[meteorite-list] Jupiter's Moon Count Soars to 52 with Four New Discoveries

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:23:46 2004
Message-ID: <200303101727.JAA02411_at_zagami.jpl.nasa.gov>

http://www.space.com/scienceastronomy/jupiter_moons_030310.html

Jupiter's Moon Count Soars to 52 with Four New Discoveries
By Robert Roy Britt
space.com
10 March 2003

The tally of Jovian moons has soared to 52 with the discovery of four
small moons added to eight that were previously revealed last week. The
total may represent roughly half of all the giant planet's satellites
larger than 0.62 miles (1 kilometer).

The discoveries were made by a team led by Scott Sheppard and David
Jewitt of the University of Hawaii's Institute for Astronomy. They came
fast and furious, in three separate revelations beginning March 5.

"We haven't even had a press release about the satellites," Jewitt said
in an e-mail interview. "We just put up a web site and then we start
getting calls from all over the world. People love this stuff, as we do."

Included in the latest batch are two rocks estimated to be just 0.62
miles (1 kilometer) in diameter. These are the first Jovian satellites
calculated to be less than 2 kilometers. Jupiter has 29 moons that are
no more than 2.5 miles (4 kilometers) wide and several more that aren't
much bigger. These small satellites are thought to be captured asteroids
or chunks of larger objects that broke apart, though their exact origins
have not been determined. Many of them orbit in a direction opposite the
planet's rotation.

SPACE.com asked Jewitt if the tiny objects deserve to be called moons at
all, or whether perhaps a new class of object should be conjured to
account for the micromoons.

"No," Jewitt said to the latter suggestion. "To me they're all natural
satellites. Is a small dog not a dog because it is small?"

Jewitt estimates that Jupiter might have 100 satellites down to the
1-kilometer range, though he stresses that this is just a guess. Countless
smaller rocks and bits of dust are in the planet's gravitational clutches.

No other planet has more known satellites. Saturn has 30, Uranus 21 and
Neptune 11. Each of these planets likely harbors more moons that have not
been spotted because the planets are farther out in the solar system and
harder to examine.

Mars has two moons and Earth has just one, although a separate effort
recently uncovered a quasi-moon that carves an odd path that is
gravitationally bound to our planet. Pluto also has a moon, Charon.

Jupiter has four large satellites, too, called the Galilean moons for
their discoverer. The largest is Ganymede, which is about 3,270 miles
(5,262 kilometers) wide.

The new satellites are named S/2003 J1 through S/2003 J12. Jewitt said
his team will continue its search and he expects more discoveries.
Using the Subaru and Canada-France-Hawaii telescopes on Mauna Kea in
Hawaii, the team has found 35 Jovian satellites in recent years.
Received on Mon 10 Mar 2003 12:27:58 PM PST