Dense interstellar clouds are the BIRTH PLACES of stars Dark clouds alter and BEND the light from STARS behind them.
|
|
- Homer Newton
- 6 years ago
- Views:
Transcription
1 Chapter 10 Notes: Nebulae Astronomy Name: SOLUTION SET Date: 4/11 An introduction to interstellar medium A World of Dust 1. The space between stars is not completely EMPTY, but filled with very dilute GAS and DUST, producing some of the most beautiful objects in the sky. 2. We are interested in the INTERSTELLAR medium because: o o Dense interstellar clouds are the BIRTH PLACES of stars Dark clouds alter and BEND the light from STARS behind them. Use pp in your text and the video The Universe Nebulas to answer these questions. II. Three Kinds of Nebulae Name each type of nebula and describe the physical and chemical properties (temp, density, color, etc) and why they appear how they appear. A. EMISSION NEBULAE PINK IN COLOR, EMISSION PRODUCED WHEN A HOT STAR EXCITES THE GAS AROUND IT TO PRODUCE A SPECTRUM. RED, BLUE AND VIOLET BALMER LINES BLEND TO MAKE THE EMISSION SPECTRUM PINK. B. REFLECTION NEBULA DUST IN NEBULA REFLECTS STARLIGHT, ABSORPTION SPECTRUM IS BLUE. GAS PRESENT IN THE NEBULA IS NOT EXCITED TO EMIT PHOTONS SO ONLY DUST IS VISIBLE C. DARK NEBULA DENSE CLOUDS OF GAS AND DUST THAT OBSTRUCT OUR VIEW OF MORE DISTANT STARS. SHAPE OF A DARK NEBULA DEPENDS ON THE PRESENCE OR ABSENCE OF A BREEZE OR CURRENT MOST ARE ROUND, SUGGESTING A LACK OF MOTION, BUT SOME ARE TWISTED AND DISTORTED.
2 Reading Questions from Chapter 10, pg 212. RQ 1. EVIDENCE FOR INTERSTELLAR MEDIUM INTERSTELLAR EXTINCTION DUST MAKES DISTANT STARS APPEAR FAINTER THAN THEY SHOULD INTERSTELLAR REDDENING SOME O STARS APPEAR RED INSTEAD OF BLUE BECAUSE THE DUST SCATTERS THE LIGHT FROM THOSE STARS WE CAN SEE EMISSION, REFLECTION AND DARK NEBULAE RQ 2. EVIDENCE FOR GAS EMISSION NEBULAE SHOW THE EMISSION SPECTRUM OF EXCITED HYDROGEN EVIDENCE FOR DUST INTERSTELLAR EXTINCTION AND DARK NEBULAE RQ 5. BLUE PHOTONS ARE PREFERENTIALLY SCATTERED IN A DUSTY REFLECTION NEBULA, JUST LIKE BLUE PHOTONS ARE PREFERENTIALLY SCATTERED IN EARTH S ATMOSPHERE SO BOTH REFLECTION NEBULAE AND EARTH S ATMOSPHERE APPEAR BLUE.
