Types of Stars
... • Astronomers classify stars by their color, size, and brightness. Other properties of stars are chemical composition and mass. • Color and Temperature – a stars color indicates the temperature of its’ surface. • The hottest stars appear blue • The cooler stars appear red • The spectrum of color in ...
... • Astronomers classify stars by their color, size, and brightness. Other properties of stars are chemical composition and mass. • Color and Temperature – a stars color indicates the temperature of its’ surface. • The hottest stars appear blue • The cooler stars appear red • The spectrum of color in ...
summary of key concepts: week #1
... about 10 billion years, is very long), and when they die they normally eject gas back into space and leave behind a stellar remnant. If the star is massive enough, this can be a black hole. 2. A galaxy is an `island of stars’ held together by gravity. Our own galaxy, called the Milky Way, has about ...
... about 10 billion years, is very long), and when they die they normally eject gas back into space and leave behind a stellar remnant. If the star is massive enough, this can be a black hole. 2. A galaxy is an `island of stars’ held together by gravity. Our own galaxy, called the Milky Way, has about ...
HR Diagram - Geneva 304
... 53. Why does nuclear fusion produce so much energy? 54. Explain why stars favor fusion reactions over fission reactions. 55. Describe what conditions are necessary for two nuclei to fuse. ...
... 53. Why does nuclear fusion produce so much energy? 54. Explain why stars favor fusion reactions over fission reactions. 55. Describe what conditions are necessary for two nuclei to fuse. ...
Ia 超新星的
... An isolated WD is stable and almost inert, because its temperature is not high enough to induce any substantial nuclear reactions. This isolated dead star can exist almost indefinitely, slowly cooling down to black dwarf as it radiates its energy into space. No supernova explosion will ensue. A very ...
... An isolated WD is stable and almost inert, because its temperature is not high enough to induce any substantial nuclear reactions. This isolated dead star can exist almost indefinitely, slowly cooling down to black dwarf as it radiates its energy into space. No supernova explosion will ensue. A very ...
The Hertzsprung-Russell Diagram
... their life cycles. The Main Sequence is set by hydrogen fusion. ...
... their life cycles. The Main Sequence is set by hydrogen fusion. ...
Universe Now - Course Pages of Physics Department
... • The structure of a black hole: – Singularity: the location of the entire mass – infinite density. – Event horizon: an undetectable surface which marks the point of inevitable falling into singularity. The radius can be calculated if the mass is known (for 1 M, 3 km). ...
... • The structure of a black hole: – Singularity: the location of the entire mass – infinite density. – Event horizon: an undetectable surface which marks the point of inevitable falling into singularity. The radius can be calculated if the mass is known (for 1 M, 3 km). ...
Sakurai`s Object - Department of Physics, HKU
... • It consists of a non-burning carbon-oxygen core, a helium burning shell and a hydrogen burning shell. • Shortly before the formation of an AGB, convective instability in some higher mass pre-AGBs may lead to the “second dredgeup”, resulting in an increase of He, C and N on the stellar surface. ...
... • It consists of a non-burning carbon-oxygen core, a helium burning shell and a hydrogen burning shell. • Shortly before the formation of an AGB, convective instability in some higher mass pre-AGBs may lead to the “second dredgeup”, resulting in an increase of He, C and N on the stellar surface. ...
regan-gas-10jul2010
... Medieval alchemist…trying to turn base metals into gold… Mistake…to try and use ‘chemistry’…needed nuclear physics ...
... Medieval alchemist…trying to turn base metals into gold… Mistake…to try and use ‘chemistry’…needed nuclear physics ...
Chapter 3: the Sun - University of Waterloo
... collapsing material forms a disk. Eventually T becomes high enough that molecular hydrogen dissociates; this absorbs some of the energy supporting the protostar, so the core begins to collapse further, until it becomes ~30% larger than the present Solar radius (but still much less massive). The prot ...
