Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 3 
Posted on 09/03/2003 5:34:54 AM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 3
Explanation: About 8000 years ago, a star in our Galaxy exploded. Ancient humans might have noticed the supernova as a temporary star, but modern humans can see the expanding shell of gas even today. Pictured above, part of the shell of IC 443 is seen to be composed of complex filaments, some of which are impacting an existing molecular cloud. Here emission from shock-excited molecular hydrogen is allowing astronomers to study how fast moving supernova gas affects star formation in the cloud. Additionally, astronomers theorize that the impact accelerates some particles to velocities near the speed of light. Supernova remnant IC 443 is also known to shine brightly also in infrared and X-ray light.
| Right Ascension: | 6 : 16.9 (hours : minutes) |
|---|---|
| Declination: | +22 : 47 (degrees : minutes) |
| Apparent Magnitude: | not given |
| Apparent Diameter: | 50. (arc minutes) |
Here is an amateur wide-angle photo of IC443. The flanking stars are Tejat Posterior (mu Geminorum) [left], magnitude 2.84, and Tejat Prior, or Propus (eta Geminorum) [right], magnitude 3.28. Here is what the photographer says about it:
IC443 lies in the constellation of Gemini between the stars mu and eta Gemini. Although the location is easy to find, the nebula is not. It will require a telescope of 30cm of aperture or greater and a UHC or OIII filter to see. Observing it with a 50cm telescope from dark skies, the main portion of the nebula is reported as a ghostly arc of light using an OIII filter. IC443 can be imaged relatively easily on film and, because of its size, is more suited to film than to imaging with CCDs unless they are mounted on a wide field refractor or photographic lens rather than a telescope.
Students using NASA and NSF data make stellar discovery; win science team competition
Three high school students, using data from NASA's Chandra X-ray Observatory and the National Science Foundation's Very Large Array (VLA), today won first place in the Siemens-Westinghouse Science and Technology Competition in Washington, DC. The team award was based on their discovery of the first evidence of a neutron star in the nearby supernova remnant IC443.
Charles Olbert, 18, Christopher Clearfield, 18, and Nikolas Williams, 16, all of the North Carolina School for Science and Mathematics (NCSSM) in Durham, N.C., found a point-like source of X-rays embedded in the remains of the stellar explosion, or supernova. Based on both the X-ray and radio data, the students determined that the central object in IC443 is most likely a young and rapidly rotating neutron star — an object known as a pulsar.
"This is a really solid scientific finding," said Dr. Bryan Gaensler of the Massachusetts Institute of Technology, Cambridge, a pulsar expert who reviewed the paper for the team. "Everyone involved should be really proud of this accomplishment."
Taking advantage of Chandra's superior angular resolution, the students found the source embedded in a region known to be emitting particularly high-energy X-rays. They had access to Chandra data because their science teacher,
Dr. Jonathan Keohane, had applied for observation time while associated with NASA's Goddard Space Flight Center, Greenbelt, M.D.
"The students really went through the whole analysis process themselves," Keohane said. "They even lived together all summer near the school to complete the research."
In order to confirm the evidence from Chandra, the students turned to Dale Frail of the National Radio Astronomy Observatory in Socorro, N.M., who gave the team VLA data on IC443. The information strengthened the team's case that a pulsar powers the supernova remnant by confirming the existence of the point-like source and discovering a cloud, or nebula, of high-energy electrons around the central object. Such nebulas are a common characteristic of pulsars.
"The experience of doing new and relevant science has been one of the most rewarding experiences I have ever had," said Olbert, lead author on the paper submitted to the Astrophysical Journal. "I never expected to publish a scientific paper while I was still in high school."
The remnant of the IC443 supernova is a well-studied object. Astronomers have searched this region (approximately 5,000 light-years from Earth) for the neutron star, created in the explosion, that they thought should be there, judging from the size and dynamics of the supernova remnant.
The Siemens-Westinghouse Science and Technology Competition is open to individuals and teams of high school students who develop independent research projects in the physical or biological sciences or mathematics. The NCSSM is a free statewide residential high school for students with a strong aptitude and interest in math and science. About 550 high school juniors and seniors reside on the school's campus.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program.
The Smithsonian's Chandra X-ray Center, Cambridge, Mass., controls science and flight operations.
For more information on NASA’s Chandra X-ray Observatory, visit the Chandra site at:
and
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