Chapter 21
... Betelgeuse a red supergiant, with about 20 times the mass and 800 times the radius of the Sun, so huge that it could easily contain the orbits of Mercury, Venus, Earth, Mars & Jupiter. It will probably explode as a supernova at some point within the next 100,000 years. Even at its relatively remote ...
... Betelgeuse a red supergiant, with about 20 times the mass and 800 times the radius of the Sun, so huge that it could easily contain the orbits of Mercury, Venus, Earth, Mars & Jupiter. It will probably explode as a supernova at some point within the next 100,000 years. Even at its relatively remote ...
Astronomy Lecture Notes: Stellar Nomenclature I Introduction
... c. Apparent Magnitudes i. Apparent magnitude is a code for brightness ii. Established visually by Hipparcos around 140 B.C.E. iii. Now measured using solid state photometers iv. A backward scale with the brightest star represented by the lowest number v. The brightest star in the entire sky is Siriu ...
... c. Apparent Magnitudes i. Apparent magnitude is a code for brightness ii. Established visually by Hipparcos around 140 B.C.E. iii. Now measured using solid state photometers iv. A backward scale with the brightest star represented by the lowest number v. The brightest star in the entire sky is Siriu ...
ASTR 1101-001 Spring 2008 - Louisiana State University
... Terminology used throughout Chapter 20 ...
... Terminology used throughout Chapter 20 ...
A Brief History of History
... under gravity formed the first galaxies and that the stars inside these clouds were formed later by the same process on a smaller scale. Stars come next A star is a ball of super-hot gas balanced between the twin tendencies to collapse under its own gravity, and the outward pressure of radiation ene ...
... under gravity formed the first galaxies and that the stars inside these clouds were formed later by the same process on a smaller scale. Stars come next A star is a ball of super-hot gas balanced between the twin tendencies to collapse under its own gravity, and the outward pressure of radiation ene ...
–1– Homework 4 Solutions 1. Fun physics with mean molecular
... b.Would a pure helium balloon float in the atmosphere of Jupiter? The atmosphere of Jupiter is 90% molecular Hydrogen and 10% Helium (by number, not weight). Calculate the net force on the balloon (you will have to look up the mass and radius of Jupiter) as a function of the surrounding atmospheric ...
... b.Would a pure helium balloon float in the atmosphere of Jupiter? The atmosphere of Jupiter is 90% molecular Hydrogen and 10% Helium (by number, not weight). Calculate the net force on the balloon (you will have to look up the mass and radius of Jupiter) as a function of the surrounding atmospheric ...
lecture20
... • A cloud of hydrogen gas began to gravitationally collapse. • As more gas fell in, it’s potential energy was converted into thermal energy. • Eventually the in-falling gas was hot enough to ignite nuclear fusion in the core. • Gas that continued to fall in helped to establish gravitational equilibr ...
... • A cloud of hydrogen gas began to gravitationally collapse. • As more gas fell in, it’s potential energy was converted into thermal energy. • Eventually the in-falling gas was hot enough to ignite nuclear fusion in the core. • Gas that continued to fall in helped to establish gravitational equilibr ...
On the importance of nucleation for the formation of quark cores
... • Given a certain stellar mass, the presence of a deconfined core can, e.g., lead to a different radius in comparison with a purely hadronic star, making it even more compact. • Hybrid stars can be powerful particle accelerators due to their intense magnetic fields, as well as natural “laboratories ...
... • Given a certain stellar mass, the presence of a deconfined core can, e.g., lead to a different radius in comparison with a purely hadronic star, making it even more compact. • Hybrid stars can be powerful particle accelerators due to their intense magnetic fields, as well as natural “laboratories ...
Origins of the Universe
... • This means the universe is expanding • If something is expanding it must have come from somewhere. • That somewhere is the Big Bang ...
... • This means the universe is expanding • If something is expanding it must have come from somewhere. • That somewhere is the Big Bang ...
EX - Uplift North Hills Prep
... Massive stars have greater gravity so equilibrium is reached at a higher temperature at which the outward pressure due to radiation and the hot gas will balance the inward gravitational pressure. This means that fusion proceeds at a faster rate than in stars with lower mass – meaning that the nuclea ...
... Massive stars have greater gravity so equilibrium is reached at a higher temperature at which the outward pressure due to radiation and the hot gas will balance the inward gravitational pressure. This means that fusion proceeds at a faster rate than in stars with lower mass – meaning that the nuclea ...
CHAPTER 12—STELLAR EVOLUTION
... b. hydrogen fusion combined 4 hydrogen nuclei to form 1 helium nucleus. c. pressure does not depend on temperature in degenerate matter. d. the lower limit represents when the radius of the star would be zero. e. there is a minimum temperature for hydrogen fusion. 2. There is a mass-luminosity relat ...
... b. hydrogen fusion combined 4 hydrogen nuclei to form 1 helium nucleus. c. pressure does not depend on temperature in degenerate matter. d. the lower limit represents when the radius of the star would be zero. e. there is a minimum temperature for hydrogen fusion. 2. There is a mass-luminosity relat ...
Teacher`s Guide Understanding: The Universe
... 1. Discuss why some scientists were uneasy about the idea of an expanding universe. 2. Astronomer Wendy Freedman's observations of Cepheid variable stars in another galaxy indicated that the age of the universe is about eight to twelve billion years. Why did her discovery cause such a debate among a ...
... 1. Discuss why some scientists were uneasy about the idea of an expanding universe. 2. Astronomer Wendy Freedman's observations of Cepheid variable stars in another galaxy indicated that the age of the universe is about eight to twelve billion years. Why did her discovery cause such a debate among a ...
CHP 13
... 1. The lowest-mass stars cannot become giants because a. they do not contain helium. b. they rotate too slowly. c. they cannot heat their centers hot enough. d. they contain strong magnetic fields. e. they never use up their hydrogen. 2. A planetary nebula is a. the expelled outer envelope of a medi ...
... 1. The lowest-mass stars cannot become giants because a. they do not contain helium. b. they rotate too slowly. c. they cannot heat their centers hot enough. d. they contain strong magnetic fields. e. they never use up their hydrogen. 2. A planetary nebula is a. the expelled outer envelope of a medi ...
The Death of Stars
... 1. The lowest-mass stars cannot become giants because a. they do not contain helium. b. they rotate too slowly. c. they cannot heat their centers hot enough. d. they contain strong magnetic fields. e. they never use up their hydrogen. 2. A planetary nebula is a. the expelled outer envelope of a medi ...
... 1. The lowest-mass stars cannot become giants because a. they do not contain helium. b. they rotate too slowly. c. they cannot heat their centers hot enough. d. they contain strong magnetic fields. e. they never use up their hydrogen. 2. A planetary nebula is a. the expelled outer envelope of a medi ...
Nebular Theory worksheet 2017
... further proposed that our solar system was once a star surrounded by a dust cloud. It is currently theorized that our solar system (and others like it) formed from a collapsing nebula. A nebula is a swirling collection of gases (mostly hydrogen and helium) and dust particles (solid matter in the for ...
... further proposed that our solar system was once a star surrounded by a dust cloud. It is currently theorized that our solar system (and others like it) formed from a collapsing nebula. A nebula is a swirling collection of gases (mostly hydrogen and helium) and dust particles (solid matter in the for ...
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.