PPT
... stars So what? It shows stars of different ages and in different stages, all at the same time. It is a great tool to check your understanding of the star life cycle. ...
... stars So what? It shows stars of different ages and in different stages, all at the same time. It is a great tool to check your understanding of the star life cycle. ...
protostars low mass stars intermediatemass stars red giant planetary
... converts hydrogen into helium. Not many changes occur during the main sequence, as stars are very stable at this point. Changes only begin when the star begins to run out of hydrogen in its core and the rate of fusion decreases. ...
... converts hydrogen into helium. Not many changes occur during the main sequence, as stars are very stable at this point. Changes only begin when the star begins to run out of hydrogen in its core and the rate of fusion decreases. ...
Stellar Evolution: After the Main Sequence
... As a cluster ages, the main sequence is “eaten away” from the upper left as stars of progressively smaller mass evolve into red giants ...
... As a cluster ages, the main sequence is “eaten away” from the upper left as stars of progressively smaller mass evolve into red giants ...
File
... Main sequence stars are stars that are fusing hydrogen atoms to form helium atoms in their cores. Most of the stars in the universe are main sequence stars Red Giants are very large stars of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when ...
... Main sequence stars are stars that are fusing hydrogen atoms to form helium atoms in their cores. Most of the stars in the universe are main sequence stars Red Giants are very large stars of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when ...
Facts - GreenSpirit
... The gases hydrogen and helium are attracted and condense through gravity ...
... The gases hydrogen and helium are attracted and condense through gravity ...
Life cycle of the Stars - Christos N. Hadjichristidis
... Throughout its life, these two forces determine the stages of a star’s life. ...
... Throughout its life, these two forces determine the stages of a star’s life. ...
Yes, we are all star dust. Even Gary!
... naturally occurring elements heavier than Iron (ie the metals and rare earths) ...
... naturally occurring elements heavier than Iron (ie the metals and rare earths) ...
Slide 1
... Depending on the mass of the star, its lifetime may be a few million years to trillions of years. Lower massed stars can generate energy for billions of years. ...
... Depending on the mass of the star, its lifetime may be a few million years to trillions of years. Lower massed stars can generate energy for billions of years. ...
Discussion Activity #11a
... 2. Why can the fusion of carbon occur in intermediate- and high-mass stars but not in low-mass stars? A. It is because the cores of low-mass stars never get hot enough for carbon fusion. B. It is because carbon fusion can occur only in the stars known as carbon stars. C. It is because the cores of l ...
... 2. Why can the fusion of carbon occur in intermediate- and high-mass stars but not in low-mass stars? A. It is because the cores of low-mass stars never get hot enough for carbon fusion. B. It is because carbon fusion can occur only in the stars known as carbon stars. C. It is because the cores of l ...
The Evolution of Massive Stars
... Neutron Stars: a brief history • Basic physics understood in the 1930s • At that time, no known counterparts • In the 1950s and 1960s, more and more strange objects found, but where were the neutrons stars, or did they even exist? • The case of the Crab Nebula (supernova of 1054 AD) ...
... Neutron Stars: a brief history • Basic physics understood in the 1930s • At that time, no known counterparts • In the 1950s and 1960s, more and more strange objects found, but where were the neutrons stars, or did they even exist? • The case of the Crab Nebula (supernova of 1054 AD) ...
Supernova
... • The photons are energetic enough to break up iron nuclei. • The particles from the broken nuclei fuse with iron to create heavy elements. • This matter goes to form new stars and planets. ...
... • The photons are energetic enough to break up iron nuclei. • The particles from the broken nuclei fuse with iron to create heavy elements. • This matter goes to form new stars and planets. ...
molecular clouds
... Molecular Clouds In these nebulae much of the hydrogen is in the molecular (H2) form, so these nebulae are called molecular clouds. The largest such formations are called giant molecular clouds (GMC). ...
... Molecular Clouds In these nebulae much of the hydrogen is in the molecular (H2) form, so these nebulae are called molecular clouds. The largest such formations are called giant molecular clouds (GMC). ...
ASTR2050 Spring 2005 • In this class we will cover: Brief review
... Hydrogen in core is used up. Temperature in core is not high enough to burn helium. Hydrogen burns in “shell”. Helium core is “degenerate”. H burning He core is very dense ...
... Hydrogen in core is used up. Temperature in core is not high enough to burn helium. Hydrogen burns in “shell”. Helium core is “degenerate”. H burning He core is very dense ...
Study Notes for Chapter 30: Stars, Galaxies, and the Universe
... 2. A large, bright star whose hot core has used most of its hydrogen is a nova. 3. A light-year is the distance light travels in a year. 4. A small, hot, extremely dense core left after a star collapses is a white dwarf. 5. A star moving away from the Earth has a spectrum that is shifted toward red. ...
... 2. A large, bright star whose hot core has used most of its hydrogen is a nova. 3. A light-year is the distance light travels in a year. 4. A small, hot, extremely dense core left after a star collapses is a white dwarf. 5. A star moving away from the Earth has a spectrum that is shifted toward red. ...
A Star is Born!
... • Luminosity classes in an HR diagram (I through V) are based on the evolutionary phase of a star — whether it is a dwarf, subgiant, giant, or supergiant • Main sequence → Subgiant/Red giant: From burning hydrogen in the core to burning hydrogen in a shell that surrounds an inert (i.e., non-burning) ...
... • Luminosity classes in an HR diagram (I through V) are based on the evolutionary phase of a star — whether it is a dwarf, subgiant, giant, or supergiant • Main sequence → Subgiant/Red giant: From burning hydrogen in the core to burning hydrogen in a shell that surrounds an inert (i.e., non-burning) ...
Life Cycles of Stars
... megatons/second • Let’s relate that to human scales. What would that be at one kilometer distance? • 77 x 1015 tons/(150 x 106km)2 = 3 tons • Picture a truckload of explosives a km away giving off a one-second burst of heat and light to rival the Sun ...
... megatons/second • Let’s relate that to human scales. What would that be at one kilometer distance? • 77 x 1015 tons/(150 x 106km)2 = 3 tons • Picture a truckload of explosives a km away giving off a one-second burst of heat and light to rival the Sun ...
mass per nucleon
... core Helium burning (Helium Flash) shell Helium burning (double-shell burning red giant) planetary nebula white dwarf ...
... core Helium burning (Helium Flash) shell Helium burning (double-shell burning red giant) planetary nebula white dwarf ...
Unit 8 Astronomy
... the sun. This greater internal pressure causes fusion reactions to occur __________. This causes the largest stars to burn their quickly quickly fuel, and eventually run out, much more ______________. lives Larger stars live shorter _____________. Bigger stars are brighter and hotter due to the rapi ...
... the sun. This greater internal pressure causes fusion reactions to occur __________. This causes the largest stars to burn their quickly quickly fuel, and eventually run out, much more ______________. lives Larger stars live shorter _____________. Bigger stars are brighter and hotter due to the rapi ...
Lecture 15 - Deaths of Stars, Supernovae
... Determining the age of a star cluster • Imagine we have a cluster of stars that were all formed at the same time, but have a variety of different masses • Using what we know about stellar evolution is there a way to determine the age of the star cluster? ...
... Determining the age of a star cluster • Imagine we have a cluster of stars that were all formed at the same time, but have a variety of different masses • Using what we know about stellar evolution is there a way to determine the age of the star cluster? ...
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.