what is a population i star

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What are population I and Population II stars?

Populations I and II Stars. Stars may be classified by their heavy element abundance, which correlates with their age and the type of galaxy in which they are found. Population I stars include the sun and tend to be luminous, hot and young, concentrated in the disks of spiral galaxies. They are particularly found in the spiral arms.

What is the stellar population?

Stellar population. By definition, each population group shows the trend where decreasing metal content indicates increasing age of stars. Hence, the first stars in the universe (very low metal content) were deemed Population III, old stars (low metallicity) as Population II, and recent stars (high metallicity) as Population I.

What is an intermediate Population I star?

Population I stars are common in the Spiral arms of the Milky Way galaxy. Generally, the youngest stars are found further in, and intermediate population I stars are further out, etc. The Sun is considered an intermediate population I star. Population I stars have regular elliptical orbits of the galactic centre, with a low relative velocity.

What is population 1 of our galaxy?

(Population I is the name given to the stars found within the spiral arms of the Milky Way... Population I consists of younger stars, clusters, and associations— i.e., those that formed about 1,000,000 to 100,000,000 years ago.

What are population I and population II stars?

Astronomers have found that our galaxy has two general populations of stars. Population I stars are younger stars found in the disk of the galaxy that contain lots of atoms heavier than helium (metals). Population II stars are older, metal-poor stars found in a galaxy's nuclear bulge, halo, and globular clusters.

What are population 1 stars in the galaxy?

Population I stars Population I, or metal-rich, stars are young stars with the highest metallicity out of all three populations and are more commonly found in the spiral arms of the Milky Way galaxy.

Where are population I stars found?

Population I stars are metal rich stars; they contain about 2-3 percent metals. They are found in the disk of the Galaxy. They travel on circular orbits about the center of the Galaxy and generally remain in the plane of the Galaxy as they orbit.

What is a population 2 star?

Population II stars tend to be found in globular clusters and the nucleus of a galaxy. They tend to be 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.

What type of stars are population 1?

Population I consists of younger stars, clusters, and associations—i.e., those that formed about 1,000,000 to 1,000,000,000 years ago. Certain stars, such as the very hot blue-white O and B types (some of which are less than 1,000,000 years old), are designated as extreme Population I objects.

What are population 1 stars How do they differ from population 2 stars quizlet?

Population I stars are usually the blue younger stars. They orbit in the disk and they are relatively rich in metals. Population II stars are the red, older stars that lies in the bulge and halo of the Galaxy. They orbits in the elliptical orbits in the halo.

What color are Population II stars?

Baade designated as Population II the bright red giant stars that he discovered in the ellipticals and in the nucleus of Andromeda. Other objects that seemed to contain the brightest stars of this class were the globular clusters of the Galaxy.

What are the oldest known objects in the Milky Way?

A new study has focused on the spectra of NGC 6652 obtained by the Cerro Tololo Observatory and found that the globular cluster NGC 6652.4. 05957 is 13.6 billion years old. This makes the cluster one of the oldest objects in the Milky Way.

Where are population 2 stars located?

Population II stars are mainly found in the bulge and halo of galaxies.

What are Population II stars quizlet?

population II stars. stars poor in atoms heavier than helium ; relatively old stars nearly always found in the halo, globular clusters, or the central bulge. population I stars. stars with significant amounts of atoms heavier than helium; relatively young stars nearly always found in the galactic disk.

Why are Pop II stars always red?

The brightest stars in a group of Population II stars are red giants. Red giants are stars in the process of dying. They have run out of hydrogen fuel in the core and swollen into cool red giants typically the size of the Earth's orbit around the Sun.

Where are population 2 stars found in the Milky Way?

RR Lyrae variable stars and other Population II stars are found in the halos of spiral galaxies and in the globular clusters of the Milky Way system. Large numbers of these objects also occur in elliptical galaxies.

Where are population 2 stars located?

Population II stars are mainly found in the bulge and halo of galaxies.

What are Population II stars quizlet?

population II stars. stars poor in atoms heavier than helium ; relatively old stars nearly always found in the halo, globular clusters, or the central bulge. population I stars. stars with significant amounts of atoms heavier than helium; relatively young stars nearly always found in the galactic disk.

