[新闻] 英天文学家利用“卡西尼”号发现新的土星环 [酷图]

　　英国天文学家9日宣布，他们在研究“卡西尼”号飞船拍摄的土星照片时，发现了土星环中存在一个发光微弱的新土星环。

　　最早发现这个土星环的是英国伦敦大学的卡尔·默里教授，他在当天举行的英国协会科学节上介绍说，这个土星环与土星的小卫星土卫十五的运行轨道接近，宽为306公里，处在已命名的土星环A环和F环之间。土星环是在伽利略发明了天文望远镜之后由他本人首次观测到的。土星环自里向外按D、C、B、A、F、G、E的顺序依次分布了7个环。

　　另外，默里和同事在对“卡西尼”号拍摄的F环照片进行分析时，发现F环以外620多公里的位置有一个直径大约为4公里的物体。他们目前无法判断该物体是否是固态，如果答案是肯定的，那么这个物体将成为土星的又一颗卫星。今年8月，法国科学家曾发现土星周围两颗类似的卫星，而此前天文学家计算到的土星卫星为33颗。

　　“卡西尼”号飞船经过7年的太空旅行，于今年7月1日成功飞入土星轨道。英国科学家设计并建造了“卡西尼”号上的6台仪器，它目前正利用自身携带的大量科学探测仪器对土星大气、光环和多颗卫星进行探测研究。（记者 曹丽君）

 
　　来源： 新华网  2004-09-10 13:17

Cassini Discovers Ring and One, Possibly Two, Objects at Saturn
September 09, 2004

Scientists examining Saturn's contorted F ring, which has baffled them since its discovery, have found one small body, possibly two, orbiting in the F ring region, and a ring of material associated with Saturn's moon Atlas.

A small object was discovered moving near the outside edge of the F ring, interior to the orbit of Saturn's moon Pandora. The object was seen by Dr. Carl Murray, imaging team member at Queen Mary, University of London, in images taken on June 21, 2004, just days before Cassini arrived at Saturn. "I noticed this barely detectable object skirting the outer part of the F ring. It was an incredible privilege to be the first person to spot it," he said. Murray's group at Queen Mary then calculated an orbit for the object.

A new found ring of material, S/2004 1 R, in the orbit of Saturn's moon Atlas has been seen in this view of the region between the edge of Saturn's A ring and the F ring.

Scientists cannot yet definitively say if the object is a moon or a temporary clump. If it is a moon, its diameter is estimated at four to five kilometers (two to three miles) and it is located 1,000 kilometers (620 miles) from the F ring, Saturn's outmost ring. It is at a distance of approximately 141,000 kilometers (86,000 miles) from the center of Saturn and within 300 kilometers (190 miles) of the orbit of the moon Pandora. The object has been provisionally named S/2004 S3.

Scientists are not sure if the object is alone. This is because of results from a search through other images that might capture the object to pin down its orbit. The search by Dr. Joseph Spitale, a planetary scientist working with team leader Dr. Carolyn Porco at the Space Science Institute in Boulder, Colo., revealed something strange. Spitale said, "When I went to look for additional images of this object to refine its orbit, I found that about five hours after first being sighted, it seemed to be orbiting interior to the F ring," said Spitale. "If this is the same object then it has an orbit that crosses the F ring, which makes it a strange object." Because of the puzzling dynamical implications of having a body that crosses the ring, the inner object sighted by Spitale is presently considered a separate object with the temporary designation S/2004 S 4. S4 is roughly the same size as S3.

In the process of examining the F ring region, Murray also detected a previously unknown ring, S/2004 1R, associated with Saturn's moon, Atlas. "We knew from Voyager that the region between the main rings and the F ring is dusty, but the role of the moons in this region was a mystery," said Murray. "It was while studying the F ring in these images that I discovered the faint ring of material. My immediate hunch was that it might be associated with the orbit of one of Saturn's moons, and after some calculation I identified Atlas as the prime suspect."

The ring is located 138,000 kilometers (86,000 miles) from the center of Saturn in the orbit of the moon Atlas, between the A ring and the F ring. The width of the ring is estimated at 300 kilometers (190 miles). The ring was first spotted in images taken after orbit insertion on July 1, 2004. There is no way of knowing yet if it extends all the way around the planet.

"We have planned many images to search the region between the A and F rings for diffuse material and new moons, which we have long expected to be there on the basis of the peculiar behavior of the F ring," said Porco. "Now we have found something but, as is usual for the F ring, what we see is perplexing."

Searches will continue for further detections of the newfound body or bodies seen in association with the F ring. If the two objects indeed turn out to be a single moon, it will bring the Saturn moon count to 34. The newfound ring adds to the growing number of narrow ringlets around Saturn.

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 Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. UK scientists are playing significant roles in the mission with involvement in six of the 12 instruments onboard the Cassini orbiter and two of the six instruments on the Huygens probe.

For images and information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. Images are also available at the Cassini imaging team home page, http://ciclops.org.
A small new found object, temporarily designated S/2004 S 3, has been seen orbiting Saturn's outer F ring. The tiny object, seen in this movie centered in a green box, orbits the planet at a distance of approximately 141,000 kilometers (86,420 miles) from the center of Saturn. Its nature, moon or clump, is not presently known.

PIA06115: New Object in F ring

A small new found object, temporarily designated S/2004 S 3, has been seen orbiting Saturn's outer F ring. The tiny object, seen in this movie centered in a green box, orbits the planet at a distance of approximately 141,000 kilometers (86,420 miles) from the center of Saturn. Its nature, moon or clump, is not presently known.

This movie is a sequence of 18 images taken with the Cassini spacecraft narrow angle camera on June 21, 2004. Images were taken every eight minutes over the course of two and one-quarter hours. Each image has been enhanced to show the presence of the newly detected object.

In the first frame, the small moon Atlas (32 kilometers or 20 miles across) can be seen near the main rings at lower left. About one-third of the way through the sequence the moon Janus (181 kilometers or 112 miles across) appears in two images at upper right.

The size of the object has been estimated to be four to five kilometers (two to three miles) across. Because it is so small, it is not resolved and appears as a faint point of light just barely visible above the background noise.

These images, which are part of a sequence specifically designed to search for small new moons in the inner Saturnian system, have not been cleaned of artifacts but have been greatly enhanced in contrast to increase visibility. Consequently, the main rings are overexposed, and many cosmic ray hits and noise patterns are clearly apparent. The image scale is approximately 40 kilometers (25 miles) per pixel.

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 imaging team is based at the Space Science Institute, Boulder, Colo.

该动画连接：
http://photojournal.jpl.nasa.gov/catalog/PIA06115

哇塞！厉害！不过土星环怎么那么亮啊！

彩色的图更漂亮啊。。

恩！