Comparing Comets and Asteroids

Water Discovered on Second Asteroid, May Be Even More Common Than Expected

Water ice on asteroids may be more common than expected, according to a new study.

A UCF researcher who made national headlines for showing the first evidence of water ice and organic molecules on an asteroid has discovered another one. Image Credit: Gabriel Pérez, Instituto de Astrofisica de Canarias, Spain

Two teams of researchers who made national headlines in April for showing the first evidence of water ice and organic molecules on an asteroid have now discovered that asteroid 65 Cybele contains the same material.

“This discovery suggests that this region of our solar system contains more water ice than anticipated,” said University of Central Florida Professor Humberto Campins. “And it supports the theory that asteroids may have hit Earth and brought our planet its water and the building blocks for life to form and evolve here.”

Campins presented the teams’ findings during the 42nd annual meeting of the American Astronomical Society’s Division for Planetary Sciences (DPS) in Pasadena, Calif.

Asteroid 65 Cybele is somewhat larger than asteroid 24 Themis — the subject of the teams’ first paper. Cybele has a diameter of 290 km (180 miles). Themis has a diameter of 200 km (124 miles). Both are in the same region of the asteroid belt between Mars and Jupiter.

The academic article reporting this new finding has been accepted for publication in the European Journal “Astronomy and Astrophysics.”

New Clue to Whether Phaeton is an Asteroid or a Comet

In another talk at the DPS meeting, Campins presented new findings about the asteroid 3200 Phaethon.

There are hundreds of asteroids in space, like this one named Ida. It also is found in the asteroid belt between Mars and Jupiter. Credit: NASA JPL/California Institute of Technology

This asteroid sometimes acts like a comet, lighting up the Earth’s night sky with meteor showers. Sometimes it’s like an asteroid, a hunk of rock floating in space.

Phaethon has baffled scientists for years, because it doesn’t behave the way they expect. But Campins and his team may have uncovered a major clue — Phaethon’s daddy.

Using telescopes and mathematical modeling, researchers looked at the chemical composition – the DNA fingerprint – of Phaethon and compared it to the composition of the second-largest asteroid found in the main asteroid belt located between Mars and Jupiter. They found significant similarities between Phaethon and 2 Pallas.

“Pallas and Phaethon appear to be father and son,” Campins said. “But the son doesn’t act anything like dad.”

Based on the results, the team, which includes scientists from Spain, Greece and France, believes that the size of asteroids and their orbits play a role in how they act.

Phaethon’s orbit crosses the Earth’s orbit, and debris left by Phaethon in its orbit produces the Geminid meteor shower every December. In addition, Phaethon probably contains organic material that may have been part Earth before life, as we know it, developed here.

So what should we call Phaethon? Campins smiles.

“It just shows you that Mother Nature doesn’t care what we call it,” Campins said. “She will continue to amaze us, regardless of what we call her wonders.”