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Astronomy Study Guide
Astronomy Study Guide

... Apparent brightness—the brightness of a star as seen from Earth Absolute brightness—a star’s brightness as if it were a standard distance from Earth Constellation—an imaginary pattern of stars (example—Orion) Hertzsprung - Russell diagram (H-R diagram)—a graph of stars showing surface temperature on ...
November 2005 - Otterbein University
November 2005 - Otterbein University

... stored heat, not by nuclear reactions • core continues to cool and contract • Temperature: 100  106 K at core; 50,000 K at surface • Size ~ Earth • Density: a million times that of Earth – 1 cubic cm has 1000 kg of mass! ...
Lab 5 Takehome
Lab 5 Takehome

... mean  redder  colors.    The  color  of  a  star  is  determined  mainly  by  the  temperature  of   its  surface.    Hotter  stars  are  bluer,  cooler  stars  are  redder.   ...
14.5 Yellow Giants and Pulsating Stars Variable Stars Not all stars
14.5 Yellow Giants and Pulsating Stars Variable Stars Not all stars

... R diagram shown in figure 14.15. In this region the star's opacity “puts a lid on” light coming out of the star's core. The atmosphere then expands and cools until its opacity declines enough to let the light out. The atmosphere compresses and heats, and the cycle repeats. A star that assumes these  ...
The Death of a Star - hrsbstaff.ednet.ns.ca
The Death of a Star - hrsbstaff.ednet.ns.ca

... due to the gravitational attraction of the particles that comprise them. For those who are not aware of this yet, outer space is not really totally a vacuum (although it may sometimes be approximated as such). Rather, it is made up of gas and dust known collectively as the interstellar medium or ISM ...
Death of Stars notes
Death of Stars notes

... debris cloud of hot gas and dust. • Scientists had evidence of such dust formation, but couldn’t be sure that the dust wasn’t destroyed in the “rebound” shock wave when the expanding supernova remnant collided with the interstellar medium of thinly scattered material, creating another shock wave tra ...
doc - University of Texas Astronomy
doc - University of Texas Astronomy

... then see spectral lines in its optical “afterglow.” The resulting Doppler shift was a redshift and it was enormous. As we’ll see later, because the universe is expanding, redshift can be used to get distance. Resulting distance for this gamma ray burst was 2 billion parsecs! By now we have seen ~10 ...
here
here

... Extinction in the Diffuse ISM •  UV – 220nm bump and short wavelength rise – quite variable •  Optical to Near-IR fairly linear, power law, less variable, DIBs, maximum of interstellar polarization curve •  Mid-IR: Silicate absorption bands at 10 and 20um. Polarized so (some) silicate grains are non ...
Interview With a White Dwarf – Teacher Guide
Interview With a White Dwarf – Teacher Guide

... “Our galaxy, by conservative estimates, contains 100 billion stars. The small number of stars we can see at night are the nearby stars in our tiny neighborhood of our galaxy. Stars are not eternal, but live long lives compared to our lifetime. Over time they change. Just like you can look at a famil ...
Lecture 5: Light as a tool
Lecture 5: Light as a tool

... • Hipparcos mission (European Space Agency) measured the stellar parallax of roughly 100,000 stars with precision of a few milli-arcseconds. So, it can measure distance of star up to 1,000 light-years away… ...
The Stars
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... HR Diagram are cool but extremely bright stars. • These are the supergiants, stars that some day will supernova. • They eventually might become black holes. ...
hw5
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... combine to form basic amino acids and building blocks of DNA present in life on Earth. At a time when the Earth’s atmosphere lacked ozone’s protection from ultraviolet light, the oceans provided a safe region that UV can’t penetrate. p. 458 RQ# 9 How does intelligence make a creature more likely to ...
How do the most massive galaxies constrain theories of
How do the most massive galaxies constrain theories of

... Why are red galaxies red? o CDM models produce enough old, massive galaxies. the problem is a continuous ‘trickle’ of star formation o there must be some process that shuts off star formation after galaxies have become massive o this process must be rapid, and seems to be connected with the presenc ...
The Universe
The Universe

... galaxies where cool gas is not so depleted. Spiral galaxies, like the Milky Way, only produce new generations of stars as long as they have dense molecular clouds of interstellar hydrogen in their spiral arms. Elliptical galaxies are already largely devoid of this gas, and so form no new stars. The ...
The Universe
The Universe

... galaxies where cool gas is not so depleted. Spiral galaxies, like the Milky Way, only produce new generations of stars as long as they have dense molecular clouds of interstellar hydrogen in their spiral arms. Elliptical galaxies are already largely devoid of this gas, and so form no new stars. The ...
HST Paα Survey of the Galactic Center – Seeking the Missing
HST Paα Survey of the Galactic Center – Seeking the Missing

... young massive star clusters. As we mentioned previously, they are evolved massive stars with ages of a few Myr. Studying their origin can help us understand the star formation mode within the GC. Two third of these field Paα stars are located on the positive Galactic longitude side of Sgr A* and are ...
We Are Stardust: Synthesis of the Elements Essential for Life Aparna
We Are Stardust: Synthesis of the Elements Essential for Life Aparna

... reveals important clues about the creation of the universe. First, we have seen that the Sun’s central temperature is about 15 million degrees, at which temperatures only hydrogen can be burned. Therefore, in order to be stable for over 3 billion years, the Sun must be made up of mostly hydrogen. Se ...
Low Mass
Low Mass

... • Double-shell burning causes strong stellar winds, star expels all of its outer layers • Expelled material, rich in heavy elements such as carbon and silicon, forms planetary nebula. • ~60% of mass is lost in planetary nebula • The process of expelling material and forming the planetary nebula occu ...
talk / PPT / 1.6 MB
talk / PPT / 1.6 MB

... Are there still at least as many baryons to be found in the Milky Way? ...
Astronomy Assignment
Astronomy Assignment

... ‘We are all just Star Stuff”- Carl Sagan, truer words have never been spoken. Every atom of our bodies was formed in the core of some long dead star. But how and where and why? In order to answer these questions we must understand the stars themselves and the clouds from which they arise and often a ...
Stars, Galaxies, and the Universe Section 1 Section 1
Stars, Galaxies, and the Universe Section 1 Section 1

... • Most stars have several types of actual motion. • Stars move across the sky (seen only for close stars). • Some stars may revolve around another star. • Stars either move away from or toward our solar system. ...
Stellar Physics Lecture 1
Stellar Physics Lecture 1

... – The narrow band of stars scattered close to the solid line. – Most stars occur along this band – an indication that this is where stars spend most of their lives. For this reason, it is known as the Main Sequence. ...
1) The following questions refer to the HR diagram
1) The following questions refer to the HR diagram

... A) it amplifies the contrast with red giants. B) they are both very hot and very small. C) they are supported by electron degeneracy pressure. D) they are the end-products of small, low-mass stars. E) they are the opposite of black holes. 22) What happens to the surface temperature and luminosity wh ...
6 - In the Beginning: Science and Genesis 1-11
6 - In the Beginning: Science and Genesis 1-11

... “The complete birth of a star has never been observed. The principles of physics demand some special conditions for star formation and also for a long time period. A cloud of hydrogen gas must be compressed to a sufficiently small size so that gravity dominates.” ...
Unit 1
Unit 1

... to the main sequence, stay for a while, and eventually move through giant stages before becoming white dwarfs • Higher mass stars move rapidly off the main sequence and into the giant stages, eventually exploding in a supernova ...
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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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