Where are the population I stars primarily located quizlet?

Population I stars include the sun and tend to be luminous, hot and young, concentrated in the disks of spiral galaxies. They are particularly found in the spiral arms.

Where are population 1 stars located?

Population I stars are young stars confined to the disk of the galaxy and of metal abundances near the solar value;

What is population synthesis?

Population synthesis is the attempt to reproduce the observed spectral energy distributions of galaxies by the summation of spectra of well-observed galactic stars, model stars, and models for the emission from the gas photoionized by hot stars in the synthesis. An important parameter in such studies is the Initial Mass Function (IMF), which is the differential distribution of stars as a function of mass in star forming regions. The simplest approximation for the IMF is a powerlaw in the mass, M,

What are the integrated spectra of galaxies?

The observed integrated spectra of normal galaxies are functions of stellar population, star formation rate, mean metal content, gas content, and dust content. These properties correlate with, and in some cases are causually related to, galaxy morphology. In our own galaxy there are two relatively distinct populations of stars as discovered by Baade in 1944. Population II stars are the old metal poor stars that form the halo of the galaxy. Globular clusters are population II objects. Population I stars are younger and more metal rich. They form the disk of the galaxy. The sun is an intermediate age population I star.

What do brackets around species mean?

Brackets around species indicate that the transition is forbidden.

Stars, Variable

Steven N. Shore, in Encyclopedia of Physical Science and Technology (Third Edition), 2003

Galactic Structure and Evolution

John P. Huchra, in Encyclopedia of Physical Science and Technology (Third Edition), 2003

Star Clusters

Steven N. Shore, in Encyclopedia of Physical Science and Technology (Third Edition), 2003

The Hans Bethe Centennial Volume 1906-2006

It is thus a major occurrence in nucleosynthesis theory when the solar abundances, traditionally taken as representative of Population I stars in our Galaxy, are modified. Recent revisions to the solar abundance set have been discussed by Lodders (2003) and Asplund et al. (2005), Asplund (2005).

Primordial nucleosynthesis

Spite & Spite (1982) found ( 7 Li / H) II ∼10 −10 in old low metallicity Population II stars. The abundance inferred for younger Population I stars is ( 7 Li / H) I ∼10 −9. Therefore the Spite's Population II stars seem ideal for estimating the primordial 7 Li abundance: ( 7 Li / H) p ∼10 −10 since it agrees with the SBBN model prediction.

Helioseismology and solar abundances

The revision in solar metallicity also affects models for other stars. This is because the abundances of stars are often expressed relative to solar abundances. Very often stellar metallicity is expressed as [ Fe/H], and translating this to Z assumes that solar metallicity is known.

Frontiers in nuclear astrophysics

C.A. Bertulani, T. Kajino, in Progress in Particle and Nuclear Physics, 2016

When were stars first divided into populations?

Stars observed in galaxies were originally divided into two populations by Walter Baade in the 1940s. Although a more refined means of classifying stellar populations has since been established (according to whether they are found in the thin disk, thick disk, halo or bulge of the galaxy ), astronomers have continued to coarsely classify stars as ...

What type of explosions are the Pop I stars in?

These elements are produced primarily in Type II supernova explosions (the explosions of massive stars), and indicate that the Pop I stars in the bulge formed early in the star formation history of the Milky Way.

Which star has the most metals?

Pop I stars are the most metal-rich, with metallicities ranging from approximately 1/10th to three times that of the Sun (i.e. from [Z/H]=-1.0 up to [Z/H]=+0.5).

Is the Sun a Pop I star?

The Sun ( [Z/H]~1.6) is a fairly typical Pop I star, as are most of the stars in the immediate solar neighbourhood. In fact, the majority of the stars contained within the thin disks of galaxies are Pop I stars, but Pop I stars can also found in the bulge.

Which star is considered a population I?

The Sun is considered Population I, a recent star with a relatively high 1.4 percent metallicity.

Where are the population 2 stars?

These objects were formed during an earlier time of the universe. Intermediate Population II stars are common in the bulge near the centre of the Milky Way, whereas Population II stars found in the galactic halo are older and thus more metal-d Globular clusters also contain high numbers of Population II stars.