... collapsing material forms a disk. Eventually T becomes high enough that molecular hydrogen dissociates; this absorbs some of the energy supporting the protostar, so the core begins to collapse further, until it becomes ~30% larger than the present Solar radius (but still much less massive). The prot ...
Death of Massive Stars
... 1. Speed of light is a constant and nothing can travel faster Speed of light = 300,000 km/s (180,000 miles/s) 2. The faster something moves, the slower time appears to move for it -For every second that passes on Earth, 0.99999999967 seconds pass on the international space station (orbiting at about ...
... 1. Speed of light is a constant and nothing can travel faster Speed of light = 300,000 km/s (180,000 miles/s) 2. The faster something moves, the slower time appears to move for it -For every second that passes on Earth, 0.99999999967 seconds pass on the international space station (orbiting at about ...
s%nffi - mrtavares
... Early in the twentieth century, Einar Hertzsprung and Henry Russell independently developed a graph used to study stars. It is now called a Hertzsprr.urg-Russell diagran-r (H-R ciiagram). ffiA HertzsprungRussell diagram shgws the relationship between the absolute magnitude and temperature of stars. ...
... Early in the twentieth century, Einar Hertzsprung and Henry Russell independently developed a graph used to study stars. It is now called a Hertzsprr.urg-Russell diagran-r (H-R ciiagram). ffiA HertzsprungRussell diagram shgws the relationship between the absolute magnitude and temperature of stars. ...
Physics Observing The Universe
... Life of a large star – Stage 6: Pulsars Pulsars are highly magnetized neutron stars that emit a beam of e/m radiation. They rotate very rapidly. e,.g once every 1.4 milliseconds to 8.5 seconds. The radiation can only be observed when the beam of emission is pointing towards Earth. This is called th ...
... Life of a large star – Stage 6: Pulsars Pulsars are highly magnetized neutron stars that emit a beam of e/m radiation. They rotate very rapidly. e,.g once every 1.4 milliseconds to 8.5 seconds. The radiation can only be observed when the beam of emission is pointing towards Earth. This is called th ...
We Are Stardust: Synthesis of the Elements Essential for Life Aparna
... 3 4He → 12C at temp. = 100 million degrees; carbon → nitrogen and oxygen at temp. = several hundred million degrees. • Thus, a general pattern emerges: when the star exhausts one fuel, it can no longer support itself against gravity, so it contracts until it reaches a core temperature that can ignit ...
... 3 4He → 12C at temp. = 100 million degrees; carbon → nitrogen and oxygen at temp. = several hundred million degrees. • Thus, a general pattern emerges: when the star exhausts one fuel, it can no longer support itself against gravity, so it contracts until it reaches a core temperature that can ignit ...
PHYS-633: Problem set #2
... Helium, with a mass fraction Y ≈ 0.26. Use the above to compute the average mass fractions Xtams and Ytams at the end of the sun’s main sequence life (known as “TAMS”, for “terminal age main sequence”). e. After the main sequence, the sun will evolve into a Red Giant with L ≈ 5000L , by burning H i ...
... Helium, with a mass fraction Y ≈ 0.26. Use the above to compute the average mass fractions Xtams and Ytams at the end of the sun’s main sequence life (known as “TAMS”, for “terminal age main sequence”). e. After the main sequence, the sun will evolve into a Red Giant with L ≈ 5000L , by burning H i ...
What is a Scientist? - Cockeysville Middle School
... Identify the temperature associated with each color, and include an example of a star that would appear each color. ...
... Identify the temperature associated with each color, and include an example of a star that would appear each color. ...
main sequence
... A main sequence star will experience only small fluctuations in luminosity and temperature. The amount of time a star spends in this phase depends on its mass. Large, massive stars will have a short main sequence stage while less massive stars will remain in main sequence much longer. Very massive s ...
... A main sequence star will experience only small fluctuations in luminosity and temperature. The amount of time a star spends in this phase depends on its mass. Large, massive stars will have a short main sequence stage while less massive stars will remain in main sequence much longer. Very massive s ...
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.