500th comet found by SOHO
NASA-GSFC NEWS RELEASE
Posted: August 14, 2002

  Comet
Photo: NASA/ESA
 
Amateur astronomers worldwide placed their bets, crossed their fingers and waited in anticipation for the ESA-NASA Solar & Heliospheric Observatory (SOHO) spacecraft to spot its 500th comet. Their patience was rewarded on August 12 as SOHO, a mission actually designed to research the Sun, revealed its own type of royal flush with comet C/2002 P3 (SOHO).

It is the 500th comet to be discovered by SOHO since it launched on December 2, 1995, making the spacecraft by far the most prolific comet-hunting observatory in history.

Between May 2 and May 31, using the SOHO website, 1,256 amateur astronomers tracked SOHO's observations of comets and made predictions about the date and time that the 500th comet would be at perihelion (the closest approach to the Sun). Comet C/2002 P3 (SOHO) had a perihelion time of August 12 at 12:04:48 p.m. EST.

Diane McElhiney won the sweepstakes with a prediction only one hour and 43 minutes away from the correct time.

The website also allows comet aficionados around the world to look at real-time SOHO data and images. Once they see what appears to be a new comet, they seek confirmation from others on-line. If confirmation is provided, they have accomplished a feat that is the goal of many amateur astronomers.

More than 75 percent of the comet discoveries have come from amateurs from Australia, Canada, China, France, Germany, Italy, Lithuania, Russia, the United Kingdom and the United States.

"Analyzing SOHO data is a great challenge and you have to combine many skills," said Rainer Kracht, the discoverer of C/2002 P3 (SOHO). "But every amateur astronomer dreams of finding a comet."

Kracht, a mathematics, physics, computer science and astronomy teacher at the Kooperative Gesamtschule Elmshorn in Elmshorn, Germany, has discovered 63 comets since August 2001 with the help of SOHO data and images. An entire group of near Sun comets that he discovered is even named after him - the Kracht group.

C/2002 P3 (SOHO) is not only an unanticipated milestone for the mission, but whereas most near Sun comets are of the Kreutz family, C/2002 P3 (SOHO) is a member of a family of comets called the Meyer group. The Meyer group is one of three new families that have been discovered with SOHO data. A comet family is a group of comets that originated from the same place and follow the same path. C/2002 P3 (SOHO) has a perihelion distance of 5.37 million km from the Sun.

"We don't yet know much about this family, or the other new families," said Dr. Doug Biesecker, the head of SOHO's comet discovery program stationed at NASA's Goddard Space Flight Center and a solar physicist with L3 Com Analytics Corporation. "With such few known members of this family, we need every additional comet we can get."

The use of SOHO as a tool to discover comets is a byproduct of the mission's original purpose - to continuously monitor solar weather and assist scientists in analyzing how the Sun functions. The Large Angle and Spectrometric Coronagraph (LASCO), one of the instruments on SOHO, blocks out the Sun to create an artificial eclipse and then views the space around the Sun, looking for outbursts of solar activity. This eclipse allows the Sun's faint outer atmosphere (corona) to be seen and studied.

Like the corona, comets that would usually be lost in the glare of the Sun unexpectedly come into LASCO's field of view. Almost all of them end up vaporized in the solar atmosphere. In spite of the fact that the SOHO Kreutz family comets tend to be only 10 meters in diameter, they are fragments of a comet that was originally much larger, maybe 100 km in diameter. This is so large, in fact, that it might have been visible during daylight more than 2000 years ago.

"Though LASCO was not originally built for this purpose, no other instrument has discovered more of these comets," said Dr. Bernhard Fleck, ESA Project Scientist for SOHO stationed at Goddard. "It was a wonderful surprise, of the kind we get in science sometimes."

Hubble
Astronomy Now presents Hubble: the space telescope's view of the cosmos. A collection of the best images from the world’s premier space observatory.
 U.S. STORE
 U.K. & WORLDWIDE STORE
Apollo 15 DVD - offer ends soon
For a limited time only, preorder your Apollo 15 DVDs at a special discount price. Two- and six-disc editions of this unique DVD are coming soon.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Mission Report
Space Shuttle Flights 1-5: The NASA Mission Reports covers the shuttle through its test flight stage and on to the first operational flight. Includes CD-ROM.
 U.S. STORE
 WORLDWIDE STORE

John Glenn Mission Patch

Free shipping to U.S. addresses!

The historic first orbital flight by an American is marked by this commemorative patch for John Glenn and Friendship 7.
 U.S. STORE
 WORLDWIDE STORE

Final Shuttle Mission Patch

Free shipping to U.S. addresses!

The crew emblem for the final space shuttle mission is available in our store. Get this piece of history!
 U.S. STORE
 WORLDWIDE STORE

Celebrate the shuttle program

Free shipping to U.S. addresses!

This special commemorative patch marks the retirement of NASA's Space Shuttle Program. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Anniversary Shuttle Patch

Free shipping to U.S. addresses!

This embroidered patch commemorates the 30th anniversary of the Space Shuttle Program. The design features the space shuttle Columbia's historic maiden flight of April 12, 1981.
 U.S. STORE
 WORLDWIDE STORE

Mercury anniversary

Free shipping to U.S. addresses!


Celebrate the 50th anniversary of Alan Shephard's historic Mercury mission with this collectors' item, the official commemorative embroidered patch.
 U.S. STORE
 WORLDWIDE STORE

Fallen Heroes Patch Collection
The official patches from Apollo 1, the shuttle Challenger and Columbia crews are available in the store.
 U.S. STORE
 WORLDWIDE STORE

Columbia Report
The official accident investigation report into the loss of the space shuttle Columbia and its crew of seven. Includes CD-ROM.
 Choose your store:
U.S.

Apollo 12 tribute DVD set

New! Featuring the jovial crew of Pete Conrad, Dick Gordon and Alan Bean, the Apollo 12 mission was struck by lightning shortly after liftoff but proceeded on the second successful exploration voyage to the lunar surface. This three-disc DVD brings the mission to life with extraordinary detail.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Fallen Heroes special patch
This special 12-inch embroidered patch commemorates the U.S. astronauts who made the ultimate sacrifice, honoring the crews of Apollo 1, Challenger and Columbia.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Women in Space
Women of Space: Cool Careers on the Final Frontier is for girls, young women, and anyone else interested in learning about exciting careers in space exploration. Includes CD-ROM.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Mars rover poster
This new poster features some of the best pictures from NASA's amazing Mars Exploration Rovers Spirit and Opportunity.
 Choose your store:
U.S.

Station Calendar
NEW! This beautiful 12" by 12" wall calendar features stunning images of the International Space Station and of the people, equipment, and space craft associated with it, as it takes shape day by day in orbit high above the Earth.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Get e-mail updates
Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose).
Enter your e-mail address:

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.