T = 5800 K
... wavelength of 386 nm (violet). In the visible light from this star, there would be a bit more blue and violet than the other colors. The star would have a faint blue color. Our sun has a surface temperature of 5800 K. The wavelength at which it is brightest is 500 nm (green). It has a faint yellow c ...
... wavelength of 386 nm (violet). In the visible light from this star, there would be a bit more blue and violet than the other colors. The star would have a faint blue color. Our sun has a surface temperature of 5800 K. The wavelength at which it is brightest is 500 nm (green). It has a faint yellow c ...
Astronomy
... stars. During the late stages of stellar evolution, massive stars can burn helium into carbon, oxygen, silicon, sulfur, and iron. • Elements heavier than iron are produced in two ways: in the outer envelopes of supergiant stars and in the explosion of a supernova. • All carbon-based life on Earth is ...
... stars. During the late stages of stellar evolution, massive stars can burn helium into carbon, oxygen, silicon, sulfur, and iron. • Elements heavier than iron are produced in two ways: in the outer envelopes of supergiant stars and in the explosion of a supernova. • All carbon-based life on Earth is ...
STELLAR FORMATION AND EVOLUTION
... the star's luminosity suddenly increases a billion-fold. For a few days, this single star can be as bright as the entire galaxy. The star has become a supernova. The ejected material is extremely rich in the elements beyond hydrogen and helium; not only is the original light element shell ejected, b ...
... the star's luminosity suddenly increases a billion-fold. For a few days, this single star can be as bright as the entire galaxy. The star has become a supernova. The ejected material is extremely rich in the elements beyond hydrogen and helium; not only is the original light element shell ejected, b ...
Power-point slides for Lecture 5
... the core called the “homologous core” that collapses subsonically (e.g., Goldreich & Weber, ApJ, 238, 991 (1980); Yahil ApJ, 265, 1047 (1983)). This is also approximately equivalent to the “sonic core”. This part of the core is called homologous because it can be shown that within it, vcollapse is p ...
... the core called the “homologous core” that collapses subsonically (e.g., Goldreich & Weber, ApJ, 238, 991 (1980); Yahil ApJ, 265, 1047 (1983)). This is also approximately equivalent to the “sonic core”. This part of the core is called homologous because it can be shown that within it, vcollapse is p ...
WINNING STORY - Atlantis Short Story Contest
... That is a poetic way to come into being, if you ask me. I guess I am a poetic particle. But what is even more artistic is the phenomenon that created me, and hundreds of thousands of other atoms like me: the death of a star. What I can say is this: a star surely knows how to make a powerful, dramati ...
... That is a poetic way to come into being, if you ask me. I guess I am a poetic particle. But what is even more artistic is the phenomenon that created me, and hundreds of thousands of other atoms like me: the death of a star. What I can say is this: a star surely knows how to make a powerful, dramati ...
charts_set_7
... forms many stars, mainly in clusters, in different parts at different times. Massive stars (50-100 MSun) take about 106 years to form, least massive (0.1 MSun) about 109 years. Lower mass stars more likely to form. In Milky Way, a few stars form every year. ...
... forms many stars, mainly in clusters, in different parts at different times. Massive stars (50-100 MSun) take about 106 years to form, least massive (0.1 MSun) about 109 years. Lower mass stars more likely to form. In Milky Way, a few stars form every year. ...
Chapter 14 Origins
... Immediately after the big bang there was only energy present, but the stars are formed of matter. (a) ...
... Immediately after the big bang there was only energy present, but the stars are formed of matter. (a) ...
AST1100 Lecture Notes
... makes the pressure and thereby the temperature in the core higher than in the case of a low mass star. The forces of gravity are larger and therefore the pressure needs to by higher in order to maintain hydrostatic equilibrium. The carbon-oxygen core contracts, but before it gets degenerate the temp ...
... makes the pressure and thereby the temperature in the core higher than in the case of a low mass star. The forces of gravity are larger and therefore the pressure needs to by higher in order to maintain hydrostatic equilibrium. The carbon-oxygen core contracts, but before it gets degenerate the temp ...
Powerpoint
... Pattern of absorption lines depends on temperature (mainly) and chemical composition. Spectra give most accurate info on these as well as: density in atmosphere gravity at surface velocity of star towards or from us ...