3 M16 -- Star Birth in the Nest of the Eagle Stars are born from the gas of interstellar space. When they eventually burnout and die, they bequeath their legacy back to the interstellar medium from which they formed. The signposts marking this ongoing cycle of birth, death, and renewal would be easily visible to any casual observer who had a bird's-eye view of our pinwheel-shaped galaxy. Spread across our galaxy such an observer would see majestic spiral arms, highlighted by bright young stars and the glowing clouds of gas that those stars illuminate. On a clear, dark summer night earth-based observers can see these glowing clouds, called nebulae, scattered along the track of the Milky Way. Many can be found by looking in the direction of the great star clouds in the summer constellation, Sagittarius. One of the most unique star-birth regions is the Eagle Nebula, (also called M16 because it is in the Messier Catalog of "fuzzy" permanent objects in the sky, that was compiled more than 200 years ago by French astronomer Charles Messier) it is visible in binoculars near the border between the constellations of Sagittarius and Serpens. The nebula is actually a bowl-shaped blister on the side of a dense cloud of cold interstellar gas. Most of this cloud is so dense and cool that its hydrogen atoms are bound as molecules. This "molecular hydrogen" is the raw material for building new stars. The cloud contains microscopic dust particles of carbon (in the form of graphite), silicates and other compounds similar to those found in terrestrial and lunar rocks. Though this trace dust accounts for only a fraction of the nebula's mass, it's enough dust to absorb visible light -- cloaking some of the visual details of star birth. A cluster of about 100 newborn stars glitters inside the open "bowl" of the nebula. A few of these stars are much more massive than our Sun is, and so are tremendously hotter and brighter than the Sun. The brightest of these stars may be 100,000 times brighter than the Sun and have temperatures of nearly 90,000 degrees Fahrenheit (50,000 degrees Kelvin). These young stars emit intense ultraviolet radiation which is so energetic it heats the surrounding gas, causing it to glow like the gas inside a fluorescent light bulb. When this ultraviolet light hits the bowl-shaped surface of the molecular cloud, it heats that gas, causing it to "evaporate" and stream away from the surface. If one could watch the process for more than a million years, they would see the bowl grow increasingly larger as the radiation from the stars eats deeper into the molecular cloud. Unlike other stellar nebula which we see face-on -- like the great Orion Nebula -- M16 presents astronomers with a unique side view of the structure of a typical star-birth region: the cluster of hot, young stars in the center of the cavity, the evaporating surface of the cloud, and finally the great cold mass of the cloud itself. The Eagle Nebula's name comes from its symmetrical appearance which is reminiscent of a bird of prey with outstretched wings and talons bared. The Eagle's "talons" are actually a series of dense columns of gas that protrude into the interior of the nebula. These columns form as a result of the same process that causes the bowl to grow. Because the columns are denser than their surroundings, they are not evaporating as rapidly as the surrounding gas, and so remain. The process is analogous to the formation of towering buttes and spires in the deserts of the American Southwest. These geological features formed when wind and rain eroded away softer ground, but places where the rock was harder resisted erosion and were left behind. Inside these interstellar columns, the gas density can get so high that gravity takes over and causes the gas to start collapsing into ever-smaller clumps. As more and more gas falls onto these growing clumps they get further compressed by their own weight, until finally they trigger nuclear fusion reactions in their cores, and "turn on" as stars. However, in M16 this process may not get a chance to go on to completion. If a forming star and the gas cloud that surrounds it are "uncovered" by photoevaporation before the star finishes growing, the mass of the young star may be "frozen." The star can't grow any more simply because the cloud from which it was drawing material is gone. In M16 Hubble Space Telescope's high resolution seems to have caught about 50 stars in this situation. These are called EGGs "evaporating gaseous globules." The acronym is appropriate because these EGGs are objects within which stars are being born and are now emerging. M16 is where the action is today, but it won't remain so forever. Within another few million years, star formation will have exhausted or dispersed the available raw material, and the massive stars that illuminate the Eagle will have lived out their short lives and died in spectacular supernova explosions. But even though the "birth cloud" nebula will be gone, most of the stars that formed there will remain. The offspring of the Eagle will "take wing" among the rest of the hundreds of billions of stars that make up our galaxy.
