Telescopes Find a Miniplanet at the Solar System's Edge

[Dave Monroe]

The New York Times
Tuesday, October 8, 2002
Telescopes Find a Miniplanet at the Solar System's
Edge
By JOHN NOBLE WILFORD

Looking beyond the known planets of the Sun, out among
an orbiting multitude of small icy bodies, astronomers
have seen and measured a miniplanet, more than half
the size of Pluto, that is the largest object in the
solar system to be detected since the discovery of
Pluto in 1930.

A ball of ice and rock about 800 miles in diameter,
the object is well over a billion miles farther out
than Pluto and some four billion miles from Earth. It
is in a region known as the Kuiper Belt, where comets
originate and nearly everything is a relic of the
solar system's formative epoch.

Some planetary researchers also think this discovery
undermines the belief that Pluto is a planet.

[...]

Two astronomers at the California Institute of
Technology, using a telescope at the Palomar
Observatory near San Diego, detected the faint light
of the object in June and calculated its distance and
its unusually circular orbit. The planetary
researchers, Dr. Michael E. Brown and Dr. Chadwick
Trujillo, have proposed naming the object Quaoar
(pronounced KWAH-o-ar), the creator god of an Indian
people who originally inhabited the Los Angeles basin.

[...]

"It's indicative that there are larger and larger
objects out there to be found," Dr. Brown said in a
telephone interview. "I would be very surprised if
there aren't things larger even than Pluto."

... In 1951, the Dutch-American astronomer Gerard
Kuiper hypothesized that other small bodies would be
found beyond the orbit of Neptune, the outermost giant
planet of the Sun.

Dr. Jewitt praised the new discovery, calling this "an
awesome new object" but no surprise. The new
miniplanet, he and other astronomers noted, is not
even the largest object already observed in the Kuiper
Belt.

In the opinion of many planetary astronomers, that
distinction belongs to Pluto itself. With a diameter
of 1,400 miles, Pluto is the smallest of the nine
planets and, they feel, should probably be classified
as a Kuiper Belt object, not a true planet. Scientists
suspect that it originated in that region and was
ejected into a Neptune-crossing orbit by some long-ago
gravitational disturbance.

"Quaoar definitely hurts the case for Pluto being a
planet," Dr. Brown said. "If Pluto were discovered
today, no one would even consider calling it a planet
because it's clearly a Kuiper Belt object."

Whether Pluto is a planet or not, Dr. Jewitt said,
recent studies have led to predictions of up to 10
objects in the Kuiper region that are as larger or
larger than Pluto. They will be more distant than
Pluto, thus fainter and harder to detect.

[...]

When Dr. Brown and Dr. Trujillo first caught sight of
Quaoar, they searched the Palomar archives and soon
found images of it taken as early as 1982, but not
recognized at the time. The images were from a survey
by Dr. Charles T. Kowal, then a Caltech astronomer
searching in vain for a hypothesized massive but
elusive planet known as Planet X.

[...]

The record of previous sightings allowed the
astronomers to establish the distance and plot the
object's orbital track. They could estimate that it
completes an orbit of the Sun every 288 years.

"It's probably been in this same orbit for four
billion years," Dr. Brown said.

[...]

Astronomers said the discovery was not so much a
triumph of new optics as of a highly focused search
strategy and computers that allow speedy analysis of
vast quantities of data that previously could only be
skimmed. It made Dr. Jewitt wonder, "Who knows what
else is out there?"

http://www.nytimes.com/2002/10/08/science/space/08ASTR.html

__________________________________________________
Do you Yahoo!?
Faith Hill - Exclusive Performances, Videos & More
http://faith.yahoo.com