Nebulae
... The more massive the protostar, the more rapidly it evolves • Greater mass, contracts and heats more rapidly, and hydrogen fusion begins earlier • Greater mass, greater pressure and temperature in the core • If protostar less than 0.08 Msun, it can never develop the temperature and pressure to star ...
... The more massive the protostar, the more rapidly it evolves • Greater mass, contracts and heats more rapidly, and hydrogen fusion begins earlier • Greater mass, greater pressure and temperature in the core • If protostar less than 0.08 Msun, it can never develop the temperature and pressure to star ...
Chapter 16 Lesson 2: What is a Star
... Ribbons of gas called prominence leap out of the chromosphere that can also erupt like a volcano. 1. This is a solar flare which can last for minutes or hours. V. The Life of Stars a. New stars form in a nebula which is a cloud of dust and gas pulled together by gravity. 1. The temperature rises, hy ...
... Ribbons of gas called prominence leap out of the chromosphere that can also erupt like a volcano. 1. This is a solar flare which can last for minutes or hours. V. The Life of Stars a. New stars form in a nebula which is a cloud of dust and gas pulled together by gravity. 1. The temperature rises, hy ...
AN INTRODUCTION TO ASTRONOMY Dr. Uri Griv Department of Physics, Ben-Gurion University
... R is the radius of a star. On the other hand, L = f · (4πr2 ) → T = (f r2 /R2 σ)1/4 • The basic idea of UBV Photometry is to measure the proportions of radiant energy put out by a thermal body at ultraviolet (U), blue (B), and visual (V) wavelength • fV /fB = function of T fB /fU = function of T • I ...
... R is the radius of a star. On the other hand, L = f · (4πr2 ) → T = (f r2 /R2 σ)1/4 • The basic idea of UBV Photometry is to measure the proportions of radiant energy put out by a thermal body at ultraviolet (U), blue (B), and visual (V) wavelength • fV /fB = function of T fB /fU = function of T • I ...
HR DIAGRAM REPORT FORM
... Using the enclosed graph sheets and the background handout, complete the following plots. Graphs – 10 pts each Questions – 3 pts each A. Plot an H-R diagram for the brightest stars from table 10.1. B. Plot an H-R diagram for the closest stars from table 10.2. 1. Which type of star is most common on ...
... Using the enclosed graph sheets and the background handout, complete the following plots. Graphs – 10 pts each Questions – 3 pts each A. Plot an H-R diagram for the brightest stars from table 10.1. B. Plot an H-R diagram for the closest stars from table 10.2. 1. Which type of star is most common on ...
chapter_5_lecture_notes
... which is a small dim star that is very dense and hot. Or the supernova collapses and the pull of gravity is so strong that nothing can escape, not even light, resulting in a black ...
... which is a small dim star that is very dense and hot. Or the supernova collapses and the pull of gravity is so strong that nothing can escape, not even light, resulting in a black ...
Telephone Quizzes for ASTR 200 1999 Revision
... is the same as that of the Sun as mass does not affect the lifetime of a star. is shorter than that of the Sun since there is less fuel to burn. is longer than that of the Sun because the star generates energy (uses fuel) at a very slow rate. cannot be discussed as such a star is too small to genera ...
... is the same as that of the Sun as mass does not affect the lifetime of a star. is shorter than that of the Sun since there is less fuel to burn. is longer than that of the Sun because the star generates energy (uses fuel) at a very slow rate. cannot be discussed as such a star is too small to genera ...
Geometry Questions
... 1. What is the acceleration due to gravity on the surface of a white dwarf? Let the mass of a white dwarf by approximately 1 solar mass, or 2.0 x 1030 kg, and its radius be approximately that of Earth or 6.4 x 106 m. (J63) 2. What is the acceleration due to gravity on the surface of a neutron star? ...
... 1. What is the acceleration due to gravity on the surface of a white dwarf? Let the mass of a white dwarf by approximately 1 solar mass, or 2.0 x 1030 kg, and its radius be approximately that of Earth or 6.4 x 106 m. (J63) 2. What is the acceleration due to gravity on the surface of a neutron star? ...
General Astrophysical Concepts: Astronomical length scales
... The event horizon or Schwarzschild radius of a black hole, the region over which it is capable of trapping light (radiation), is proportional to the black hole’s mass “A black hole has no hair” is a statement that describes the loss of identity of matter when it is swallowed by a black hole The grav ...
... The event horizon or Schwarzschild radius of a black hole, the region over which it is capable of trapping light (radiation), is proportional to the black hole’s mass “A black hole has no hair” is a statement that describes the loss of identity of matter when it is swallowed by a black hole The grav ...
Lecture 13. Black Holes - Politechnika Wrocławska
... Photons are created in the nuclear fusion cycle. They collide with other charged particles and change their direction (random walk). They also decrease their energy while walking. It takes ~10 million year to get outside. The random bouncing occurs in the radiation zone (from the core to ~70% of the ...
... Photons are created in the nuclear fusion cycle. They collide with other charged particles and change their direction (random walk). They also decrease their energy while walking. It takes ~10 million year to get outside. The random bouncing occurs in the radiation zone (from the core to ~70% of the ...
Ch12&13 Life and Death of Stars
... You’ll have two shells burning around the core -- a H shell and a He shell, but no more fusion in the core. Again, the shells do nothing for the core, but they poof out the star even larger than before. It is at this point that probably our Sun will engulf ...
... You’ll have two shells burning around the core -- a H shell and a He shell, but no more fusion in the core. Again, the shells do nothing for the core, but they poof out the star even larger than before. It is at this point that probably our Sun will engulf ...
key vocabulary - El blog del Séneca
... Revolution: The orbit of a planet or star. The Sun revolves around the Milky Way. The Earth revolves the Sun. The Moon revolves the Earth. Lunar phases: The different phases the Moon goes through in 28 days. Eclipse: It occurs when the Earth, Moon and Sun are in the same line. There are two eclipses ...
... Revolution: The orbit of a planet or star. The Sun revolves around the Milky Way. The Earth revolves the Sun. The Moon revolves the Earth. Lunar phases: The different phases the Moon goes through in 28 days. Eclipse: It occurs when the Earth, Moon and Sun are in the same line. There are two eclipses ...
Lecture 17 Review
... star is too large, the gas cloud condenses quite fast, is unstable, gets very hot, and either explodes or fragments into smaller clouds which form individual stars. A second question is, can the mass of the gas be too small. The answer is yes. If the mass of the cloud is too small it heats up from g ...
... star is too large, the gas cloud condenses quite fast, is unstable, gets very hot, and either explodes or fragments into smaller clouds which form individual stars. A second question is, can the mass of the gas be too small. The answer is yes. If the mass of the cloud is too small it heats up from g ...
Document
... The colors of the stars reveal their surface temperature. For example, a Sun-like star with a surface temperature of 6000K is yellow. Taking images of stars in a few wide-spectrum bands and taking the ratio of intensities thus can be a very CHEAP way of characterizing them. ...
... The colors of the stars reveal their surface temperature. For example, a Sun-like star with a surface temperature of 6000K is yellow. Taking images of stars in a few wide-spectrum bands and taking the ratio of intensities thus can be a very CHEAP way of characterizing them. ...
lec-life-main-sequen..
... no longer balance in the layers of the star, and the layers begin to expand or contract quickly, then the star has left the main sequence. This is Eta Carinae, where in at least one shell, on at least one occasion, pressure won. In other stars, self-gravity wins. ...
... no longer balance in the layers of the star, and the layers begin to expand or contract quickly, then the star has left the main sequence. This is Eta Carinae, where in at least one shell, on at least one occasion, pressure won. In other stars, self-gravity wins. ...
mass-luminosity relationship
... We can’t find mass for one star, but we can find an average mass for a class of stars ...
... We can’t find mass for one star, but we can find an average mass for a class of stars ...
Black Hole
... We are made of Stars! After all the Hydrogen in the star was converted to Helium, for about a Million years other elements such as Carbon And others are cooked within the Star. The Supernova then throws them out in the Faraway Sky. Thus all the elements of which our Human Bodies are made were Cook ...
... We are made of Stars! After all the Hydrogen in the star was converted to Helium, for about a Million years other elements such as Carbon And others are cooked within the Star. The Supernova then throws them out in the Faraway Sky. Thus all the elements of which our Human Bodies are made were Cook ...
The Big Bang
... 1. Where are elements that are heavier than hydrogen and helium made? 2. What do we learn from the fact that most of the galaxies are red shifted? 3. What is indicated by a star’s color? ...
... 1. Where are elements that are heavier than hydrogen and helium made? 2. What do we learn from the fact that most of the galaxies are red shifted? 3. What is indicated by a star’s color? ...
Components of the Milky Way
... Conclude: massive stars are short lived, but for most stars hydrogen burning lifetime is long compared to formation time† scale. ASTR 3730: Fall 2003 ...
... Conclude: massive stars are short lived, but for most stars hydrogen burning lifetime is long compared to formation time† scale. ASTR 3730: Fall 2003 ...
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.