A conjecture: Supernova - The Induced Chain Contraction

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A conjecture: Supernova - The Induced Chain Contraction

文章 每天update » 週日 02 3月, 2014 23:34

(發表的只是個人意見, 猜測)
composed by 每天update

link: NuSTAR telescope takes first peek into core of supernova, http://phys.org/news/2014-02-nustar-tel ... rnova.html

Supernova - The Induced Chain Contraction

In the picture, and other pictures for the composition of the core of supernovae in wikepedia.org, suppose the radius of star=r and roughly radius of Fe core =0.1r.
Layperson's view, I think the discontinuous output of the radiation-pressure is rather the main reason for the speedy collapse of the **outer shell** of supernovae. The radiation pressure against gravity maintains the balance of stars.

My conjecture is that {
once the fuel of a star is insufficient, the Fe core is the "first"/earliest part to respond/react to it. The Fe core is the most pressurised part not only due to its location, but also due to iron's atomic weight and gaseous/fluid density. Radiation energy is supposedly to radiate outwardly measuring from the center of star. The iron core never has fusion which produces no energy. Where fusions generating energy are the onion shells next to the core such as the shells of Si, O, C . . . etc. It is realised that the radiation energy is the largest near the center of star.

When star begins to collapse, that is, radiation pressure is low. The Fe core is the first to respond to the event because the Fe "core" is near the "center", and it sustains the weight of the whole star. And this effect of low radiation pressure continues to propagate throughout the rest parts of the star. The speed of falling into the center no doubt the Fe core is the fastest. While Fe core falling towards the center, the outer shells of the star should experience/measure the same gravitational force as before. The mass enclosed in the sphere of Gauss with radius=0.1r remains the same(within some short period). The shrunk core, and the Fe core before the contraction, exert exactly the same gravity to the outer shells (at short time only). When the core shrinks, the outer shells (within short period of time) do not accelerate toward the center too fast as the initial velocities are approximately zero.

The shrinking core creates a (relatively) low pressure shell/region and surrounded by this (relatively) low pressure shell. With the core enclosed by this low pressure shell, the particles/gases of outer shells with Maxwell's gaseous speed would not be too slow moving towards center no matter whether they are ideal gas or not.

What interesting is, during the contraction of the core, probably the fusions of lighter elements are continuing, providing the continued radiation pressure to slowing down the contraction of outer shells. But what really interesting is, when the said low pressure shell spreads outward. This (relatively) low pressure shell/region must shutdown all reaction centers on its path, because one of the conditions for fusion altered - sufficiently high pressure. What dramatically interesting is, with this low pressure feature, while the outer shells are sucked toward center, the temperature of these gases also drops sharply, an unexpected discovery. It dissatisfies another condition for fusion - enough high temperature.

The further problem is that these fusion reaction centers at outer shells stop output radiation pressure. They (fusion reaction centers next to the core and other outer shells, e.g. the shells of Si, oxygen) are also shrinking themself - an induced contraction by the travelling low pressure shell. Well, thinking along these logic, it is surprisingly to discover that not only the iron core collapse, the rest of the star next to the core shrink by themselves too.

The conclusion of my conjecture is:
-(1) the iron core shrinks because of large gravitational force;
-(2) a (relatively) low pressure shell/region travels outward from the iron center;
-(3) along the path of the travelling low pressure shell:
(3a) pressure drops;
(3b) local fusion reaction center shutdown therefore supplying of radiation pressure stops;
(3c) temperature drops;
(3d) contraction induced locally;
(3e) the (3d), this induced contraction may be called **induced chain contraction** which deteriorates the fusion of the whole star and exponentially speeds up the collapsing of the entire star.

Logically, it is generally realised that the iron core shrinks because of large gravitational force. With this thought experiment it is surprised to discover that the outer shells and the entire star perhaps collapse much fast than expected with the **induced chain contraction**.

These only are personal view of a layperson.
Supernova - The Induced Chain Contraction
<> end of the conjecture <>.

Picture Credit: wikipedia.org

composed by 每天update
hkastroforum.net 2014.3.2

文章: 9497
註冊時間: 週一 03 8月, 2009 17:15
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文章 鄧登凳 » 週一 03 3月, 2014 19:01

Read http://www.astro.umd.edu/~miller/teachi ... ture20.pdf to have some understanding of the collapse of a massive star. :)


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