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A Celestial Witch's Broom?
NGC 2736, Pencil Nebula
Description: Supernova Remnant
Position: RA: 9h 0m 12.02s Dec: -45° 57' 0.24"
Distance: 800 light years
Field of view: 33.16 x 33.16 arcminutes
Orientation: North is 90.1° left of vertical
Image Credit: ESO
Release date: September 12, 2012
2003 Hubble image: N0316
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ABOUT THIS IMAGE:
Despite the tranquil and apparently unchanging beauty of a starry night, the Universe is far from being a quiet place. Stars are being born and dying in an endless cycle, and sometimes the death of a star can create a vista of unequalled beauty as material is blasted out into space to form strange structures in the sky.
new image from the Wide Field Imager on the MPG/ESO 2.2-meter telescope
at ESO's La Silla Observatory in Chile shows the Pencil Nebula against
a rich starry background. This oddly shaped cloud, which is also known
as NGC 2736, is a small part of a supernova remnant in the southern constellation
of Vela (The Sails). These glowing filaments were created by the violent
death of a star that took place about 11 000 years ago. The brightest
part resembles a pencil; hence the name, but the whole structure looks
rather more like a traditional witch's broom.
This new image shows 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, it rams into the interstellar material. At first, the gas was heated to millions of degrees, but it then subsequently cooled down and is still giving off the faint glow that was captured in the new image.
By looking at the different colors of the nebula, astronomers have been able to map the temperature of the gas. Some regions are still so hot that the emission is dominated by ionized oxygen atoms, which glow blue in the picture. Other cooler regions are seen glowing red, due to emission from hydrogen.
The Pencil Nebula measures about 0.75 light-years across and is moving through the interstellar medium at about 650 000 kilometers per hour. Remarkably, even at its distance of approximately 800 light-years from Earth, this means that it will noticeably change its position relative to the background stars within a human lifetime. Even after 11 000 years the supernova explosion is still changing the face of the night sky.
The Pencil Nebula, sometimes nicknamed Herschel's Ray, was discovered by British astronomer John Herschel back in 1835 while he was in South Africa. He described it as "an extraordinary long narrow ray of excessively feeble light".
A supernova is a violent stellar explosion, resulting from the death of
either a high-mass star or a white dwarf in a close double star system.
The structure resulting from the explosion is called the supernova remnant.
This consists of ejected material expanding at supersonic velocities into
the surrounding interstellar medium. Supernovae are the main source of
the heavier chemical elements in the interstellar medium, which in turn
leads to the chemical enrichment of a new generation of stars and planets.