#type ii supernova

[zespaceblog]

SN 2023ixf

Supernova are incredibly rare, from time to time we spot a distant one, but when we get one in a nearby galaxy or even our own, it's incredibly exciting for astronomers.

The last observed supernova in the Milky Way was in 1604, known as Kepler's supernova, which occurred 20,000 light years from Earth and got as bright as mag -2.5, it would have been the brightest star in the sky by some way (Sirius being -1.3), it is thought there may have been a few more since, but that they failed to become bright enough to the human eye having been concealed by dust and gas. It is thought this was a type 1A supernova.

SN1604 remnants

SN1987A occurred 150,000 light years from Earth but not in our Milky Way, but it's companion galaxy the Large Magellanic Clouds. Unlike SN1604, it was a type 2 supernova, a huge star that had collapsed having built up iron at it's core that it couldn't fuse, and when fusion energy stops pushing outwards, gravity wins ! The star collapsed.

Type 1 supernova come in a variety of flavours and are particularly interesting because they tend (Although not always) to explode with the same light output, allowing us to use these explosions to then predict the actual distance, or what we call Standard Candles in Astronomy.

SN2023ixf was similar to the SN1987a, a type 2 but at 20.87 million light years from Earth, it's close enough for us to observe. Much of those observations, especially in the past, were based on Radio output, and that should be useful in this new supernova, but many type 1a supernova's don't output much in the way of radio waves, and that's because of the way they occur.

Unlike type II. type 1a's occur in a tight binary partnership. One of the stars, maybe similar size to our Sun has died and become a white dwarf. Eventually it's companion also enters it's old age, expands and the white dwarf now starts pulling in huge amounts of hydrogen from the star's atmosphere, and increasing in mass.

Once it hits the Chandrasekhar limit of around 1.4 times the mass of our Sun, the weight of the white dwarf begins a second collapse, and goes supernova as it becomes a neutron star, often ejecting the old companion into space.

This is why many Type 1a supernova have similar brightness, because they explode only when they reach a point of collapse.

Credits for the title images go to @OkanaganAstro on Twitter who posted them when first spotted.

Other sources

Not All Type 1a Supernovae are Created Equally

New research shows that there are variations in how white dwarfs explode.

[startswithabang]

These Are The 6 Different Ways To Make A Supernova

“Yet, if you cross a certain mass threshold, you overcome that quantum barrier, and that triggers a runaway fusion reaction, destroying the white dwarfs and leading to a different class of supernova: a thermal runaway supernova.

So, we've got core collapse supernovae and thermal runaway supernovae. Does that mean that there are only two classes?

Hardly. There's more than one way to make both a thermal runaway and a core collapse supernova, and each mechanism or method has properties that are wholly unique to it. Here are the six ways to make a supernova, starting with the least-massive trigger and going up from there.”

So, you’ve got a star, and you want to trigger a supernova with it? Great! Every star that ever gets made in the Universe has the possibility of going supernova. If your star is born with more than about 8 solar masses, it’s practically an inevitability that a supernova will ensue, and that it will be a core-collapse supernova at that. But there are four independent ways to make that happen, and only one of them is the conventional way you probably think about it. If your star has less than 8 solar masses, though, it ends its life in a white dwarf, but that’s not necessarily the end. White dwarfs can gain enough mass, through two different known mechanisms, to someday go supernova as well.

There are six different ways to make a supernova, and each one is spectacular. Which one is your favorite?

[eartharchives]

Iron found in fossils suggests supernova role in mass dying

Outer space touches us in so many ways; including cataclysmic Type II Supernovae

[astronomyjourney-blog]

TYPE II SUPERNOVAE

High mass stars can proceed past carbon fusion. Gravity continues to crush the compact carbon core until it continues rapidly fusing all the elements until it reaches iron.The inner iron core, however, can collapse and begin a type II supernova.

Because there is no fusion to support the star, the entire star implodes into itself. The outer layer of the star contracts into the inner core and causes a collision between the two layers. This collision creates the conditions for the most massive elements.

firstly, the temperature rises to surpass that of even the highest mass stars, creating highly reactive neutrons.

secondly, the shock wave of the explosion that follows the collapse compresses material as it passes through into heavier elements.

CONTINUE YOUR JOURNEY↠

[wigmund]

From Earth Science Picture Of The Day; February 10, 2014:

Newly Discovered Supernovas in NGC 3448 and M82 Photographers and Summary Authors: (Top Image) Patrick Wiggins; (Bottom Image) Kosmas Gazeas

Top Image: In mid January I was lucky enough to discover a supernova -- SN 2014G. The G indicates it’s the seventh supernova discovered in 2014. It was found in galaxy NGC 3448 while observing from my home observatory near Salt Lake City. The pre-discovery image I used to compare with the SN 2014G image was acquired on January 6, 2014. The actual date of the discovery was January 14, 2014 at 07:36:02 UT, when a nearly full Moon brightened the sky. NGC 3448 is about 78 million light years away in the direction of the constellation Ursa Major. Light from this Type II supernova explosion that’s just reaching Earth now started its journey when dinosaurs roamed the Earth. This supernova is far too faint to be seen with the naked eye -- a fairly large telescope must be used.

Bottom Image: Shown at bottom is a Type Ia supernova (SN 2014J) that was also discovered in mid January in the direction of Ursa Major, but this exploded star is in the Cigar Galaxy (M82), some 12 million light years distant. Its discoverer is Steve Fossey of University College London. SN 2014J is evidently nearer to us than any other Type Ia supernova sighted in the past 42 years. Though this supernova is relatively nearby, it can't be seen with the unaided eye.

[joerosewood]

Stars with at least nine solar masses of material evolve in a complex fashion.[62] In the core of the star, hydrogen is fused into helium and the thermal energy released creates an outward pressure, which maintains the core in hydrostatic equilibrium and prevents collapse.

When the core's supply of hydrogen is exhausted, this outward pressure is no longer created. The core begins to collapse, causing a rise in temperature and pressure which becomes great enough to ignite the helium and start a helium-to-carbon fusion cycle, creating sufficient outward pressure to halt the collapse. The core expands and cools slightly, with a hydrogen-fusion outer layer, and a hotter, higher pressure, helium-fusion center. (Other elements such as magnesium, sulfur and calcium are also created and in some cases burned in these further reactions.)

This process repeats several times; each time the core collapses, and the collapse is halted by the ignition of a further process involving more massive nuclei and higher temperatures and pressures. Each layer is prevented from collapse by the heat and outward pressure of the fusion process in the next layer inward; each layer also burns hotter and quicker than the previous one—the final burn of silicon to iron consumes its fuel in just a few days at most.[63] The star becomes layered like an onion, with the burning of more easily fused elements occurring in larger shells