Population II
Stars observed in galaxies were originally divided into two populations by Walter Baade in the 1940s.
Population I And Ii
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in astronomy: see stellar populations.
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Population II stars are metal poor stars, containing about 0.1% metals. These stars can be found in the spherical portion of the galaxy (the halo and the bulge). Often these stars have tipped and elliptical orbits.
Population projections from the 1900s to 2050
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Stellar population
Stars observed in our galaxy appear to group into two general types called Population I and Population II.
stellar populations
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Stellar Populations
type I: metal-rich (2-3%) disk stars which formed from material enriched with metals from a previous star-forming generation. type II: metal-poor (0.001-0.1%) halo stars.
"For the first time, we have a direct handle on the population of comets in this outer region. We now know, conclusively, that our solar system doesn't end at Neptune.
POPULATION II
When we come to study the older populations of the Magellanic Clouds, we look past the brilliant associations with their blue supergiants and HII regions, past the Cepheid variables, ...
Population evolution combines the history of star formation in a galaxy and stellar evolution of its constituents, giving changes in the HR diagram of a galaxy (generally changing from place to place in the galaxy) with time.
Populations of Stars
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Population I: Stars rich in atoms heavier than helium; usually relatively young stars found in the disk of a galaxy.
POPULATION I STARS - Relatively young stars found mainly in the disk of the Galaxy. Population I stars are the most metal-rich, with metallicities ranging from ~0.1 to 3 times that of the Sun (i.e., [Z/H] from -1.0 to +0.5).
Population I
Stars rich in atoms heavier than helium; nearly always relatively young stars found in the disk of the galaxy.
Population II ...
Populations, stellar. There are essentially two types of star regions. I - in which the brightest stars are hot and white; and II - in which the brightest stars are old Red Giants.
Populations I and II
Two classes of stars introduced by Baade in 1944.
POPULATION 2 STARS
Population 2 stars are relatively old stars. They are found mainly in the halo of galaxies.
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[edit] Population II stars
Population II or metal-poor stars are those with relatively little metal.
Human population
Earth at night, showing population centres.
Composite of pictures taken between
October 1994 and March 1995.
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STELLAR POPULATIONS
Aside from their shapes, the three components of the Galaxy"disk, bulge, and halo"have several other properties that distinguish them from one another.
Stellar Population - A group of stars that are similar in spatial distribution, chemical composition, and age
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Population Growth. A simple (though approximate) model of population growth is the Malthusian growth model. The preferred population growth model is the logistic function.
Model of a particle in a potential-field.
Populations of organisms change over time
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Population I - hot, young stars present, which are chemically like the Sun; their presence indicates that current star formation is going on ...
Population I and II stars are known to exist.In the early 1990s, another satellite, the Cosmic Background Explorer (Cobe), found all-pervasive microwave radiation in space thought to be the "echo" of the Big Bang.
population I - (n.)
The class of stars with relatively high abundances of heavy elements. These stars are generally found in the disk and spiral arms of spiral galaxies, and are relatively young.
Population II Stars: Relatively old stars, containing a smaller fraction of metals, found mainly in the halo of the Galaxy and in Globular Clusters.
The population of so-called Trojan asteroids share an orbit with a planet but remain fixed in the stable L4 and L5 positions 60 degrees ahead and behind the planet on its orbit.
When a population of "particles" (molecules, atoms or ions - but mostly ions when talking about a star's surface) are heated, they move around very quickly - especially if they are a gas, as they are on the surface of a star.
any of a population of small bodies, similar to asteroids in size but to comets in composition, that revolve around the Sun in the outer solar system, mainly between the orbits of Jupiter and Neptune.
These old population II giant stars are mostly found in globular clusters. They are characterised by their short periods, usually about 1.5 hours to a day and have a brightness range of 0.3 to 2 magnitudes. Spectral classes range from A7 to F5.
population (NASA SP-7, 1965) In statistical usage, any definite class of individuals or objects. Also called universe. Compare sample.
Atens:
NEO sub-population with semi major axis smaller than 1 AU and aphelion distance larger than 0.983 AU.
Astronomical Unit (AU):
Average distance of the Earth from the Sun. Approximately equal to 150 million kilometres.
