Posted on 03/26/2013 3:17:46 PM PDT by LibWhacker
This artist's conception shows the suspected progenitor of a new kind of supernova called Type Iax. Material from a hot, blue helium star at right is funneling toward a carbon/oxygen white dwarf star at left, which is embedded in an accretion disk. In many cases the white dwarf survives the subsequent explosion. Credit: Christine Pulliam (CfA)
(Phys.org) —Supernovae were always thought to occur in two main varieties. But a team of astronomers including Carnegie's Wendy Freedman, Mark Phillips and Eric Persson is reporting the discovery of a new type of supernova called Type Iax.
This research has been accepted for publication in The Astrophysical Journal and is available online.
Previously, supernovae were divided into either core-collapse or Type Ia categories. Core-collapse supernovae are the explosion of a star about 10 to 100 times as massive as our sun. Type Ia supernovae are the complete disruption of a tiny white dwarf.
This new type, Iax, is fainter and less energetic than Type Ia. Although both types come from exploding white dwarfs, Type Iax supernovas may not completely destroy the white dwarf.
"A Type Iax supernova is essentially a mini supernova," says lead author Ryan Foley, Clay Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). "It's the runt of the supernova litter."
The research team—which also included Max Stritzinger, formerly of Carnegie—identified 25 examples of the new type of supernova. None of them appeared in elliptical galaxies, which are filled with old stars. This suggests that Type Iax supernovas come from young star systems.
Based on a variety of observational data, the team concluded that a Type Iax supernova comes from a binary star system containing a white dwarf and a companion star that has lost its outer hydrogen, leaving it helium dominated. The white dwarf collects helium from the normal star.
Researchers aren't sure what triggers a Type Iax. It's possible that the outer helium layer ignites first, sending a shock wave into the white dwarf. Alternatively, the white dwarf might ignite first due to the influence of the overlying helium shell.
Either way, it appears that in many cases the white dwarf survives the explosion, unlike in a Type Ia supernova where the white dwarf is completely destroyed.
The team calculates that Type Iax supernovae are about a third as common as Type Ia supernovae. The reason so few have been detected is that the faintest are only one-hundredth as bright as a Type Ia supernova.
"The closer we look, the more ways we find for stars to explode," Phillips said. The Large Synoptic Survey Telescope could discover thousands of Type Iax supernovas over its lifetime.
Journal reference: Astrophysical Journal 
Provided by Carnegie Institution for Science
cool, very interesting. thanks
Smash hydrogenonormity!
*ping*
aka the “Super-duperNova”
Thanks fieldmarshaldj, a four-list pingworthy topic if ever there was one.
Thanks fieldmarshaldj.
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Thanks fieldmarshaldj.
A champagne supernova?
None of them appeared in elliptical galaxies, which are filled with old stars. This suggests that Type Iax supernovas come from young star systems.
Somebody help me out here. Wouldn’t a carbon/oxygen white dwarf star be a second generation star? Are second generation stars consistent with young systems?
Can’t all these supernova’s just get along?
I thought caastrophism only involved us Humans?
I believe you are right. If I understand things correctly, elements of the periodic table, up to and including carbon, can be created in stars. No problem. Elements heavier than that, of which oxygen is one, can only be created in a supernova. But as you seem to suspect, a “young” system need not be a first generation system; i.e., ‘young’ in this context only means the star in question formed recently. The cloud of gas and dust, out of which it formed, may have contained heavy elements that were thrown out by an older supernova.
Cool!
Hey, I had raw broccoli for lunch, okay? ;’)
Not sure, but I think it’s possible for a star to start fusing helium into carbon & oxygen when it runs out of hydrogen.
Is it “gay?” (Seems like everything else is....)
Another thing that bothers me, isn't the plural of nova novae? Sorry, I took Greek rather than Latin, so I can't say for sure. Maybe I remember the spelling from my epoch 1970 Nortons.
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