What is metal-poor star?
What is metal-poor star?
Metal-poor stars that are observable today are PopulationII objects and belong to the stellar generations that formed from non-zero metallicity gas. In their atmospheres these objects preserve informa- tion about the chemical composition of their birth cloud.
Where are metal-poor stars found?
the galactic halo
One long-standing issue concerns metal-poor stars found in the galactic halo. These sparse stars surround the galaxy’s spiral disk and formed a long time ago from nearly pristine gas that was barely touched by earlier generations of stars.
Are metal-rich stars brighter?
i.e. High metallicity stars have a lower luminosity than more metal-poor stars of the same mass. As the fuel supply is dominated by hydrogen, and as a mass fraction this is very similar in both metal-rich and metal-poor stars, then the lifetimes of metal-rich stars are longer.
How are metals made in stars?
Stars create new elements in their cores by squeezing elements together in a process called nuclear fusion. First, stars fuse hydrogen atoms into helium. Helium atoms then fuse to create beryllium, and so on, until fusion in the star’s core has created every element up to iron.
Is the Sun metal poor?
The Sun is considered Population I, a recent star with a relatively high 1.4 percent metallicity. Note that astrophysics nomenclature considers any element heavier than helium to be a “metal”, including chemical non-metals such as oxygen.
Which star population is very old and is metal poor?
Extreme Population II stars
They are relatively old stars, with ages ranging from 2 – 14 billion years. Extreme Population II stars (the most metal poor) are found in the halo and the globular clusters; these are the oldest stars.
Are all metals made in stars?
Answer: Virtually all of the elements we see on the Periodic Table were made at some point during the life and death of a star. Only hydrogen, helium, and lithium were created in a different way, i.e., they were created as a result of the Big Bang explosion.
Why are metal rich stars redder?
We discussed this before: if the atmosphere of a star contains more metals, then the dust and the gas will scatter preferentially the blue light hence the stars appears redder.
Why are metal-rich stars redder?
Do stars contain metals?
Very old stars which formed from the almost pristine material of the Big Bang contain almost no metals, while later generations of stars can have up to 5% of their mass in the form of metals. The percentage of metals in the Sun is approximately 2%, indicating that it is a later generation star.
Which population of star is metal-rich?
Population I stars
Population I stars are metal rich stars; they contain about 2-3 percent metals. They are found in the disk of the Galaxy.
Why are newer stars metal-rich while older stars are metal-poor?
Formation of the observable stars The oldest observed stars, known as Population II, have very low metallicities; as subsequent generations of stars were born they became more metal-enriched, as the gaseous clouds from which they formed received the metal-rich dust manufactured by previous generations.
Which is more metal poor the sun or the star?
A value of $[Fe/H]=-1$ means our sun has an iron to hydrogen ratio that is 10 times greater than the given star’s, for example. The more negative this value, the more metal-poor the star is (or, at least, iron poor) than our own sun, which is considered of a fairly recent generation.
What makes a star a metal rich star?
metal-rich star. [′med·əl ¦rich ′stär] (astronomy) A star in which the ratio of metals (elements heavier than helium) to hydrogen is greater than that of the Hyades.
What kind of stars have high mass of iron?
Iron, built up in massive stars and also later in Type Ia (white dwarf) supernovae: prompt and delayed release after stars are formed, involve high and low mass stars Alphas, built up in massive stars: prompt release, high mass stars
