A New Type of Supernova Unlocks Thousand-Year-Old Stellar Mysteries

Around July 4, 1054, Chinese astronomers recorded a “guest star” that shone so brightly, it was visible in broad daylight for 23 days. The remnants of that long-ago supernova now form the Crab Nebula, which has long been of great interest to astronomers. Some have hypothesized that SN 1054 (as it is now known) was a new, rare type of supernova first described by a physicist some 40 years ago. A team of astronomers has now identified a second recent supernova—dubbed SN 2018zd—that meets all the criteria for this new type, according to a new paper published in the journal Nature Astronomy, thereby providing a vital missing link in our knowledge of stellar evolution.

click here for more info
investigate this site
more helpful hints
read
over at this website
find
go to the website
try this site
look at more info
look what i found
Full Report
websites
Extra resources
get more
like it
click here for more
find out here now
this hyperlink
home
site here
discover here
click here for info
try this website
go
look at here
Visit Your URL
see this website
visit this page
Click Here
check this
browse around these guys
redirected here
visit this site right here
review
have a peek at this website
right here
why not try this out
article source
visite site
web link
you could try this out
description
my latest blog post
find out this here
wikipedia reference
find more information
continue reading this
this post
index
official website
go to these guys
learn the facts here now
Related Site
Click This Link
Visit This Link
you can try here
linked here
visit homepage
web
YOURURL.com
you can find out more
see this site
additional resources
Website
pop over to this site
view it now
their website
special info
you could try these out
site
Check Out Your URL
my explanation
helpful site
More Info
go right here
this article
visit their website
check out here
he said
official source

“The term ‘Rosetta Stone’ is used too often as an analogy when we find a new astrophysical object, but in this case I think it is fitting,” said coauthor Andrew Howell of Las Cumbres Observatory (LCO). “This supernova is literally helping us decode thousand-year-old records from cultures all over the world. And it is helping us associate one thing we don’t fully understand, the Crab Nebula, with another thing we have incredible modern records of, this supernova. In the process it is teaching us about fundamental physics: how some neutron stars get made, how extreme stars live and die, and about how the elements we’re made of get created and scattered around the universe.”

There are two types of known supernova, depending on the mass of the original star. An iron-core-collapse supernova occurs with massive stars (greater than 10 solar masses), which collapse so violently that it causes a huge, catastrophic explosion. The temperatures and pressures become so high that the carbon in the star’s core begins to fuse. This halts the core’s collapse, at least temporarily, and this process continues, over and over, with progressively heavier atomic nuclei. (Most of the heavy elements in the periodic table were born in the intense furnaces of exploding supernovas that were once massive stars.) When the fuel finally runs out entirely, the (by then) iron core collapses into a black hole or a neutron star.

Then there is a thermonuclear supernova. Smaller stars (up to about eight solar masses) gradually cool to become dense cores of ash known as white dwarfs. If a white dwarf that has run out of nuclear fuel is part of a binary system, it can siphon off matter from its partner, adding to its mass until its core reaches high enough temperatures for carbon fusion to occur.

In 1980, Japanese physicist Ken’ichi Nomoto of the University of Tokyo theorized that there could be a third intermediate type: a so-called “electron-capture” supernova, in which a star isn’t heavy enough to produce an iron-core-collapse supernova, and yet is not light enough to prevent its core from collapsing entirely. Instead, such stars stop the fusion process when their cores are composed of oxygen, neon, and magnesium. In this scenario, electrons get gobbled up by the neon and magnesium in the core, thereby causing the core to buckle under its own weight. The end result is a supernova.

Since Nomoto first proposed electron-capture supernovas, theorists have built on his work to identify six key features: the stars should have a lot of mass; they should lose much of that mass before exploding; that mass should have an unusual chemical composition; the resulting supernova should be weak; there should be little radioactive fallout; and the core should contain neutron-rich elements.

Leave a Reply

Your email address will not be published. Required fields are marked *