4 Giant Molecular Clouds: Breeding Grounds for Star Birth Space between stars in a galaxy is nearly empty, except for a scattering of hydrogen atoms. The atoms are so far apart that, if an atom were an average- size person, each person would be separated by about 465 million miles, which is the distance between our Sun and Jupiter. These atoms are moving very fast because they are extremely hot, baked by ultraviolet radiation from stars. This makes it difficult for atoms to bond to form molecules. Those that do form don't last for long. If radiation doesn't break these molecules apart, a chance encounter with another atom will. Some parts of space, however, are not wide open frontiers containing a few atoms. These cosmic spaces comprise dense clouds of dust and gas left over from galaxy formation. Since these clouds are cooler than most places, they are perfect breeding grounds for star birth. When the density is 1,000 times greater than what is found in normal interstellar space, many atoms combine into molecules, and the gas cloud becomes a molecular cloud. Like clouds in our sky, these molecular clouds are puffy and lumpy. Molecular clouds in our Milky Way Galaxy have diameters ranging from less than 1 light-year to about 300 light-years and contain enough gas to form from about 10 to 10 million stars like our Sun. Molecular clouds that exceed the mass of 100,000 suns are called Giant Molecular Clouds. A typical full-grown spiral galaxy contains about 1,000 to 2,000 Giant Molecular Clouds and many more smaller ones. Such clouds were first discovered in our Milky Way Galaxy with radio telescopes about 25 years ago. Since the molecules in these clouds do not emit optical light, but do release light at radio wavelengths, radio telescopes are necessary to trace the molecular gas and study its physical properties. Most of this gas is very cold (about -440 degrees Fahrenheit) because it's shielded from ultraviolet light. Since gas is more compact in a colder climate, it is easier for gravity to collapse it to form new stars. Ironically, the same climate that is conducive to star formation also may shut off the star birth process. The problem is heat. Young stars are very hot and can heat the molecular gas to more than 1,000 degrees Fahrenheit, which is an unfavorable climate for star birth. When the temperature exceeds about 3,000 degrees Fahrenheit, the gas molecules break down into atoms. The density of the gas can increase considerably near the centers of some Giant Molecular Clouds: Gas as dense as 1 billion molecules per cubic inch has been observed. (Though dense by astronomical standards, such gas is still 100 billion times thinner than the air we breathe here on Earth at sea level!) In such dense regions, still denser blobs of gas can condense and create new stars. Although the star formation process is not fully understood, there is observational evidence that most stars are born in the densest parts of molecular clouds. What happens when stars begin forming in Giant Molecular Clouds depends on the environment. Under normal conditions in the Milky Way and in most other present-day spiral galaxies, star birth will stop after a relatively small number of stars have been born. That's because the stellar nursery is blown away by some of the newly formed stars. The hottest of these heat the surrounding molecular gas, break up its molecules, and drive the gas away. As the celestial smog of gas and dust clears, the previously hidden young stars become visible, and the molecular cloud and its star-birthing capability cease to exist. Two years ago the Hubble Space Telescope revealed such an emerging stellar nursery in the three gaseous pillars of the Eagle Nebula. Giant Molecular Clouds in colliding galaxies may experience a different fate. As the collision crunches the interstellar gas and stars form at an accelerating rate, the gas pressure around the surviving Giant Molecular Clouds increases one-hundred- to one-thousand-fold. Calculations suggest that the hot surrounding gas can trigger rapid star birth throughout the clouds by driving shock waves into them. The several hundred thousand stars that form from the cold molecular gas in such clouds use up most of the gas before it has time to be heated and dispersed. The result of such violent events is the nearly complete conversion of Giant Molecular Clouds into rich star clusters, each containing up to 1 million stars. Observations by the Hubble telescope suggest that many of these newly born star clusters remain bound by their own gravity and evolve into globular clusters, like those observed in the halo of our Milky Way.
5 Nebular Questions (hah!...it s funny trust me) Astronomy Name: Period: Use the articles provided and the any additional sources necessary to answer the following questions: From Giant Molecular Clouds article: 1. Is all the space in galaxies totally empty? NEARLY EMPTY EXCEPT FOR A SCATTERING OF HYDROGEN ATOMS 2. If so how can gaseous clouds form. If not, what s the difference between the clouds and the rest of space? CLOUDS ARE LEFT OVER FROM GALAXY FORMATION 3. How do space clouds compare to that of clouds on earth? MOLECULAR CLOUDS ARE PUFFY AND LUMPY LIKE ATMOSPHERIC CLOUDS 4. How large are Giant Molecular Clouds? BETWEEN LESS THAN 1 LIGHT YEAR ACROSS AND 300 LIGHT YEARS ACROSS 5. How many are in a galaxy? TO 2, How are they detected? Explain! MOLECULES DO NOT EMIT OPTICAL LIGHT BUT DO EMIT RADIO WAVES, SO THEY ARE DETECTED BY RADIO TELESCOPES IN PLACES WHERE THEY CANNOT BE DETECTED BY OPTICAL TELESCOPES 7. Explain why cold temperatures are good for star birth and why hot temperatures are bad for star birth. COLD TEMPERATURES ALLOW FOR DENSITIES GREAT ENOUGH FOR MOLECULES TO FORM, HOT TEMPERATURES BREAK THE MOLECULES INTO ATOMS MAKING IT MORE POSSIBLE FOR THEM TO EVAPORATE 8. How much more dense is a giant molecular cloud than our air? 100 BILLION TIMES THINNER THAN OUR ATMOSPHERE 9. Why does star birth in galaxies like the Milky way stop after small numbers of stars have been born? THE INTERSTELLAR MEDIUM IS BLOWN AWAY BY THE NEW STARS 10. According to the Antennae galaxy website, what is another trigger for star formation? COLLIDING GALAXIES 11. Explain why this happens? THE COLLISION OF GALAXIES CAUSES THEIR INTERSTELLAR MEDIUM TO CRUNCH AND FORM NEW STARS.
