water ice.
Credit: Photo : NASA/Cassini VIMS

Scientists may at last have settled the debate on the origin of Saturn's moon, Phoebe.

Saturn long ago captured its largest outermost satellite, Phoebe, when the moon wandered in from the frigid region beyond the orbit of Neptune called the Kuiper belt, they conclude.

The scientists analyzed results from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) taken during the June 11 Cassini spacecraft's Phoebe flyby. They announced the results today at a news conference at the NASA Jet Propulsion Laboratory in Pasadena, Calif.

Scientists have long doubted that Phoebe came from the same disk of material that formed Saturn and most of its moons. Phoebe has an unusual orbit that is inclined to Saturn's equator, revolves backward with respect to both Saturn's rotation and orbital motion, and travels in the opposite direction of Saturn's other satellites.

Phoebe is widely believed to have wandered past Saturn and been captured by that planet's mighty gravitational field. Where it wandered from was the question.

"All our evidence leads us to conclude that Phoebe's surface is made of water ice, water-bearing minerals, carbon dioxide, possible clays and primitive organic chemicals in different locations on the surface," VIMS team member Roger N. Clark of the U.S. Geological Survey in Denver said a few days after the flyby. "We also see spectral signatures of materials that we have not yet identified."

It is clear that the materials in Phoebe's surface bear little resemblance to the predominantly rocky material found in asteroids in the belt between Mars and Jupiter. The materials that make up Phoebe formed farther out in the solar system, where it is cold enough for them to remain stable.

"One intriguing result of the VIMS measurements is the discovery of possible chemical similarities between the materials on Phoebe and those seen on comets," said VIMS team leader Robert H. Brown of the University of Arizona.

Short period comets are thought to sit among other primitive solar system debris in the Kuiper belt, until tugged by Neptune's gravity toward the inner solar system.

Evidence that Phoebe might be chemically kin to comets strengthens the case that it's similar to Kuiper Belt Objects.

The VIMS instrument is an imaging spectrometer that produces a special data set called an image cube. It takes an image of an object in many colors simultaneously. An ordinary video camera takes images in three primary colors (red, green, and blue) and combines them to produce images as seen by the human eye. The VIMS instrument takes images in 352 separate colors, spanning a realm of colors far beyond those visible to humans. All materials reflect light in a unique way. So molecules of any element or compound can be identified by the colors they reflect or absorb, their "signature" spectra. The VIMS team knew the basic chemical make-up of Phoebe only a few days after flyby.

That Phoebe likely comes from the Kuiper belt and not from the Mars-Jupiter asteroid belt is another "first" for the Cassini mission, Brown noted. Cassini has become the first spacecraft to flyby a Kuiper belt object, he said.

Cassini flew by Phoebe on June 11. Cassini will conduct a critical 96-minute main-engine burn before going into orbit around Saturn on June 30 (July 1 Universal Time). During Cassini's planned four-year tour it will conduct 76 orbits around the Saturn system and execute 52 close encounters with seven of Saturn's 31 known moons.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The VIMS team is based at the University of Arizona in Tucson.


Story Source:

The above story is based on materials provided by University Of Arizona. Note: Materials may be edited for content and length.


Cite This Page:

University Of Arizona. "Cassini VIMS Team Finds That Phoebe May Be Kin To Comets." ScienceDaily. ScienceDaily, 24 June 2004. <www.sciencedaily.com/releases/2004/06/040624093746.htm>.
University Of Arizona. (2004, June 24). Cassini VIMS Team Finds That Phoebe May Be Kin To Comets. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2004/06/040624093746.htm
University Of Arizona. "Cassini VIMS Team Finds That Phoebe May Be Kin To Comets." ScienceDaily. www.sciencedaily.com/releases/2004/06/040624093746.htm (accessed April 20, 2014).

Share This



More Space & Time News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Easter Morning Delivery for Space Station

Raw: Easter Morning Delivery for Space Station

AP (Apr. 20, 2014) Space station astronauts got a special Easter treat: a cargo ship full of supplies. The SpaceX company's cargo ship, Dragon, spent two days chasing the International Space Station following its launch from Cape Canaveral. (April 20) Video provided by AP
Powered by NewsLook.com
A Hoax? Cosmetics Company Wants To Brighten The Moon

A Hoax? Cosmetics Company Wants To Brighten The Moon

Newsy (Apr. 19, 2014) FOREO, a Swedish cosmetics company, says it wants to brighten the moon to lower electricity costs. Video provided by Newsy
Powered by NewsLook.com
Raw: Space X Launches to Space Station

Raw: Space X Launches to Space Station

AP (Apr. 18, 2014) On it's second attempt this week, The Space X company launched Friday from Cape Canaveral to ferry supplies to the International Space Station. (April 18) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins