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Lesson 4. Wiens and Stefans Laws
Lesson 4. Wiens and Stefans Laws

... The ratio of the power output of two stars can be used to calculate the ratio of the diameters of the stars. (If one of those starts has a known diameter e.g the Sun the diameters of the other star can be determined) ...
How is the Potential Energy Released
How is the Potential Energy Released

... The accretion rate of, ~ 0.1 the Eddington limited accretion rate falls onto a surface area only 10-3 of the star ! So the local flux generated >> Eddington limit For such accretion to persist, the radiation cannot escape back up the accretion funnel (remember the incoming material is interacting wi ...
ph507lecnote06
ph507lecnote06

... temperature. Luminosity falls but temperature is constant. Later, or for high-mass stars, radiative energy transport becomes effective – central temperature rises – luminosity increases slightly as surface temperature rises and contraction continues. Brown Dwarfs: Failed Stars • Stars between 1/100 ...
supernova remnants
supernova remnants

... How is mass and energy distributed in the ejecta? What was the mechanism of the supernova explosion? What and (how much) elements were formed in the explosion, and how? What are the characteristics of the compact stellar remnant? Shock physics: How is energy distributed between electrons, ions, and ...
Publisher: Emily Barrosse Acquisitions Editor: Kelley Tyner
Publisher: Emily Barrosse Acquisitions Editor: Kelley Tyner

... Though the details can differ, all stars containing less than about ten times the Sun’s mass will have the same fate. As fusion exhausts the hydrogen in their centers, their internal pressure will diminish. Gravity will pull the core in, and the core will heat up again. Hydrogen will begin “burning” ...
Stellar Physics
Stellar Physics

... the diagram, Figure 1.2). Hence they cannot absorb photons in the Balmer series and so the absorption lines are feint. On the other hand, if a star is hot, there will be lots of violent collisions exciting electrons into higher energy levels or even knocking t hem out of atoms completely to produce ...
Titelseite
Titelseite

Basics of Astrophysics
Basics of Astrophysics

... The    speckle  pattern  change  rapidly,  if  v  is  the  speed  of  the  wind  the  timescale  can  be   roughly  estimated  by  t  =  r/v  where  r  is  the  size  of  the  cell  causing  the  speckle.   With  a  rather   ...
Lyman-α: The Many Applications and Challenges of This Powerful
Lyman-α: The Many Applications and Challenges of This Powerful

... parts per million (ppm) in the gas located within about 300 light-years of the Sun. At further distances, the large range in interstellar gas D/H ratios between 4 and 23 ppm can be explained by different amounts of D gas depletion onto dust grains along these lines of sight. This technique has allow ...
AST1100 Lecture Notes
AST1100 Lecture Notes

... to about 10R⊙ . Giant stars fall in the range between 10R⊙ to about 100R⊙ whereas super giants may have radii of several 100 solar radii. The masses of stars range from 0.08M⊙ for the least massive stars up to about 100M⊙ for the most massive stars. We will later discuss theoretical arguments expla ...
Project 4: The HR diagram. Open clusters
Project 4: The HR diagram. Open clusters

... regions. This tells you that there is some physical relationship between the luminosity and temperature of a star. From the figure one sees that most stars fall along a diagonal strip from high temperature, high luminosity stars to low temperature, low luminosity stars. These are the main sequence s ...
Student Handout - Mr. vallee`s Class Site
Student Handout - Mr. vallee`s Class Site

... and ________ moved through the sky in a different way than the stars. They noticed that, over time, these objects appeared to move with respect to the __________________________. 10. Because of the ___________________________ and its __________ around the Sun, it is convenient to divide the constell ...
Exam 03
Exam 03

... greater sunspot formation followed by periods of reduced sunspot activity. ...
Exoplanets Properties of the host stars Characterization of the
Exoplanets Properties of the host stars Characterization of the

... –  A good knowledge of the properties of the stars hosting exoplanets is fundamental to improve the accuracy of exoplanet measurements –  Accurate determination of stellar masses and radii are required to derive masses and radii of the planets detected with the Doppler and transit methods, respectiv ...
Lecture12
Lecture12

Li-cai Deng
Li-cai Deng

... The Future of Galactic structure In the Milky Way, we have the opportunity to learn the whole history of one galaxy instead of comparing snapshots of many. It is only now that we have large surveys of the whole sky that we are able to comprehend the Milky Way as a whole. Unlike external galaxies, t ...
light year
light year

... • Simply put, celestial bodies are so ginormous that it’s difficult to measure things. • We’ll learn a lot of the measurements throughout the course, but we’ll start with two important things: – Scientific Notation (in general). – The Light Year, the Parsec, and the Astronomical Unit. ...
Chapter21
Chapter21

... 1. The Kinds of Binary Stars In most other introductory astronomy textbooks, binary stars are covered in a piecemeal fashion in several different chapters. There are several reasons why I decided to cover binary stars in a single coherent chapter. First, most stars are in binary or multiple systems, ...
Introduction to Galaxies - West Jefferson Local Schools
Introduction to Galaxies - West Jefferson Local Schools

the printable Observing Olympics Object Info Sheet in pdf
the printable Observing Olympics Object Info Sheet in pdf

... nebula has been expanding at a constant rate of 10 milli-arcseconds a year, then it would take 1000 ± 260 years to reach a diameter of 20 arcseconds. This may be an upper limit to the age, because ejected material will be slowed when it encounters material ejected from the star at earlier stages of ...
Space and Time The Issue of the Beginning and the End
Space and Time The Issue of the Beginning and the End

... direction. Using Einstein’s equations, in 1922 the Russian mathematician Alexander Friedmann showed that such a universe can not be static. It must expand or contract. In 1929 the American astronomer Edwin Hubble found that the universe is indeed expanding. This in turn implies that it must have had ...
Galaxy Notes File
Galaxy Notes File

... Types of Galaxies = Spirals Spirals are classified according to how tightly or loosely wound the arms are. The brightness of the central nucleus is correlated to the tightness of the arm. The galaxies M 104 (below) and M 51 (right) respectively show tightly and loosely wounds. Notice the effects of ...
Letot STELLAR EVOLUTION By Kyle Letot Grade Level: 6
Letot STELLAR EVOLUTION By Kyle Letot Grade Level: 6

... together by the force of gravity. Balloons are also made out of gas and held together by a force of gravity, in this case it is an elastic covering. In this practical lab we will use balloons to explain the concept of stars and how they work in the Universe. Before we begin, I will put a little rice ...
Chapter 11 Surveying the Stars How do we measure stellar
Chapter 11 Surveying the Stars How do we measure stellar

Rotation in the ZAMS: Be and Bn stars
Rotation in the ZAMS: Be and Bn stars

... Figure 3a shows the apparent V=7 magnitude limited counts of dwarf Be stars relative to dwarf B stars. There is an apparent lack of dwarf Be stars cooler than spectral type B7. This could be due to genuine Be stars whose discs are minute and/or too cool for the Hα emission be detectable and/or, to f ...
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Future of an expanding universe

Observations suggest that the expansion of the universe will continue forever. If so, the universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario is popularly called the Big Freeze.If dark energy—represented by the cosmological constant, a constant energy density filling space homogeneously, or scalar fields, such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space—accelerates the expansion of the universe, then the space between clusters of galaxies will grow at an increasing rate. Redshift will stretch ancient, incoming photons (even gamma rays) to undetectably long wavelengths and low energies. Stars are expected to form normally for 1012 to 1014 (1–100 trillion) years, but eventually the supply of gas needed for star formation will be exhausted. And as existing stars run out of fuel and cease to shine, the universe will slowly and inexorably grow darker, one star at a time. According to theories that predict proton decay, the stellar remnants left behind will disappear, leaving behind only black holes, which themselves eventually disappear as they emit Hawking radiation. Ultimately, if the universe reaches a state in which the temperature approaches a uniform value, no further work will be possible, resulting in a final heat death of the universe.
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