6 From M16 article 12. What causes the columns of the Eagle Nebula? THE COLUMNS ARE DENSER REGIONS OF THE NEBULA THAT HAVE BEEN MORE RESISTANT TO THE EVAPORATION OF THE SURROUNDING GAS. 13. In what constellation is the Eagle Nebula? (RA 18:18, Dec. 13O 47 ) BETWEEN SAGITTARIUS AND SERPENS 14. What are EGG s? (include what EGG stands for and what s happening there) EVAPORATING GASEUS GLOBULES A FROZEN PROTO STAR THAT CANNOT DRAW MORE GAS IN TO GROW BECAUSE THE GASSES HAVE EVAPORATED 15. Look at the illuminated portion of the Eagle Nebula image. How many EGGs can you count on that pillar? FROM P IDENTIFIED BY AUTHOR, AND APPROXIMATELY 8 MORE. 16. Look at the eagle nebula image to see EGG s on stalks that stick out from pillars. Draw a sketch, labeling the pillar, and EGG. 17. What will stop star formation in the Eagle Nebula? THE NEBULA WILL EXHAUST OR DISPERSETHE AVAILABLE RAW MATERIAL. 18. What is the main element in gas clouds? HYDROGEN 19. What is evaporating the gas around the EGG s? ULTRAVIOLET RADIATION FROM A NEARBY STAR HEATS THE GASSES 20. Why aren t the EGG s evaporating as fast? GRAVITY OF THE DENSE DUST COUNTERACTS THE EVAPORATION EFFECT
7 Chapter 11 The Formation of Stars Notes/Homework Astronomy Name: Period: Use pages to answer the following questions Making Stars from the Interstellar Medium 1. What is the key to star formation? THERE IS A CORELLATION BETWEEN YOUNG STARS AND CLOUDS OF GAS 2. A typical Giant Molecular Cloud: a. has a diameter of 50 PC b. has a mass of 10 5 SOLAR MASSSES c. has a density of TIMES LESS DENSE THAN A STAR d. has a temperature of A FEW DEGRESS KELVIN 3. There are four factors that gravity must overcome in order to begin star formation. Briefly describe each. a. The thermal energy of Hydrogen. CAUSES MOTION OF ATOMS AND MOLECULES, DISPERSING THEM b. Interstellar magnetic field IONIZED GASSES CANNOT MOVE FREELY THROUGH A MAGNETIC FIELD c. rotation RAPID ROTATION RESISTS FURTHER CONTRACTION OF THE CLOUD d. Turbulence of the interstellar medium CURRENTS THROUGH THE MEDIUM MAKES IT DIFFICULT FOR A CLOUD TO CONTRACT 4. Explain the role that shock waves are believed to play in the formation of stars. COMPRESSES A CLOUD, CREATING AREAS THAT ARE VERY DENSE AND START TO COLLAPSE GRAVITATIONALLY 5. List the four possible causes of shock waves. SUPERNOVA EXPLOSIONS, IGNITION OF HOT STARS IONIZES GAS WHICH CREATES A SHOCK WAVE WHEN IT IS PUSHED INTO COLDER, DENSER INTERSTELLAR MATTER COLLISION OF MOLECULAR CLOUDS SPIRAL PATTERN OF SOME GALAXIES SPIRAL ARMS MAY BE SHOCK WAVES 6. Explain free fall contraction and how it contributes to the formation of stars. ATOMS FALL TOWARDS THE CENTER OF THE GRAVITATIONAL MASS, COLLIDE WITH EACH OTHER AND PRODUCE THERMAL ENERGY 7. An important principle in astronomy. Whenever a cloud of gas CONTRACTS, gravitational energy is converted into thermal energy and the gas grows HOT. Whenever a cloud of gas ROTATES, thermal energy is converted into gravitational energy and the gas ACCRETES (OR CONTRACTS MORE_). 8. What is a protostar? How long is it s life (see page 218)? Draw a simple sketch of it and it s cocoon. THE LIFE OF THE PROTOSTAR DEPENDS ON ITS MASS BETWEEN 100 MILLION YEARS FOR A LOW MASS STAR, TO 0.16 MILLION YEARS FOR A HIGH MASS STAR.
