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News Release 46 of 96

June 5, 2003 09:00 AM (EDT)

News Release Number: STScI-2003-16

Supernova Shock Wave Paints Cosmic Portrait

A Hubble Heritage Release

June 5, 2003: Remnants from a star that exploded thousands of years ago created a celestial abstract portrait, as captured in this NASA Hubble Space Telescope image of the Pencil Nebula. Officially known as NGC 2736, the Pencil Nebula is part of the huge Vela supernova remnant, located in the southern constellation Vela. Discovered by Sir John Herschel in the 1840s, the nebula's linear appearance triggered its popular name. The nebula's shape suggests that it is part of the supernova shock wave that recently encountered a region of dense gas. It is this interaction that causes the nebula to glow, appearing like a rippled sheet.

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Q & A: Understanding the Discovery

  1. 1. What does the photo show?

  2. The photo shows the edge of the undulating sheet of gas. In this view, astronomers see large, wispy filamentary structures, smaller bright knots of gas, and patches of diffuse gas. The nebula's luminous appearance comes from dense gas regions that have been struck by the supernova shock wave. As the shock wave travels through space [from right to left in the image], it rams into interstellar material. Initially the gas is heated to millions of degrees, but then subsequently cools down, emitting the optical light visible in the image.

  3. 2. What do the colors of the nebula mean?

  4. The colors show the temperature of the various gases that make up the nebula. The gases are cooling down. Some regions, though, are still very hot. They are dominated by ionized oxygen atoms, which glow blue in the picture. The red regions (dominated by cooler hydrogen atoms) are cooler areas of gas.

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Image Credit: NASA and The Hubble Heritage Team (STScI/AURA)

Acknowledgment: W. Blair (JHU) and D. Malin (David Malin Images)