New study finds stars in metal-rich galactic areas explode more violently

Mar 08, 2013 by Bob Yirka report
This is the remnant of a supernova. Credit: NASA/MPIA/Calar Alto Observatory, Oliver Krause et al.

(Phys.org) —A team of researchers working in China has found evidence to suggest that stars that exist in metal-rich galactic areas tend to explode more violently when they go supernova, than do stars that explode in less metal-rich areas. In their paper published in the journal Science, describing their research, the team details how after analyzing data from the remnants of 188 type 1a supernovas, they found that those stars that existed in metal-rich areas and maybe in younger systems, tended to produce more violent explosions and associated diverse spectral features.

Scientists have come to believe that supernovas come about in a process that involves a white dwarf. But because a single white dwarf isn't large enough to set off an explosion, they believe a second star must be involved as well—either another white dwarf as a or via accretion of material by a companion star. Researchers can't tell using current methods which was involved when studying particular supernovas. In this new effort, the researchers believe they might have found a way to do so.

By studying and comparing the spectral features of 188 type 1a supernovas and the galactic geography of the area in which they exploded, the researchers discovered what they believe is a pattern that they claim hints at the nature of the that led to the explosion—those in metal-rich areas tended to produce more violent explosions. This suggest it's more likely that the more violent explosions are the result of a white dwarf pulling mass from a —one similar to our own, or perhaps a red giant—than the result of a binary white dwarf system exploding.

Understanding the nature of is critical to understanding the universe in general, as they are used to measure distances between objects—such measurements have led to the discovery that the universe is expanding, for example. For that reason, it would be helpful to know which sorts of stars lead to their creation and why they behave the way they do when they explode. This new research appears to be one more step in that direction.

Explore further: Chandra X-ray Observatory finds planet that makes star act deceptively old

More information: Evidence for Two Distinct Populations of Type Ia Supernovae, Science DOI: 10.1126/science.1231502

ABSTRACT
Type Ia supernovae (SNe Ia) have been used as excellent standardizable candles for measuring cosmic expansion, but their progenitors are still elusive. Here, we report that the spectral diversity of SNe Ia is tied to their birthplace environments. We find that those with high-velocity ejecta are substantially more concentrated in the inner and brighter regions of their host galaxies than are normal-velocity SNe Ia. Furthermore, the former tend to inhabit larger and more-luminous hosts. These results suggest that high-velocity SNe Ia likely originate from relatively younger and more metal-rich progenitors than normal-velocity SNe Ia, and are restricted to galaxies with substantial chemical evolution.

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Q-Star
5 / 5 (4) Mar 08, 2013
Scientists have come to believe that supernovas come about in a process that involves a white dwarf.


That should actually be Type I supernovae. All supernovas{sic} are not created equal.
rubberman
5 / 5 (2) Mar 08, 2013
Scientists have come to believe that supernovas come about in a process that involves a white dwarf.


That should actually be Type I supernovae. All supernovas{sic} are not created equal.


But what about the EM field that....BLAH, kidding Q. And I agree wholeheartedly, they are like snowflakes, no two can be exactly the same.
Q-Star
5 / 5 (1) Mar 08, 2013
Scientists have come to believe that supernovas come about in a process that involves a white dwarf.


That should actually be Type I supernovae. All supernovas{sic} are not created equal.


But what about the EM field that....BLAH, kidding Q. And I agree wholeheartedly, they are like snowflakes, no two can be exactly the same.


I was referring to the fact that Type II supernovae are thought to come from stellar collapse that doesn't involve white dwarfs. (And the misspelling of supernovae.)
Lurker2358
2.3 / 5 (3) Mar 08, 2013
If stars smaller than white dwarfs (not Neutron Stars or BH,) are ever found, they should probably be called Pixies, or Gnomes.

There are also hypothetical quark stars and strangelets and such. I wonder what those would look like in a telescope compared to the normal stars we know?
katesisco
1 / 5 (3) Mar 08, 2013
I theorize that 'pure gas' stars are tightly wound magnetically, low luminosity as not much energy leaks past the magnetic wrap. The pure gas wrapping allowed a 'centering' that keeps the balance perfect. Remember the Methuselah star a couple hundred light year from us first thought to be older than the Universe? The science site said it was because it was not polluted! Polluted by heavy metals of course.
Fleetfoot
5 / 5 (2) Mar 10, 2013
Two weeks ago, Phys.org also published this.

"A white dwarf explodes when its nuclear furnace reignites. This occurs when a white dwarf tugs material from a nearby star. ... Fusion reignites and the white dwarf explodes. That explosion is a Type 1a supernova. "We call these Type 1a supernovae standard candles," Ferrante said. ... While Sherpa is a standard Type 1a, Everest is peculiar. It exhibits the characteristics of a Type 1a called a 1991T, Ferrante said. "Everest is the result of two white dwarfs that collide, then merge," he said.


Apparently, two weeks ago they could tell the difference but now they can't.

http://phys.org/n...ion.html