What are the characteristics and location of population I stars? of population I

Question

What are the characteristics and location of population I stars? of population II stars? b All stars in the Milky Way have some heavy elements in them -none seem to be composed of only hydrogen and helium. Stars composed of only hydrogen and helium should have formed very early in the galaxy. How do astronomers explain the complete lack of these population III stars? 2. 7-7 The characteristics of the population I stars include the sun and they tend to be luminous, hot and 8 young They are located or concentrated in the disks of spiral galaxies. They are particularly 8 found in the spiral galaxies. With the model of heavy element formation in supernovae, this suggests that the gas from which they formed had been seeded with the heavy elements formed from previous giant stars. About 2% of the total belong to Population I. However, the Population II stars are characterized by being older, less luminous and cooler than Population I stars. They have fewer heavy elements, either by being older or being in regions where no heavy-element producing predecessors would be found. Astronomers often describe this condition by saying that they are "metal poor", and the "metallicity" is used as an indication of age.

Explanation / Answer

The various explains the lack of Pop III stars:
1. Pop III might have consumed their fuel long ago and they may be showing as white dwarfs, neutron stars or black holes, and its original composition is almost impossible to determine.
2. Another explanation is given as the stars sweep up gas from the interstellar medium and as they move through it this may be laid to the contamination of the outer layer of Pop III stars this could give Pop III stars an appearance of metal-poor Pop II stars.
3. The metal produced in the core of the Pop III stars have been dredged up to the surface of convection this caused in the self-contaminated stars can be misclassified as metal-poor Pop II stars.
4. Pop III stars are high mass stars, in the range of 60-300 times that of the sun, this strongly suggests that all the Pop III stars would have exhausted their fuel long ago and they are present in the form of remnants in our universe.
Whatever might be the cause it’s most unlikely we will ever observe Pop III star and it will remain a hypothetical entity.

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