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Astronomy Facts
Astronomy Facts

... The distance to our nearest large galaxy, Andromeda (2.9 million light years), is about 29- times the Milky Way’s diameter (100 thousand light years). If your fist were the Milky Way, hold it high over your head - Andromeda would be another fist-sized galaxy at your feet!! ...
Protostar formation
Protostar formation

... Thus, the number of p-p cycle per second in the sun is: Total power/energy per cycle=L/E=3.9x1026/4.1x10-12=9.5x1037 reactions/second Since each p-p cycle requires 4 protons, the number of protons used every second in the sun is: np=4x9.5x1037 =3.8x1038 protons/second How many protons are in the sun ...
Lecture 11, PPT version
Lecture 11, PPT version

... Hydrogen lines, and the very coolest stars show strong lines due to molecules (like titanium oxide). This is really is a temperature effect, it is not reflective of different chemical composition for the different stars! ...
Life Cycle of a Star
Life Cycle of a Star

... White dwarfs are extremely small stars with huge densities. ...
Sizing Up The Universe
Sizing Up The Universe

... period of variability by observing a number of them in the Small Magellanic Cloud. They were all at approximately the same distance, so their relative luminosity as a function of their period of variability could be determined. From 1923 to 1924 Edwin Hubble (1889–1953) observed the Andromeda galaxy ...
every star in the cluster.
every star in the cluster.

... giants, continually forming from evolving stars near the turnoff. But there were originally many stars that were even more massive, that became red giants for a time, and that have moved on to a different final form. The cluster contains a huge number of ‘stellar remnants.’ [Details to follow!] ...
CONSTELLATION TUCANA, THE TOUCAN
CONSTELLATION TUCANA, THE TOUCAN

... is a dwarf galaxy that is one of the nearest neighbors to the Milky Way galaxy at a distance of 210,000 light-years. Though it probably formed as a disk shape, tidal forces from the Milky Way have distorted it. Along with the Large Magellanic Cloud, it lies within the Magellanic Stream, a cloud of g ...
Why are Binary Stars so Important for the Theory
Why are Binary Stars so Important for the Theory

... During the past year, two new southern dwarf galaxies were discovered on ESO Schmidt plates. The first object, in the constellation Phoenix, was first believed to be a distant globular cluster (cf. Messenger No. 4, March 1976), but recent observations by American astronomers at the Gerro Tololo Inte ...
Lives of stars
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... 3. Do these pair(s) of stars have same stellar classification? explain 4. Which two stars have same luminosity? 5. Do these pair(s) have same stellar classifications? explain 6. Which letter is most similar to the current sun’s location n the diagram? 7. When the sun starts to die, the sun will star ...
Lab 7: Galaxies
Lab 7: Galaxies

... higher density areas have more mass, and therefore more gravity, which affects the velocity of the stars and gas going into the wave. As the matter leaves the density wave, its velocity returns to normal. The spiral arms are visible because of the intense star formation and young hot OB class stars ...
Star Stuff
Star Stuff

... - divides the light up into its colors (wavelengths) - use a smaller range of wavelengths than entire EM spectrum because instrumentation is different ...
Chapter 29 Review
Chapter 29 Review

... What causes the dark bands observed in a solar spectrum? 1. the emission of specific elements 2. different chemical elements which absorb light at specific wavelengths 3. highly compressed, glowing gas 4. warmer gas in front of a source that emits a continuous spectrum ...
GEARS Workshop Monday - Georgia Southern University
GEARS Workshop Monday - Georgia Southern University

... our own Sun, have found a remarkable object where the nuclear reactor that once powered it has only just shut down. This star, the hottest known white dwarf, H1504+65, seems to have been stripped of its entire outer regions during its death throes leaving behind the core that formed its power plant. ...
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Handout Life of Stars

... is formed when gravity causes the dust and gas of a nebula to clump together in a process called accretion. As gravity continues to pull ever more matter inward towards the core, its temperature, pressure and density increases. If a critical temperature in the core of a protostar is reached, then nu ...
Universe 8e Lecture Chapter 17 Nature of Stars
Universe 8e Lecture Chapter 17 Nature of Stars

... Photometry and Color Ratios: Photometry measures the apparent brightness of a star. The color ratios of a star are the ratios of brightness values obtained through different standard filters, such as the U, B, and V filters. These ratios are a measure of the star’s surface temperature. Spectral Type ...
Chapter 10. Stellar Spectra
Chapter 10. Stellar Spectra

... levels. Their strength depends on the abundance of HI (neutral Hydrogen) in the n=2 (first excited state). This is a maximum at a temperature of around 10,000 K, characteristic of A stars. A stars therefore have the strongest H lines (this is, in fact, why they were called A stars). Hotter stars (O ...
Lecture 2
Lecture 2

... elements (not hot enough) • These stars eject most of their outer layers • Only the core is left, which “lights-up” the gas that the star has been ejecting – causing ...
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Hubble Space Telescope Image
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AST101_lect_12
AST101_lect_12

... • Stars generate luminosity through fusion of H into He • The lifetime of a star is proportional to the amount of fuel it has (mass) divided by the rate at which it expends the fuel (luminosity) • The lifetime τ ~ M/L • This is analogous to determining how often you have to refill the gas tank in yo ...
What are the Spectral Lines? - University of Texas Astronomy Home
What are the Spectral Lines? - University of Texas Astronomy Home

... - real knowledge only due to hard facts, e.g., laboratory science, measurements • claimed ...
Phys 100 – Astronomy (Dr. Ilias Fernini) Review Questions for
Phys 100 – Astronomy (Dr. Ilias Fernini) Review Questions for

... 39. The energy a white dwarf emits into space is a. replaced by fusion of hydrogen atoms into helium. b. replaced by fusion of helium atoms into carbon. * c. not replaced. 40. A Type I supernova is believed to occur when a. the core of a massive star collapses. b. carbon detonation occurs. * c. a wh ...
Stars - Red, Blue, Old, New pt.4
Stars - Red, Blue, Old, New pt.4

... radio waves 33 times a second. • Pulsations occur at all wavelengths--optical, X-ray, etc. • What could it be? ...
Document
Document

... The C-O core is degenerate and transports its radiation by conduction. ...
The Later Evolution of Low Mass Stars (< 8 solar masses)
The Later Evolution of Low Mass Stars (< 8 solar masses)

... The C-O core is degenerate and transports its radiation by conduction. ...
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H II region



An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.
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