Why is supernova 1987a important to astronomers

Type Ia supernovae are ignited when a lot of material is dumped on degenerate white dwarfs Figure 2 ; these supernovae will be discussed later in this chapter. For now, we will continue our story about the death of massive stars and focus on type II supernovae, which are produced when the core of a massive star collapses. Figure 2: Supernova J. This image of supernova J, located in Messier 82 M82 , which is also known as the Cigar galaxy, was taken by the Hubble Space Telescope and is superposed on a mosaic image of the galaxy also taken with Hubble.

The supernova event is indicated by the box and the inset. This explosion was produced by a type Ia supernova, which is theorized to be triggered in binary systems consisting of a white dwarf and another star—and could be a second white dwarf, a star like our Sun, or a giant star. This type of supernova will be discussed later in this chapter. At a distance of approximately In the image, you can see reddish plumes of hydrogen coming from the central region of the galaxy, where a considerable number of young stars are being born.

Our most detailed information about what happens when a type II supernova occurs comes from an event that was observed in Before dawn on February 24, Ian Shelton, a Canadian astronomer working at an observatory in Chile, pulled a photographic plate from the developer.

Where he expected to see only faint stars, he saw a large bright spot. Concerned that his photograph was flawed, Shelton went outside to look at the Large Magellanic Cloud.

He soon realized that he had discovered a supernova, one that could be seen with the unaided eye even though it was about , light-years away. The supernova remnant with its inner and outer red rings of material is located in the Large Magellanic Cloud.

This image is a composite of several images taken in , , and —about a decade after supernova A was first observed. Now known as SN A, since it was the first supernova discovered in , this brilliant newcomer to the southern sky gave astronomers their first opportunity to study the death of a relatively nearby star with modern instruments.

It was also the first time astronomers had observed a star before it became a supernova. The star that blew up had been included in earlier surveys of the Large Magellanic Cloud, and as a result, we know the star was a blue supergiant just before the explosion. By combining theory and observations at many different wavelengths, astronomers have reconstructed the life story of the star that became SN A. Formed about 10 million years ago, it originally had a mass of about 20 M Sun.

At this time, its luminosity was about 60, times that of the Sun L Sun , and its spectral type was O. When the hydrogen in the center of the star was exhausted, the core contracted and ultimately became hot enough to fuse helium. By this time, the star was a red supergiant, emitting about , times more energy than the Sun. While in this stage, the star lost some of its mass.

This lost material has actually been detected by observations with the Hubble Space Telescope Figure 4. The gas driven out into space by the subsequent supernova explosion is currently colliding with the material the star left behind when it was a red giant. As the two collide, we see a glowing ring.

Figure 4: Ring around Supernova A. These two images show a ring of gas expelled about 30, years ago when the star that exploded in was a red giant. The supernova, which has been artificially dimmed, is located at the center of the ring. The left-hand image was taken in and the right-hand image in Note that the number of bright spots has increased from 1 to more than 15 over this time interval. But if a star is more than about eight times as massive as our sun, it can go on to forge even heavier elements.

All that weight on the core keeps the pressure and temperature extremely high. The star forges heavier and heavier elements until iron is created. Iron is not a stellar fuel. In fact, iron saps energy from its surroundings. Without an energy source to fight against gravity, the bulk of the star now comes crashing down on its core. That core collapses on itself until it becomes a ball of neutrons. That ball can survive as a neutron star — a hot orb now only about the size of a city.

But if enough gas from the dying star rains down on the core, the neutron star loses its own battle with gravity. What results is a black hole. Before that happens, the initial onrush of gas from the rest of the star hits the core and bounces back outward. This sends a shock wave back toward the surface, which tears the star apart.

The ensuing explosion can forge elements even heavier than iron. More than half of the periodic table of elements may have been formed by supernovas. Neutrinos are too. These nearly massless subatomic particles barely interact with matter. Despite their ghostly nature, neutrinos are suspected of being the main driving force behind the supernova.

They are thought to inject energy into the developing shock wave. A lot of energy. They may, in fact, account for 99 percent of the energy released in such an explosion.

Neutrinos can pass through the bulk of the star unimpeded. That means they can get a head start out of the star, eventually arriving at Earth before the blast of light. Confirmation of this prediction was one of the big successes from A. Three neutrino detectors on different continents registered a nearly simultaneous uptick in neutrinos roughly three hours before Shelton recorded the flash of light.

A detector in Japan counted 12 neutrinos. Another in Ohio detected eight. A facility in Russia detected five more. In all, 25 neutrinos turned up. That counts as a deluge in neutrino science. Before A, astronomers thought that only puffy red stars known as red supergiants would end their lives in a supernova. These are gargantuan stars. One nearby example: the bright star Betelgeuse in the constellation Orion. It is at least as wide as the orbit of Mars. But the star that exploded as A had been a blue supergiant.

More surprises emerged after the launch of the Hubble Space Telescope three years later. Its early images were fuzzy. Once corrective optics were installed in , unexpected details of the fading explosion came into focus. However, as the doomed star neared the end of its life, it evolved into a hot body and generated faster stellar winds that caused the slower material to pile up and form the concentric ring-like structures observed around the exploded star, ESA officials said.

They slowly faded over the first decade after the explosion, until the shock wave of the supernova slammed into the inner ring in , heating the gas to searing temperatures and generating strong X-ray emission," ESA officials said in the statement. Original article on Space. Join our Space Forums to keep talking space on the latest missions, night sky and more! Avila STScI.

Help spread the word. Send Sending Message sent Thank you for sharing. Help us spread the word. Get Involved. Sign Up.