Star Formation
... 4) The collapsing gas becomes a young stellar object with an accretion disk and jets 4) When the young stellar object begins fusing hydrogen into helium it becomes a true star ...
... 4) The collapsing gas becomes a young stellar object with an accretion disk and jets 4) When the young stellar object begins fusing hydrogen into helium it becomes a true star ...
Elements from Stardust
... energy, they can join together in a process called nuclear fusion. In nuclear fusion, atomic nuclei combine to form a larger nucleus, releasing huge amounts of energy in the process. Inside stars, nuclear fusion combines smaller nuclei into larger nuclei, thus creating heavier elements. For this ...
... energy, they can join together in a process called nuclear fusion. In nuclear fusion, atomic nuclei combine to form a larger nucleus, releasing huge amounts of energy in the process. Inside stars, nuclear fusion combines smaller nuclei into larger nuclei, thus creating heavier elements. For this ...
Appendix 2
... A brief history of the cosmos. Telescopes - such as the Hubble telescope - show we are surrounded by millions of galaxies. Observation shows that overall movement of the galaxies is to move away from each other. The speed of any two galaxies is greater the further they are apart. This is understood ...
... A brief history of the cosmos. Telescopes - such as the Hubble telescope - show we are surrounded by millions of galaxies. Observation shows that overall movement of the galaxies is to move away from each other. The speed of any two galaxies is greater the further they are apart. This is understood ...
Today`s Powerpoint
... Mass of end products is less than mass of 4 protons by 0.7%. Mass converted to energy. 600 millions of tons per second fused. Takes billions of years to convert p's to 4He in Sun's core. Process sets lifetime of stars. Hydrostatic Equilibrium: pressure from fusion reactions balances gravity. Sun is ...
... Mass of end products is less than mass of 4 protons by 0.7%. Mass converted to energy. 600 millions of tons per second fused. Takes billions of years to convert p's to 4He in Sun's core. Process sets lifetime of stars. Hydrostatic Equilibrium: pressure from fusion reactions balances gravity. Sun is ...
Groups of Stars
... • Compare the life of a star to the life of a human. Describe how the life stages are similar. You will need to choose the life cycle of either a lowmedium mass star OR a high mass star. ...
... • Compare the life of a star to the life of a human. Describe how the life stages are similar. You will need to choose the life cycle of either a lowmedium mass star OR a high mass star. ...
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 ...
Chapter 27 Stars and Galaxies
... matter…a WHITE DWARF ►White dwarfs shine for billions of years ...
... matter…a WHITE DWARF ►White dwarfs shine for billions of years ...
Chapter 24 Test:Stars/Galaxies
... The big bang theory of the formation and expansion of the universe is supported by the observed uniform and scaled _____. (a) shorter light wavelengths, (b) Doppler shift to blue-violet, (c) "big crunch", (d) Doppler shift to red. ...
... The big bang theory of the formation and expansion of the universe is supported by the observed uniform and scaled _____. (a) shorter light wavelengths, (b) Doppler shift to blue-violet, (c) "big crunch", (d) Doppler shift to red. ...
55-80 BIOGRAPHY_of_A STAR
... Thought Question What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion (triple alpha) starts very sharply Hint: this is a strong reaction (no neutrinos) once the temperature is hot e ...
... Thought Question What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion (triple alpha) starts very sharply Hint: this is a strong reaction (no neutrinos) once the temperature is hot e ...
Astronomy Notes
... 3. ________________________ - because of gravity the nebula collapses inward. (In the case of our Sun approximately 98% of the matter in the nebula became the star). This collapsing mass is under great pressure and heats up and is called a _____________. (This kind of temperature change is called an ...
... 3. ________________________ - because of gravity the nebula collapses inward. (In the case of our Sun approximately 98% of the matter in the nebula became the star). This collapsing mass is under great pressure and heats up and is called a _____________. (This kind of temperature change is called an ...
Four Homework Assignments
... big bang, carbon-burning, etc.) where each of the elements in the Sun or interstellar medium up to an atomic number (Z) of 26 are created. 17. In our discussion of the “ignition mass” for a given stage of thermonuclear burning, we derived a formula that seemed to work reasonably well for the main-se ...
... big bang, carbon-burning, etc.) where each of the elements in the Sun or interstellar medium up to an atomic number (Z) of 26 are created. 17. In our discussion of the “ignition mass” for a given stage of thermonuclear burning, we derived a formula that seemed to work reasonably well for the main-se ...
21_LectureOutline
... reignite very suddenly, burning off the new material. Material keeps being transferred to the white dwarf, and the process repeats, as illustrated here: ...
... reignite very suddenly, burning off the new material. Material keeps being transferred to the white dwarf, and the process repeats, as illustrated here: ...
binary stars
... nuclear collisions. More fusion would occur, and more energy would be produced. This explains the main sequence! • Fusion only occurs in the core, where the temperature and density are greatest. The rest of the star just sits there. ...
... nuclear collisions. More fusion would occur, and more energy would be produced. This explains the main sequence! • Fusion only occurs in the core, where the temperature and density are greatest. The rest of the star just sits there. ...
Key Facts
... hydrogen and helium undergoing nuclear fusion at very high temperatures, hence producing vast quantities of energy in the form of heat and light. ...
... hydrogen and helium undergoing nuclear fusion at very high temperatures, hence producing vast quantities of energy in the form of heat and light. ...
Goal: To understand how stars form.
... • 1) Local supernova – however you need to form a star to do that. • 2) Collision with another cloud of gas – this usually happens when 2 galaxies collide. • 3) Spiral arm – probably the most common. • You get a spiral density wave that shocks the gas cloud. That causes it to collapse – much like se ...
... • 1) Local supernova – however you need to form a star to do that. • 2) Collision with another cloud of gas – this usually happens when 2 galaxies collide. • 3) Spiral arm – probably the most common. • You get a spiral density wave that shocks the gas cloud. That causes it to collapse – much like se ...
Stars - TeacherWeb
... • The matter inside the star will be compressed so tightly that its atoms are compacted into a dense shell of neutrons. If the remaining mass of the star is more than about three times that of the Sun, it will collapse so completely that it will literally disappear from the universe. What is left be ...
... • The matter inside the star will be compressed so tightly that its atoms are compacted into a dense shell of neutrons. If the remaining mass of the star is more than about three times that of the Sun, it will collapse so completely that it will literally disappear from the universe. What is left be ...
star
... • After helium in the cores of lower-mass stars is gone, the stars cast off their gases exposing their cores. • The core eventually becomes a white dwarf, a hot, dense, slowly cooling sphere of carbon. • This is what is expected to happen to the Sun. ...
... • After helium in the cores of lower-mass stars is gone, the stars cast off their gases exposing their cores. • The core eventually becomes a white dwarf, a hot, dense, slowly cooling sphere of carbon. • This is what is expected to happen to the Sun. ...
giant molecular clouds
... Large, dense cluster of (yellow and red) stars in the foreground; ~ 50 million years old ...
... Large, dense cluster of (yellow and red) stars in the foreground; ~ 50 million years old ...
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.