... Pattern of absorption lines depends on temperature (mainly) and chemical composition. Spectra give most accurate info on these as well as: density in atmosphere gravity at surface velocity of star towards or from us ...
The ISM and Stellar Birth
... 1000pc from Earth will look about 2 magnitudes fainter than if space were empty completely • Dust thought to come from stellar ‘winds’, blowing out molecules of hydrogen, carbon, oxygen and other elements which cool and coalesce into dust grains ...
... 1000pc from Earth will look about 2 magnitudes fainter than if space were empty completely • Dust thought to come from stellar ‘winds’, blowing out molecules of hydrogen, carbon, oxygen and other elements which cool and coalesce into dust grains ...
Lecture20
... Newer stars have 1% - 4% heavier elements Old stars have 1/10 to 1/100 as many heavier elements as the Sun ...
... Newer stars have 1% - 4% heavier elements Old stars have 1/10 to 1/100 as many heavier elements as the Sun ...
Measuring Stellar Distances
... Even the closest star to the Earth (Proxima Centauri) has a parallax less than 1 arcsecond. A star at a distance of 20 parsecs from the sun would exhibit a parallactic angle of only 0.05 seconds or arc, approximately a factor of 10 below the best angular resolution that can be achieved in a single i ...
... Even the closest star to the Earth (Proxima Centauri) has a parallax less than 1 arcsecond. A star at a distance of 20 parsecs from the sun would exhibit a parallactic angle of only 0.05 seconds or arc, approximately a factor of 10 below the best angular resolution that can be achieved in a single i ...
PoA Examples Sheet 3
... Provide a physical explanation for this scaling. Derive furthermore how the frequency integrated power per unit volume depends on temperature. 5. The photospheric temperature of an optically thick accretion disc varies with radius as T ∝ R−3/4 . Explain why you expect the spectrum of the radiation p ...
... Provide a physical explanation for this scaling. Derive furthermore how the frequency integrated power per unit volume depends on temperature. 5. The photospheric temperature of an optically thick accretion disc varies with radius as T ∝ R−3/4 . Explain why you expect the spectrum of the radiation p ...
![Global Warming_Notes_for_Test_Review[1]](http://s1.studyres.com/store/data/009490554_1-1d4a9735243ab8423aa4808909f160ae-300x300.png)
Global Warming_Notes_for_Test_Review[1]
... 3. A planet’s gravity is caused by its spin. False A planets gravity is caused by its mass. 4. Fusion is the process that powers the Sun and other Stars. True 5. A black hole is the beginning stage of every massive star. False. A black hole is the ending stage of a massive star. 6. A nebula is a vas ...
... 3. A planet’s gravity is caused by its spin. False A planets gravity is caused by its mass. 4. Fusion is the process that powers the Sun and other Stars. True 5. A black hole is the beginning stage of every massive star. False. A black hole is the ending stage of a massive star. 6. A nebula is a vas ...
Surveying the Stars
... • 19th century astronomer N.R. Pogson proposed a formula which captures the essence of the Greek idea. • A mag=2 star is 2.5 times brighter than a mag=3 star, and a mag 3 star is 2.5 times brighter than a mag=4 star, etc. • If you imagine moving a star to a standard distance of 10 parsecs, the appar ...
... • 19th century astronomer N.R. Pogson proposed a formula which captures the essence of the Greek idea. • A mag=2 star is 2.5 times brighter than a mag=3 star, and a mag 3 star is 2.5 times brighter than a mag=4 star, etc. • If you imagine moving a star to a standard distance of 10 parsecs, the appar ...
the universe
... has enough hydrogen fuel to last another five billion years. The sun and other stars eventually begin to run out of hydrogen. Gravity makes the core of the star smaller and hotter, which results in the outer layers expanding. They eventually expand so much that the star becomes a red giant star. Aft ...
... has enough hydrogen fuel to last another five billion years. The sun and other stars eventually begin to run out of hydrogen. Gravity makes the core of the star smaller and hotter, which results in the outer layers expanding. They eventually expand so much that the star becomes a red giant star. Aft ...
Read
... compare various stars with each other. Notice that you’ll need to solve the above equation ...
... compare various stars with each other. Notice that you’ll need to solve the above equation ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.