lecture 27 nuclar fusion in stars
... A star must have at least 10% of the sun’s mass in order for fusion to start. If the mass is much more than 100 times the sun’s mass, it will blow apart very quickly. In between, a star’s life cycle is determined primarily by its mass. ¤ Stars ...
... A star must have at least 10% of the sun’s mass in order for fusion to start. If the mass is much more than 100 times the sun’s mass, it will blow apart very quickly. In between, a star’s life cycle is determined primarily by its mass. ¤ Stars ...
Main Sequence Star
... STEP 3. Nuclear fusion • 4 hydrogen fuse to make helium plus energy • Occurs in the core • Must be 10 mil – degrees C ...
... STEP 3. Nuclear fusion • 4 hydrogen fuse to make helium plus energy • Occurs in the core • Must be 10 mil – degrees C ...
File
... 24) What shape is the Milky Way? 25) What is the local group? 26) How many stars are in the Milky Way? 27) Approximately how big is the Milky Way 28) The largest known galaxy is what type of galaxy? 29) What is a light year? Section 4 30) What is cosmology? 31) How old is the universe? 32) What is t ...
... 24) What shape is the Milky Way? 25) What is the local group? 26) How many stars are in the Milky Way? 27) Approximately how big is the Milky Way 28) The largest known galaxy is what type of galaxy? 29) What is a light year? Section 4 30) What is cosmology? 31) How old is the universe? 32) What is t ...
Stellar Evolution Notes
... formed iron, no more reactions can occur, and the core violently collapses in on itself Supernova ...
... formed iron, no more reactions can occur, and the core violently collapses in on itself Supernova ...
Stellar Evolution
... • In the case of the Sun (or any 1Mo star) the gradual increase in radius and luminosity will continue for another 5 billion years. • While hydrogen fusion is the dominant energy source, there is a useful thermostat operating. If the Sun contracted and heated up, the fusion rates would increase and ...
... • In the case of the Sun (or any 1Mo star) the gradual increase in radius and luminosity will continue for another 5 billion years. • While hydrogen fusion is the dominant energy source, there is a useful thermostat operating. If the Sun contracted and heated up, the fusion rates would increase and ...
New Directions in Star Cluster Research
... Stars must evolve (as they release energy) - changes in structure and/or chemical composition Death of a star can occur in 2 ways (a) Violation of first condition - self gravity (breakup of star scattering material into space) (b) Violation second condition - internally supplied radiation (exhaustio ...
... Stars must evolve (as they release energy) - changes in structure and/or chemical composition Death of a star can occur in 2 ways (a) Violation of first condition - self gravity (breakup of star scattering material into space) (b) Violation second condition - internally supplied radiation (exhaustio ...
stars concept review
... b. a large cloud of gas and dust in space where stars are born c. a shrinking, spinning region in space with a central concentration of matter d. a large explosion on a star that makes it brighter e. an object so dense that even light cannot escape its gravity ...
... b. a large cloud of gas and dust in space where stars are born c. a shrinking, spinning region in space with a central concentration of matter d. a large explosion on a star that makes it brighter e. an object so dense that even light cannot escape its gravity ...
April 1st
... • Not enough mass for fusion • Minimum mass of gas need for fusion is 0.08 solar masses (80 times the mass of Jupiter) ...
... • Not enough mass for fusion • Minimum mass of gas need for fusion is 0.08 solar masses (80 times the mass of Jupiter) ...
Review Day
... stars held together by gravity. There are 3 types of galaxies: Spiral: Pinwheel shape with stars on the arms and gas and dust clustered in the center. Thought that a black hole is in center. ...
... stars held together by gravity. There are 3 types of galaxies: Spiral: Pinwheel shape with stars on the arms and gas and dust clustered in the center. Thought that a black hole is in center. ...
The Life Cycle of Stars
... When nuclear fusion stops->the star’s core begins to collapse due to its own gravity->the outer layers of the star drift away->hot core is all that remains (white dwarf)->cools down, all that remains is dark, cold matter (black dwarf) For stars tens of times more massive than the sun, the outer laye ...
... When nuclear fusion stops->the star’s core begins to collapse due to its own gravity->the outer layers of the star drift away->hot core is all that remains (white dwarf)->cools down, all that remains is dark, cold matter (black dwarf) For stars tens of times more massive than the sun, the outer laye ...
How do stars form?
... • Shows relationships among size, temperature and brightness (luminosity or magnitude). • Larger, stable stars are hotter and brighter. • Large, hot stars burn out faster than smaller, cooler stars. ...
... • Shows relationships among size, temperature and brightness (luminosity or magnitude). • Larger, stable stars are hotter and brighter. • Large, hot stars burn out faster than smaller, cooler stars. ...
Origin of Elements - Madison Public Schools
... – almost exactly what is observed in the visible universe. ...
... – almost exactly what is observed in the visible universe. ...
ppt - Slides by Prof Christian
... Expansion onto the Giant Branch Expansion and surface cooling during the phase of an inactive He core and a H- burning shell ...
... Expansion onto the Giant Branch Expansion and surface cooling during the phase of an inactive He core and a H- burning shell ...
worksheet
... If the luminosity (power output) of the sun is 3.9 x 1026W, work out how much Hydrogen the sun 'burns' each second, and how much the equivalent in coal would be. ...
... If the luminosity (power output) of the sun is 3.9 x 1026W, work out how much Hydrogen the sun 'burns' each second, and how much the equivalent in coal would be. ...
The HR Diagram and Stars Worksheet
... 2. Use your book to add the following information to the H-R diagram. a. Page 622 – Add the Spectral Class below the temperatures. b. Page 626 – Use colored pencils to add and label the band that represents Main Sequence stars. c. Page 626 – Use colored pencils to label the following areas: Blue Gia ...
... 2. Use your book to add the following information to the H-R diagram. a. Page 622 – Add the Spectral Class below the temperatures. b. Page 626 – Use colored pencils to add and label the band that represents Main Sequence stars. c. Page 626 – Use colored pencils to label the following areas: Blue Gia ...
Unit 1
... – Most are giants (Yellow Giants) – Instability comes from partial absorption of radiation in the interior of the star • Helium absorbs radiation, and the outer layers of the star get pushed away from core • As the star expands, the density decreases, letting photons escape • Outer layers head back ...
... – Most are giants (Yellow Giants) – Instability comes from partial absorption of radiation in the interior of the star • Helium absorbs radiation, and the outer layers of the star get pushed away from core • As the star expands, the density decreases, letting photons escape • Outer layers head back ...
AST 301 Introduction to Astronomy - University of Texas Astronomy
... to about ½ AU, and it will become more than 1000 times more luminous than it is now. Life will not be pleasant on Earth. The core of the Sun will be mostly helium, and will continue to contract and heat up. When the temperature in the core reaches about 108 K (about 1 billion years after the Sun lea ...
... to about ½ AU, and it will become more than 1000 times more luminous than it is now. Life will not be pleasant on Earth. The core of the Sun will be mostly helium, and will continue to contract and heat up. When the temperature in the core reaches about 108 K (about 1 billion years after the Sun lea ...
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.