UH find of two new Jupiter moons is confirmed

By Christie Wilson
Advertiser Neighbor Island Editor

Astronomers from the University of Hawai'i have announced the discovery of two new moons around Jupiter.

During the past three years, a team led by UH astronomer David Jewitt and graduate student Scott Sheppard has identified 46 of the 63 known moons — also known as satellites — orbiting Jupiter, the largest planet in our solar system.

The data was collected using the Canada-France-Hawai'i Telescope, the UH Reflecting Telescope and the Subaru Telescope, all atop Mauna Kea.

The two newly identified moons were first observed last year, but the identification was just confirmed.

They are among Jupiter's smallest satellites, at about 1.2 miles in diameter, Sheppard said yesterday. Its largest known satellite is about 100 miles in diameter.

Sheppard said astronomers predict there may be as many as 100 satellites in regular and irregular orbits around Jupiter.

The satellites fall into six distinct groupings, each produced from a much larger satellite that was broken apart in a collision with a passing comet or another satellite, he said. The capture of the satellites by Jupiter probably occurred in the very early solar system, and studying them is helping scientists understand how planets were formed, Sheppard said.

Like almost all of the other satellites found in recent years, the newest discoveries are in retrograde orbits, meaning they orbit in the opposite direction of the planet's spin.

For those keeping track, Mercury and Venus have no moons, Earth has one, Mars two, Saturn 31, Uranus 27, Neptune 13 and Pluto one.

Jupiter is visible to stargazers this month. It rises in the east around 9 p.m. and is one of the brightest natural objects in the sky.

Reach Christie Wilson at (808) 244-4880 or at cwilson@honoluluadvertiser.com.