When their nuclear fuel is exhausted, the most massive stars explode in a spectacular fashion, called a supernova , leaving behind neutron stars, black holes or nothing at all. The last time astronomers observed a supernova in our galaxy was in the s. Three years later, Hubble began to monitor the explosion — called Supernova A — from the first-ever ringside seat for a supernova.
Hubble has observed the nebula remnant of Supernova A repeatedly, witnessing rings and knots of gas brightening around the exploded star. Watching the supernova in progress for decades has led to a greater understanding of how these events play out over thousands of years. Radiation from the white dwarf causes the gas to glow, creating a unique and beautiful formation called a planetary nebula.
The name comes from the early days of astronomy, when observers thought the dim forms they saw through their telescopes might be related to planets.
Today, Hubble has observed many of these nebulas and found a wide range of complicated and extraordinary shapes, from tunnels to interlocking rings. The Cat's Eye Nebula, for example, consists of 11 bubbles of gas. The Helix Nebula looks like a giant eye staring at us through space.
The Red Rectangle — one of the weirdest planetary nebulas of all — appears exactly as sounds. This variation does more than provide us with a wealth of beautiful images — it shows the diversity of the stars and processes that gave rise to these structures. Though the dynamics that create such intricate structures in a relatively short time are still mysterious, each Hubble image helps us understand a little more about how Sun-like stars spend their final years.
Understanding the Lifecycles of Stars. On This Page. Visible and Infrared Visualization of the Orion Nebula. Star Forming Nebula. How Do Stars Form in Nebulas? SNRs are extremely important for understanding our galaxy. They heat up the interstellar medium, distribute heavy elements throughout the galaxy, and accelerate cosmic rays.
Naturally, if the supernova explosion was recorded in history, as is the case of many SNRs less than a few thousand years old, we know the age of the corresponding SNR.
However, sometimes historians are not certain if a recorded "guest star" was a supernova or was the same supernova as a corresponding remnant. It is therefore important to be able to estimate the age of SNRs. An easy way to guess the age of a SNR is to measure the temperature of the hot gas using X-ray spectroscopy. From this observation we can estimate the velocity of the shock wave, and then infer the age from the shock velocity.
In the modern era, one of the more famous supernovas was SN A from , which is still being studied by astronomers because they can see how a supernova evolves in the first few decades after the explosion. On average, a supernova will occur about once every 50 years in a galaxy the size of the Milky Way. Put another way, a star explodes every second or so somewhere in the universe, and some of those aren't too far from Earth.
Exactly how a star dies depends in part on its mass. Our sun, for example, doesn't have enough mass to explode as a supernova though the news for Earth still isn't good, because once the sun runs out of its nuclear fuel, perhaps in a couple billion years, it will swell into a red giant that will likely vaporize our world, before gradually cooling into a white dwarf. But with the right amount of mass, a star can burn out in a fiery explosion.
Let's look at the more exciting Type II first. For a star to explode as a Type II supernova , it must be at several times more massive than the sun estimates run from eight to 15 solar masses. Like the sun, it will eventually run out of hydrogen and then helium fuel at its core. However, it will have enough mass and pressure to fuse carbon.
Here's what happens next:. What's left is an ultra-dense object called a neutron star , a city-sized object that can pack the mass of the sun in a small space. The ALMA data do not cover the full image shown here. Select Language en. Science User Portal. Subscribe Contact Site Map. Open Menu. Xavier Barcons Prof. Cesarsky Prof.
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