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Showing posts with label SN1572 - Tycho's Supernova. Show all posts
Showing posts with label SN1572 - Tycho's Supernova. Show all posts

Wednesday, July 23, 2014

Four Supernova Remnants


In commemoration of the 15th anniversary of NASA's Chandra X-ray Observatory, four newly processed images of supernova remnants dramatically illustrate Chandra's unique ability to explore high-energy processes in the cosmos (see the accompanying press release).

The images of the Tycho and G292.0+1.8 supernova remnants show how Chandra can trace the expanding debris of an exploded star and the associated shock waves that rumble through interstellar space at speeds of millions of miles per hour. The images of the Crab Nebula and 3C58 show how extremely dense, rapidly rotating neutron stars produced when a massive star explodes can create clouds of high-energy particles light years across that glow brightly in X-rays.

Tycho:
More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of the exploded star produced a shock wave moving outward into the surrounding interstellar gas, and another, reverse shock wave moving back into the expanding stellar debris. This Chandra image of Tycho reveals the dynamics of the explosion in exquisite detail. The outer shock has produced a rapidly moving shell of extremely high-energy electrons (blue), and the reverse shock has heated the expanding debris to millions of degrees (red and green). There is evidence from the Chandra data that these shock waves may be responsible for some of the cosmic rays - ultra-energetic particles - that pervade the Galaxy and constantly bombard the Earth.

G292.0+1.8:
At a distance of about 20,000 light years, G292.0+1.8 is one of only three supernova remnants in the Milky Way known to contain large amounts of oxygen. These oxygen-rich supernovas are of great interest to astronomers because they are one of the primary sources of the heavy elements (that is, everything other than hydrogen and helium) necessary to form planets and people. The X-ray image from Chandra shows a rapidly expanding, intricately structured, debris field that contains, along with oxygen (yellow and orange), other elements such as magnesium (green) and silicon and sulfur (blue) that were forged in the star before it exploded.

The Crab Nebula:
In 1054 AD, Chinese astronomers and others around the world noticed a new bright object in the sky. This “new star” was, in fact, the supernova explosion that created what is now called the Crab Nebula. At the center of the Crab Nebula is an extremely dense, rapidly rotating neutron star left behind by the explosion. The neutron star, also known as a pulsar, is spewing out a blizzard of high-energy particles, producing the expanding X-ray nebula seen by Chandra. In this new image, lower-energy X-rays from Chandra are red, medium energy X-rays are green, and the highest-energy X-rays are blue.

3C58:
3C58 is the remnant of a supernova observed in the year 1181 AD by Chinese and Japanese astronomers. This new Chandra image shows the center of 3C58, which contains a rapidly spinning neutron star surrounded by a thick ring, or torus, of X-ray emission. The pulsar also has produced jets of X-rays blasting away from it to both the left and right, and extending trillions of miles. These jets are responsible for creating the elaborate web of loops and swirls revealed in the X-ray data. These features, similar to those found in the Crab, are evidence that 3C58 and others like it are capable of generating both swarms of high-energy particles and powerful magnetic fields. In this image, low, medium, and high-energy X-rays detected by Chandra are red, green, and blue respectively.

Image credit: NASA/CXC/SAO

Wednesday, July 14, 2010

SN 1572 - Tycho Brahe's Supernova


This image from NASA's Wide-field Infrared Survey Explorer (WISE) takes in several interesting objects in the constellation Cassiopeia, none of which are easily seen in visible light.

The red circle visible in the upper left part of the image is SN 1572, often called "Tycho's Supernova." This remnant of a star explosion is named after the astronomer Tycho Brahe, although he was not the only person to observe and record the supernova. When the supernova first appeared in November 1572, it was as bright as Venus and could be seen in the daytime. Over the next two years, the supernova dimmed until it could no longer be seen with the naked eye. It wasn't until the 1950s that the remnants of the supernova could be seen again with the help of telescopes.

When the star exploded, it sent out a blast wave into the surrounding material, scooping up interstellar dust and gas as it went, like a snow plow. An expanding shock wave traveled into the surroundings and a reverse shock was driven back in toward the remnants of the star. Previous observations by NASA's Spitzer Space Telescope indicate that the nature of the light that WISE sees from the supernova remnant is emission from dust heated by the shock wave.

In the center of the image is a star-forming nebula of dust and gas, called S175. This cloud of material is about 3,500 light-years away and 35 light-years across. It is being heated by radiation from young, hot stars within it, and the dust within the cloud radiates infrared light.

On the left edge of the image, between the Tycho supernova remnant and the very bright star, is an open cluster of stars, King 1, first cataloged by Ivan King, an astronomer at UC Berkeley, California. [Dr. King was at Cal when he discovered King 1; he now teaches at the University of Washington.] This cluster is about 6,000 light-years away, 4 light-years across and is about 2 billion years old.

Also of interest in the lower right of the image is a cluster of infrared-emitting objects. Almost all of these sources have no counterparts in visible-light images, and only some have been cataloged by previous infrared surveys. There are indications that they may be young stellar objects associated with a dense nebula in the area. Young stellar objects (YSOs) are stars in their earliest stages of life. YSOs are surrounded by an envelope of dust, which would explain the very red color of the sources in this image.

All four infrared detectors aboard WISE were used to make this mosaic. The image spans an area of 1.6 x 1.6 degrees on the sky or about 3 times as wide and high as the full moon. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA