home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The Starbase One Astronomy & Space Collection
/
STARBASE_ONE.ISO
/
hst
/
95_29.txt
< prev
next >
Wrap
Text File
|
1996-01-12
|
4KB
|
98 lines
Contact: Don Savage For Release: July 28, 1995
NASA Headquarters, Washington, DC
(Phone: 202-358-1547)
Tammy Jones
Goddard Space Flight Center, Greenbelt, MD
(Phone: 202-286-5566)
Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone: 410-338-4514)
Press Release No.: STScI-PR95-29
HUBBLE DISCOVERS NEW MOONS ORBITING SATURN
Astronomers have announced the discovery of at least two, and
possibly as many as four, new moons orbiting the giant planet
Saturn. This discovery was based upon NASA Hubble Space
Telescope images taken on May 22, 1995, when Saturn's rings were
tilted edge-on to Earth.
The discovery, reported in the July 27th International
Astronomical Union Telegram (Circular No. 6192), was made by
Amanda S. Bosh of Lowell Observatory, Flagstaff, AZ, and Andrew
S. Rivkin (also of Lowell Observatory and the University of
Arizona/Lunar and Planetary Laboratory).
"We were excited to see new satellites in the Hubble pictures.
This was not a primary goal of our observations, so we were quite
surprised," said Bosh.
Two of the satellites seen by Hubble are in orbits similar to
those of Atlas and Prometheus, a pair of moons discovered in 1980
by the Voyager 1 spacecraft. "If these two satellites are the
same seen by Voyager, then their orbital longitudes are different
from what we expected," said Bosh.
Additional Hubble observations of Saturn, taken when the Earth
again crosses the ring plane on August 10, will provide more
images that can be used to determine whether two of the four
satellites detected by Hubble are truly new or not. If all four
satellites are new, then the total number of known moons orbiting
Saturn will grow from 18 to 22.
Two of the new moons (called S/1995 S1 and S2) lie inside
Saturn's thin, eccentric "F" ring; a third moon (S3) lies just
outside the F ring; and the fourth moon (S4) is 3,700 miles
(6,000 kilometers) beyond the F ring. The moons are no bigger
than about 45 miles (70 kilometers) across.
Hubble's sharp view is ideal for detecting faint new satellites
that have previously gone unseen. The astronomers identified the
new moons by first processing the Hubble pictures to remove
residual light from the ring edge, and noting the locations of
Saturn's known satellites. After this was done, the researchers
saw four objects moving from frame to frame that did not
correspond with any of the known satellites. "With the exception
of S4, which we're having trouble finding in a few frames, we can
follow the other three satellites for 10 hours as they go around
the planet," said Bosh.
Saturn ring plane crossings happen only once every 15 years, and
historically have given astronomers an opportunity to discover
new satellites that are normally lost in the glare of the
planet's bright ring system. Astronomers discovered 13 of
Saturn's moons during ring-plane crossings from 1655 to 1980.
Other satellites were identified during the Voyager spacecraft
flybys of Saturn in the early 1980s.
After the upcoming August 10 ring plane crossing, the next such
event that will be visible from Earth won't occur until the year
2038. (Saturn will be edge-on in 2009 and 2025, but will be too
close to the Sun to be observed from Earth.)
* * * * *
The Space Telescope Science Institute is operated by the
Association of Universities for Research in Astronomy, Inc.
(AURA) for NASA, under contract with the Goddard Space Flight
Center, Greenbelt, MD. The Hubble Space Telescope is a project
of international cooperation between NASA and the European Space
Agency (ESA).
Image files in GIF and JPEG format may be accessed on Internet
via anonymous ftp from ftp.stsci.edu in /pubinfo:
GIF JPEG
PRC95-29 New Satellite of Saturn S1995S3.gif S1995S3.jpg
The same images are available via World Wide Web from URL
http://www.stsci.edu/Latest.html or via links in
http://www.stsci.edu/Pictures.html.
NOTE TO EDITORS: Hard copies of this image are not yet available.