How many solar masses does a population II star have?

Analysis of data of extremely low- metallicity Population II stars such as HE0107-5240, which are thought to contain the metals produced by Population III stars, suggest that these metal-free stars had masses of 20 to 130 solar masses.

How many ultra metal poor stars are there?

Thus far, they have uncovered and studied in detail about ten ultra metal poor (UMP) stars (such as Sneden's Star, Cayrel's Star, BD +17° 3248) and three of the oldest stars known to date: HE0107-5240, HE1327-2326 and HE 1523-0901.

What is the difference between the blue and yellow stars in the Milky Way?

The blue regions in the spiral arms comprise the younger Population I stars, while the yellow stars in the central bulge are the older Population II stars . In reality, many Population I stars are also found mixed in with the older Population II stars.

What are the characteristics of a population II star?

A characteristic of Population II stars is that despite their lower overall metallicity, they often have a higher ratio of " alpha elements " (elements produced by the alpha process, namely O, Ne, etc.) relative to Fe as compared to Population I stars; current theory suggests this is the result of Type II supernovas being more important contributors to the interstellar medium at the time of their formation, whereas Type Ia supernova metal-enrichment came at a later stage in the universe's development.

Which star has the highest metallicity?

Population I, or metal-rich, stars are young stars with the highest metallicity out of all three populations, and are more commonly found in the spiral arms of the Milky Way galaxy. The Earth 's Sun is an example of a metal-rich star and is considered as an intermediate Population I star, while the solar-like Mu Arae is much richer in metals.

What is a population I star?

Population I stars or metal-rich stars are those young stars whose metallicity is highest. The Earth's Sun is an example of a Population I star. Population I stars are common in the Spiral arms of the Milky Way galaxy.

How many solar masses does a star have?

The highest-mass star which may form today is about 110 solar masses. Any attempt to form a star greater than this results in the protostar blowing itself apart during the initial ignition of nuclear reactions. Without enough carbon, oxygen and nitrogen in the core, however, the CNO cycle could not begin and the star would not go nuclear with such enthusiasm. Direct fusion through the Proton-proton chain does not proceed quickly enough to produce the copious amounts of energy such a star would need to support its immense bulk. The end result would be the star collapsing into a black hole without ever actually shining properly. This is why astronomers consider population III to be somewhat of a mystery--by all rights they should not exist, yet they're needed to explain the quasar observations.

Why is the metallicity of the Milky Way higher than the density of the stars?

The gradient in metallicity is attributed to the density of stars in the galactic centre: there are more stars in the centre of the galaxy and, so, over time, more metals have been returned to the ISM and incorporated into new stars. By a similar mechanism, larger galaxies tend to have higher metallicities than smaller ones. In the case of the Magellanic Clouds, two small Irregular galaxies orbiting the Milky Way, the Large Magellanic Cloud has a metallicity about 40 per cent of the Milky Way, while the Small Magellanic Cloud has a metallicity about 10 per cent of the Milky Way.

Is the Sun an intermediate population I star?

Generally, the youngest stars are found further in, and intermediate population I stars are further out, etc. The Sun is considered an intermediate population I star. Population I stars have regular elliptical orbits of the galactic centre, with a low relative velocity. The high metallicity of Population I stars makes them more likely to possess planetary systems than the other two populations, since planets, particulalry terrestrial planets, formed by accretion of metals.

Where are population 2 stars found?

Population II stars tend to be found in globular clustersand the nucleus of a galaxy. They tend to be 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.

How are stars classified?

Stars may be classified by their heavy element abundance, which correlates with their age and the type of galaxy in which they are found. Population I stars include the sun and tend to be luminous, hot and young, concentrated in the disks of spiral galaxies. They are particularly found in the spiral arms.

Answer

Population I stars include the sun and tend to be luminous, hot and young, concentrated in the disks of spiral galaxies. ... Population II stars tend to be found in globular clusters and the nucleus of a galaxy. They tend to be older, less luminous and cooler than Population I stars.

New questions in Biology

Need Help!What conclusion can be drawn about the number of elements the make up the majority of the world in which we live and the total number of ele …

Overview

Chemical classification by Baade

Stellar development

See also

Further reading