A Story of 1800 Exploding Stars

The Subaru Telescope recorded 1,800 supernova events throughout the Universe in a new study, demonstrating the unparalleled capabilities of this unique telescope. Between 2016 and 2017, astronomers using the observatory imaged fields of stars over a period of four to six months, allowing them to see stars flare up during explosive eruptions.

When supernova explode, they can outshine billions of stars in their home galaxies before fading away.

“[T]he team identified 5 super luminous supernovae, and about 400 Type Ia supernovae. Fifty-eight of these Type Ia supernovae were located more than 8 billion light years away from Earth. In comparison, it took researchers using the Hubble Space Telescope about 10 years to discover a total of 50 supernovae located more than 8 billion light years away from Earth,” The Kavli Institute for the Physics and Mathematics of the Universe reports.


You’re a Star — Have a Blast!

Supernovae (the plural of supernova) result from two major processes, although a third variety is currently being studied, and other processes may also result in such explosions. The first of these, type I supernovae, are found in binary star systems, as material falls from a larger star onto a smaller companion. Once the material reaches a critical mass, a tremendous explosion erupts, destroying the star, releasing it’s companion to fly free in space.

The most familiar variety of supernova, designated type II, is the explosive destruction of a massive star as it dies.

The Hubble Space Telescope recorded the light echo of supernova SN 2014J, found in the galaxy M82, 11.4 million light-years from Earth. Credit: NASA Goddard

Super luminous supernovae are the newest variety of supernova discovered by astronomers, and are the least understood. While Type I supernovae can flash with a luminosity of a few billion times the brightness of the Sun, super luminous events can be five to 10 times greater than that impressive display. Their great luminosity allows astronomers to see these events at extreme distances, viewing supernovae from the earliest days of stars and galaxies in the Universe.


Just Keep Staring. You’ll See it.

This new study carefully examined 1,824 potential supernova events, finding 433 were type 1a supernovae. This finding doubles the number of supernova ever found at such enormous distances.

Type 1a supernovae ignite when the gas which fell from the larger companion reaches a critical density, causing the material to erupt with a specific amount of energy. Their consistent maximum brightness allows astronomers to use them as reliable “standard candles” to measure the distance to far-flung galaxies. This measurement makes it possible to calculate the expansion rate of the Universe.

“Although many supernovae have been seen in nearby galaxies, supernova explosions are relatively rare events in our own galaxy, happening once a century or so on average. The last nearby supernova explosion occurred in 1680… Before 1680, the two most recent supernova explosions were observed by the great astronomers Tycho Brahe and Johannes Kepler in 1572 and 1604 respectively,” NASA explains in Imagine the Universe.


I Can See Clearly Now…

The location of the supernovae (red) discovered by astronomers taking part in this new study. The blue circles represent individual fields seen during the study, and an image of the Moon is placed for scale. Image credit: Sloan Digital Sky Survey/Kavli IPMU/Partial data supplied by: SDSS

Only a handful of telescopes in (and above) the Earth, including the Subaru Telescope, are powerful enough to capture sharp images of distant stars. Paired with the 870-megapixel Hyper Suprime-Cam (HSC) camera, this instrument captures a much larger area of the sky at one time than is possible with other large telescopes.

The Subaru Telescope, together with the HSC, records images measuring 1.77 degrees from side to side, nearly enough area to enclose 50 full Moons, packed like eggs in a carton. The camera is equipped with 104 charge-coupled devices (CCD’s), each able to resolve six mega-pixels of data. Operated by the National Astronomical Observatory of Japan, the instrument is located within the Mauna Kea Observatory on Hawaii.


A Connection Written in the Stars

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.”

― Carl Sagan, Cosmos

Supernovae are rare in our galaxy, only taking place roughly once every 100 years.

The closest supernova in the modern age took place in 1987, when a massive star located in the Large Magellanic Cloud (a satellite galaxy of the Milky Way) was seen exploding as a Type II supernova.

The death of a massive star in our own galactic neighborhood. Credit: Chandra X-ray Observatory

Every element in the Universe heavier than iron on the periodic table is produced in the eruptions of Type II supernovae, including atoms which make up plants, animals, and human beings. Watching these distant, ancient supernova explosions, we may be glimpsing elemental seeds being spread to the Universe which gave rise to life on distant worlds. Those elements, now temporarily collected as intelligent beings, might even be looking back at us at this very moment.

The Cosmic Companion

Exploring the wonders of the Cosmos, one mystery at a time

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James Maynard is the author of two books, and thousands of articles about space and science. E-mail: thecosmiccompanion@gmail.com

The Cosmic Companion

Exploring the wonders of the Cosmos, one mystery at a time