Massive Stars in NGC 6357 (APOD 09 Oct 2008)

[Boomer12k]

Stating that PISMIS 24 has stars with over 100 times the mass of the Sun. And knowing what generally happens to stars that massive, (i.e. Supernova, collapse to black hole etc...) is it just that the stars are so young and still has enough heat so as not to collapse yet?
Why doesn't that hugh of a mass not instantly crush?

Thanks.

[bystander]

http://apod.nasa.gov/apod/ap081009.html

It is my understanding that stars maintain their size by the energy produced from nuclear fusion. As long as the outward pressure from nuclear fusion is greater than the inward pressure of gravity the star does not collapse. When the nuclear fuel is exhausted, the star collapses under its own gravity.

http://en.wikipedia.org/wiki/Star#Forma ... _evolution

[neufer]

http://antwrp.gsfc.nasa.gov/apod/ap991207.html
http://antwrp.gsfc.nasa.gov/apod/ap061220.html
http://antwrp.gsfc.nasa.gov/apod/ap081009.html
http://antwrp.gsfc.nasa.gov/apod/ap061219.html

Stating that PISMIS 24 has stars with over 100 times the mass of the Sun. And knowing what generally happens to stars that massive, (i.e. Supernova, collapse to black hole etc...) is it just that the stars are so young and still has enough heat so as not to collapse yet?
Why doesn't that hugh of a mass not instantly crush?

Their problem is just the opposite!!

Such “hypergiants” are so luminous & tenuous that they can barely hold themselves together.

Supernova are heavy stars that are running low on fuel.
Hypergiants are heavy stars that are running low on gravity (so to speak).

• http://en.wikipedia.org/wiki/Hypergiants
  
  <<The word “hypergiant” is commonly used as a loose term for the most massive stars found, even though there are more precise definitions. In 1956, the astronomers Feast and Thackeray used the term super-supergiant (later changed into hypergiant) for stars with an absolute magnitude brighter than MV = -7. The most massive stars are considered to be hypergiants, and can have masses ranging up to 100-150 solar masses.
  
  Hypergiants are very luminous stars, up to millions of solar luminosities, and have temperatures varying widely between 3,500 K and 35,000 K. Almost all hypergiants exhibit variations in luminosity over time due to instabilities within their interiors.
  
  Because of their high masses, the lifetime of a hypergiant is very short in astronomical timescales, only a few million years compared to around 10 billion years for stars like the Sun. Because of this, hypergiants are extremely rare and only a handful are known today.
  
  As luminosity of stars increases exponentially with mass, the luminosity of hypergiants often lies very close to the Eddington limit which, simply put, is the luminosity where the gravitational pressure inwards equals the radiation pressure outwards. This means that the radiative flux passing through the photosphere of a hypergiant may be close to lifting off the photosphere. Above the Eddington limit, the star is supposed to generate so much radiation that parts of its outer layers are thrown off in massive outbursts, effectively restricting the star from shining at higher luminosities for longer periods.
  
  A consequence of passing the Eddington limit is thought to be the initiation of a continuum driven wind (from processes such as electron scattering, free-free and bound-free interaction), with extremely high mass loss rates up to 10 000 times stronger than the strongest line-driven stellar winds of sub-Eddington objects. As very few stars are thought to ever pass the Eddington limit, the continuum driven stellar winds are extremely rare and are mostly results of theoretical predictions.
  
  A good candidate for hosting a continuum driven wind is η Carinae , one of the most massive and luminous stars ever observed. However, even with a mass of around 130 solar masses and a luminosity four million times higher than the Sun, η Carinae is thought to only occasionally reach super-Eddington luminosities. The last time might have been a series of outbursts in 1840-1860, reaching mass loss rates much higher than any of the more well known stellar winds can explain.
  
  As opposed to line driven stellar winds, continuum driving does not require the presence of metallic atoms in the photosphere. This is important, since most massive stars also are very metal poor, which means that we need an effect that works independently of the metallicity. In the same line of reasoning, the continuum driving may also contribute to an upper mass limit even for the first generation of stars right after the Big Bang, which did not contain any metals at all.
  
  Another theory to explain the massive outbursts of for example η Carinae is the idea of a deeply situated hydrodynamic explosion, blasting off parts of the star’s outer layers. The idea is that the star even at luminosities below the Eddington limit would have insufficient heat convection in the inner layers, resulting in a density inversion potentially leading to a massive explosion. The theory has however not been explored very much, and it is uncertain whether this really can happen.>>