Lecture 10
... *All stars above 6,000 K look more or less white to the human eye because they emit plenty of radiation at all visible wavelengths. ...
... *All stars above 6,000 K look more or less white to the human eye because they emit plenty of radiation at all visible wavelengths. ...
SR Stellar Properties
... Name: ________________________________ Date: ___________________ Period: _________ H-R Diagram Scientists began to learn about stars by observing properties of stars, including brightness and color. Astronomers tried to make sense of the star data by grouping together stars with similar properties. ...
... Name: ________________________________ Date: ___________________ Period: _________ H-R Diagram Scientists began to learn about stars by observing properties of stars, including brightness and color. Astronomers tried to make sense of the star data by grouping together stars with similar properties. ...
How Stars Evolve
... What would happen to a contracting cloud fragment if it were not able to radiate away its thermal energy? A. It would continue contracting, but its temperature would not change B. Its mass would increase ...
... What would happen to a contracting cloud fragment if it were not able to radiate away its thermal energy? A. It would continue contracting, but its temperature would not change B. Its mass would increase ...
10.1 The Solar Neighborhood Barnard`s Star
... looks quite different: These stars are all more luminous than the Sun. Two new categories appear here – the red giants and the blue giants. Clearly, the brightest stars in the sky appear bright because of their enormous luminosities, not their proximity. ...
... looks quite different: These stars are all more luminous than the Sun. Two new categories appear here – the red giants and the blue giants. Clearly, the brightest stars in the sky appear bright because of their enormous luminosities, not their proximity. ...
Nuclear fusion in stars
... • If R increases by a factor of 4, r does the same by factor of 8. This means that a collapsing cloud can fragment ! into smaller collapsing clouds. • This process ends with star formation or when rotational speed becomes too high (conservation of angular momentum) • Hierarchical collapse can produc ...
... • If R increases by a factor of 4, r does the same by factor of 8. This means that a collapsing cloud can fragment ! into smaller collapsing clouds. • This process ends with star formation or when rotational speed becomes too high (conservation of angular momentum) • Hierarchical collapse can produc ...
HR Diagram
... H-R Diagram Scientists began to learn about stars by observing properties of stars, including brightness and color. Astronomers tried to make sense of the star data by grouping together stars with similar properties. The Hertzsprung-Russell diagram provides a way to group similar stars. The H-R dia ...
... H-R Diagram Scientists began to learn about stars by observing properties of stars, including brightness and color. Astronomers tried to make sense of the star data by grouping together stars with similar properties. The Hertzsprung-Russell diagram provides a way to group similar stars. The H-R dia ...
The Later Evolution of Low Mass Stars (< 8 solar masses)
... http://en.wikipedia.org/wiki/Ring_Nebula AGB stars are known to lose mass at a prodigious rate during their final stages, around 10-5 - 10-4 solar masses per year. This obviously cannot persist for much over 100,000 years. The mass loss is driven in part by the pulsational instability of the thin he ...
... http://en.wikipedia.org/wiki/Ring_Nebula AGB stars are known to lose mass at a prodigious rate during their final stages, around 10-5 - 10-4 solar masses per year. This obviously cannot persist for much over 100,000 years. The mass loss is driven in part by the pulsational instability of the thin he ...
Properties of Stars - Mr. Carter`s Earth
... The Hertzsprung-Russell diagram is actually a graph that illustrates the relationship that exists between the average surface temperature of stars and their absolute magnitude, which is how bright they would appear to be if they were all the same distance away. Rather than speak of the brightness of ...
... The Hertzsprung-Russell diagram is actually a graph that illustrates the relationship that exists between the average surface temperature of stars and their absolute magnitude, which is how bright they would appear to be if they were all the same distance away. Rather than speak of the brightness of ...
ppt - Astronomy & Physics
... To get the total luminosity of the star, L, we need to multiply E by the surface area (4pR2) of a star of radius R: L=4pR2sT4 What happens if we plot temperature vs luminosity for many different types of stars? ...
... To get the total luminosity of the star, L, we need to multiply E by the surface area (4pR2) of a star of radius R: L=4pR2sT4 What happens if we plot temperature vs luminosity for many different types of stars? ...
Stellar Evolution
... A star with 3x the sun’s mass or more has enough mass so that when it collapses the gravitational field becomes so strong that the escape velocity near it becomes faster than light. Light itself cannot escape…. A Black Hole. The distance from the star called the Event Horizon is where escape velocit ...
... A star with 3x the sun’s mass or more has enough mass so that when it collapses the gravitational field becomes so strong that the escape velocity near it becomes faster than light. Light itself cannot escape…. A Black Hole. The distance from the star called the Event Horizon is where escape velocit ...
Monday, April 15
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
Galaxies - C. Levesque
... this creates a black hole • A black hole is an object so dense that not even light can escape it. • We can find black holes by looking for objects in space ...
... this creates a black hole • A black hole is an object so dense that not even light can escape it. • We can find black holes by looking for objects in space ...
Star
A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.