Supernova Remnants
Overview
A supernova remnant is a nebulous structure that forms from a supernova. The exploding star sends out ejected material and sweeps up the interstellar gas to form these nebulous, glowing clouds of gas.
The Crab Nebula, located in Taurus, is a remnant from the supernova of 1054. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)
What is a Supernova?
A supernova is a star in its death throes, resulting in a spectacularly luminous explosion. A supernova occurs under two scenarios: when a massive star (greater than about nine solar masses) runs out of fuel, or when an accreting white dwarf is triggered into “coming alive” with runaway nuclear fusion.
In the case of a massive star, once hydrogen is exhausted in its core, it will begin “burning” helium to maintain the hydrostatic balance. As successive elements are exhausted, the core “burns” heavier elements until reaching iron, at which point the core cannot support itself and collapses into a black hole or neutron star, causing a violent explosion and sending the outer layers of the star into interstellar space. This core collapse is the reason for most supernovae.
A view of supernova remnants, in orange, near the Sun in the Milky Way Galaxy. The Sun lies at the center of the white ring. Many notable remnants are visible: the Crab Nebula from the supernova of 1054, the Tycho remnant from the 1572 supernova observed by Tycho Brahe. Cassiopeia A is at the bottom right of the frame, believed to be from a supernova around 1690.
The Nebulous Remnant
The result of a supernova is the expulsion of much of the stellar material into interstellar space. The gas sweeps out at hypersonic speeds, sweeping up any intervening gas and exciting it. Remnants have a pulsar or neutron star at their center, the remaining core of the dead star. Many supernova remnants are shell-like in appearance, but some take on jets from the pulsar inside them.
Short Lifetimes
Eventually, the expansion speed will slow to the speed of the ambient interstellar gas. This entire process takes around 30,000 years, so these objects are visible over an extremely short period of time, cosmically speaking, before they fade into the surrounding gas.
Scant Data?
Supernovae are a relatively rare occurrence. Only a tiny fraction of stars or binary systems will result in a supernova. On top of that, the remnant phase is relatively short—on the order of tens of thousands of years. So, we do not expect to see too many of these at any given time.
Furthermore, it is difficult to obtain accurate distances for these objects. Fewer than half the catalog’s objects have reliable distances.
A view of the night sky toward Orion with the supernova remnants as orange points. The Crab Nebula from the supernova of 1054, is a famous remnant that is easy to see with a telescope.
Location in the Galaxy
Similar to all objects that depend on, or are the product of star formation, supernova remnants are found in the disk of the Galaxy, where stars are bring formed and massive stars are dying out. So, these objects are tightly confined to the Milky Way’s disk.
Notable Objects
There are a handful of notable supernova remnants. We mentioned the Crab Nebula from 1054 and the Tycho remnant, named for the astronomer Tycho Brahe who observed the supernova of 1572. Similarly, there is a Kepler remnant from the 1604 supernova. Visible in the southern hemisphere is the Vela remnant. It originated about 11,000 years ago from a supernova about 900 light years away. It is one of the closest to Earth and one of the brightest X-ray sources in the night sky.
Some notable supernova remnants around the Sun.
Profiles
Dossier
Census: |
112 supernova remnants |
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Asset File: |
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OpenSpace Version: |
3 |
Reference: |
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Prepared by: |
Brian Abbott, Zack Reeves (AMNH) |
Source Version: |
4.08 |
License: |