S. Bilderback wrote:
Higher mass density, yes. More mass, no. There is an upper pressure/density limit a star can reach before fission starts. Any matter not under the pressure threshold will be blown out as solar wind.
That is correct for stars forming in primal hydrogen clouds - to a point.
Watch our clouds as they enter cold air. The steam molecules contract and pull the cloud apart into evenly sized puff balls.
Something like that must have happened as the first stars were formed. It is thought that Hydrogen condensed into spherical clouds which condensed into the first globular clusters, which condensed into smaller puff balls.
At some mass, each puff ball condensed to the point of ignition and became a separate star.
Some surmise early high cosmic temperatures required large puff balls and massive first stars. This is suggested by distant objects surrounded by massive clouds of iron dust.
The present microwave background is somewhere around 3 degrees K. At that temperature, hydrogen is a metallic solid.
One Stellar mass should be defined as the minimum mass required for hydrogen to be compressed into helium and ignite to become a star.
How many stellar masses = one Solar Mass?
Small stars only convert hydrogen into helium. Some say they can only produce 10-15% helium before shutting down and going quietly into that good night.
But this takes longer than the universe has existed.
Medium mass stars present a confusing picture because of the relative instability of various element structures. The material ejected tends to be surface material mixed with dredged up material, but there is a correlation to the periodic table (carbon, nitrogen, oxygen) with increasing star mass up through about 8 solar masses showing at least three dredge up episodes as they move off the main line sequence into the red giant branch. If heavier elements are formed, they are trapped in the collapsing core.
Companion stars add to the confusion and opinions.
Higher mass stars dredge up ever heavier elements, and the core spins faster and faster as it collapses into ever denser elements. Depending on the initial mass, the core finally compressed into a white dwarf, neutron star or black hole, and the material above the core is blasted out into space. This is the birthplace of our copper, silver and gold.
The literature (Bernard E. J. Pagel -
Nucleosynthesis and Chemical Evolution of Galaxies Page 201) speaks of stars of up to
120 Solar Masses, and speculate that at some upper value, they may collapse directly into black holes without ever emitting any light or material at all.
Small mass = long life. Medium mass = medium life. Maximum mass = no life at all.
Perhaps short lives explains why the outer edges of galaxies spin faster than expected.
S. Bilderback wrote:[quote]Higher mass density, yes. More mass, no. There is an upper pressure/density limit a star can reach before fission starts. Any matter not under the pressure threshold will be blown out as solar wind.[/quote]
That is correct for stars forming in primal hydrogen clouds - to a point.
Watch our clouds as they enter cold air. The steam molecules contract and pull the cloud apart into evenly sized puff balls.
Something like that must have happened as the first stars were formed. It is thought that Hydrogen condensed into spherical clouds which condensed into the first globular clusters, which condensed into smaller puff balls.
At some mass, each puff ball condensed to the point of ignition and became a separate star.
Some surmise early high cosmic temperatures required large puff balls and massive first stars. This is suggested by distant objects surrounded by massive clouds of iron dust.
The present microwave background is somewhere around 3 degrees K. At that temperature, hydrogen is a metallic solid.
[b][color=darkred]One Stellar mass[/color] [/b]should be defined as the minimum mass required for hydrogen to be compressed into helium and ignite to become a star.
[b]How many stellar masses = one Solar Mass?[/b]
[b]Small stars[/b] only convert hydrogen into helium. Some say they can only produce 10-15% helium before shutting down and going quietly into that good night. [b]But[/b] this takes longer than the universe has existed.
[b]Medium mass stars[/b] present a confusing picture because of the relative instability of various element structures. The material ejected tends to be surface material mixed with dredged up material, but there is a correlation to the periodic table (carbon, nitrogen, oxygen) with increasing star mass up through about 8 solar masses showing at least three dredge up episodes as they move off the main line sequence into the red giant branch. If heavier elements are formed, they are trapped in the collapsing core.
[b]Companion stars[/b] add to the confusion and opinions.
[b]Higher mass stars[/b] dredge up ever heavier elements, and the core spins faster and faster as it collapses into ever denser elements. Depending on the initial mass, the core finally compressed into a white dwarf, neutron star or black hole, and the material above the core is blasted out into space. This is the birthplace of our copper, silver and gold.
The literature (Bernard E. J. Pagel - [i]Nucleosynthesis and Chemical Evolution of Galaxies[/i] Page 201) speaks of stars of up to [b]120 Solar Masses,[/b] and speculate that at some upper value, they may collapse directly into black holes without ever emitting any light or material at all.
Small mass = long life. Medium mass = medium life. Maximum mass = no life at all.
Perhaps short lives explains why the outer edges of galaxies spin faster than expected.