The tendency of a population of stars to have a mean rotation velocity around the galactic center that lags behind that of the local standard of rest.
In statistical terminology, any numerical constant derived from a population or a probability distribution. Specifically, it is an arbitrary constant in the mathematical expression of a probability distribution.
Among the most famed stars of the entire sky, surely rival in renown to Sirius and Polaris even though not visible to much of the world's population, is the "foot of the Centaur," Rigil Kentaurus, "Rigil Kent," the first star of Centaurus, ...
Population of the Earth
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We call those stars with very little heavy elements "population II stars" and those with Sun-like heavy element abundances "population I stars".
He recognized that within a local population the individual with, for example, the sharper beak, the longer horn, or the brighter feather might have a better chance to survive and reproduce than other individuals.
with a strong concentration of stars (and gas and dust) within 3,000 light-years (ly) of the galactic plane, which includes the so-called "thin disk" that has more relatively younger stars within 1,500 ly of the plane (more on stellar population ...
It should be emphasized again that natural selection works on populations; "a fish" doesn't mean a single fish, it means a population of interbreeding fish.
Furthermore, they noted that the S class dominated the population at the inner edge of the asteroid belt, whereas the C class was dominant in the middle and outer regions of the belt. In 1982 other American astronomers, Jonathan C.
Young metal rich stars are called Population I and old metal poor stars are called Population II. (A possibly helpful mnemonic: II stars are older than I stars because II is bigger than I.) Globular clusters are old clusters of population II stars.
The Hubble images, taken with the Advanced Camera for Surveys, identify three stellar populations in the SMC and in the region of the NGC 346 nebula -- a total of 70,000 stars. The oldest population is 4.5 billion years, roughly the age of our Sun.
Launches from the east coast of the United States (the Kennedy Space Center at Cape Canaveral, Florida) are suitable only for low inclination orbits because major population centers underlie the trajectory required for high-inclination launches.
It contains several million Population II stars, oldest stars to be observed. The stars in the center of the cluster appear so close to each other than the distance between them is believed to be only 0.1 light-years.
Cepheid variables subdivide into two classes: the classical Cepheid variables, which are population I stars-stars with a high metallicity, and, therefore, of the current generation of stars-and the W Virginis variables, ...
In contrast, spiral galaxies are flattened disk systems containing not only some old stars but also large populations of young stars, much gas and dust, and molecular clouds that are the birthplace of stars.
There were songs spread among the slave population which included references to the "Drinking Gourd." The songs said to follow it to get to a better life.
It is indeed rare at most centers of population, but in Alaska, for instance, or in much of Canada, the aurora is quite common.
So why is Saturn the most sought after astronomical object among much of the general population? The answer is simple: Saturn's magnificent set of rings.
It is estimated that Finland has the largest number of amateur astronomers in the world per head of population. According to URSA (URSA Astronomical Association) there are between 12,000 and 13,000 astronomy club members.
population is growing again, and rain forest is being cut to make farmland," Sever said. The shrinking number of trees can be seen in satellite images. This decrease in trees may be causing clouds to form higher and later in the day.
If we know the total population (200,000) and the lifetime (20,000,000 years), we can deduce that a new pulsar must be born in our galaxy roughly every 100 years (assuming that the population remains steady).
The most common comets belong to a population called the short-period comets that have only mildly elliptical orbits that carry them out to a region lying from Jupiter to beyond the orbit of Neptune.
The solar system boasts a population of eight planets, three dwarf planets, dozens of satellites and countless small solar-system bodies. The charts below list a few properties of the planets and their satellites.
Polaris pulsates with 3.97 day period. The luminosity varies by 0.15 magnitude. Polaris is classified as a Population II Cepheid. Stars of this type are about 1.5 magnitudes smaller than Population I Cepheids.
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large galaxy clusters with unusually high population densities
rich-field telescope
a telescope designed to show a large field of view at low magnification ...
This process of being a Helium burning star lasts around 700 000 years and is the Population II stage. The star is now on what it known as the Main Sequence - an escalator that will climb, relatively quickly, to supernova-hood.
Definition: evolution: A change in the gene pool of a population over time.
Space Tragedies9 Planets in Nine DaysAstronomy 101
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