8 9. What is a protostellar disk and what are they responsible for? FLATTENED DISK OF GAS AND DUST SURROUNDING A PROTOSTAR, THESE ARE RESPONSIBLE FOR THE FORMATION OF PLANETS. 10. When the protostar becomes HOT enough, it can drive away surrounding GAS and DUST and become VISIBLE. 11. What is the birth line and how does it relate to the main sequence? THE LINE ON THE H-R DIAGRAM THAT IS APPROXIMATELY PARALLEL AND TO THE RIGHT OF THE MAIN SEQUENCE LINE WHERE PROTOSTARS FIRST APPEAR WHEN THEY BECOME VISIBLE. 12. Using the two pages after 219, give at least four pieces of evidence of star formation. LOW MASS STARS IN CLUSTER NGC2264 WHICH ARE NEAR THE BIRTH LINE T TAURI STARS ARE IRREGULAR IN BRIGHNESS SUGGESTING THEY ARE SURROUNDED BY DUST AND GAS BRIGHT HOT STARS HAVE A SHORT LIFE EXPECTANCY SO THEY MUST HAVE BEEN FROMED RECENTLY HERBIG-HARO OBJECTS SMALL NEBULAE THAT FLUCTUATE IN BRIGHTNESS AND PRODUCE FLICKERING JETS THAT EXCITE INTERSTELLAR MEDIUM EVIDENCE OF STAR FORMATION BECAUSE ONLY DISCS COULD PRODUCE A JET EAGLE NEBULA PHOTOS SHOW EVAPORATING DUST DRIVING AWAY THE GAS TO EXPOSE GLOBULES 11-2: The Source of Stellar Energy 13. How is the CNO cycle different from the proton-proton chain version of fusion? VERY SIMILAR BUT USES A CARBON ATOM AS CATALYST AND IS VERY TEMERATURE SENSITIVE. AT LOWER TEMPERATURES CNO CYCLE RELEASES VERY LITTLE ENERGY BUT AT HIGHER TEMPERATURES RELEASES MUCH MORE ENERGY. 11-3: Stellar Structure 14. Stars can exist only as long as energy can move from their CORE to their SURFACE. 15. Summarize the three methods of energy flow THEN explain how it applies to stars. a. Convection HOT REGIONS OF GAS RISE TO THE SURFACE WHERE THE GAS IS COOLED AND SINKS. IN STARS THIS CARRIES ENERGY TO THE SURFACE AND MIXES THE GASSES.
9 b. Conduction TRANSFER OF HEAT ENERGY BY CONTACT AND ONLY IMPORTANT IN STARS WITH VERY HIGH INTERNAL DENSITIES. c. Radiation HEAT ENERGY FROM THE CORE IS RADIATED OUT TO THE ATMOSPHERE. THIS HEATS A STARS PHOTOSPHERE WHICH RELEASES LIGHT ENERGY AS A RESULT. 16. The sun is balanced between two forces GRAVITY trying to squeeze it tighter and PRESSURE trying to make it expand. 17. Upper main sequence stars fuse Hydrogen on the CNO cycle, and lower main sequence stars fuse hydrogen on the PROTON-PROTON chain. Reading Questions from page 229. RQ 3. A - MANY STARS ARE FORMED FROM CLOUDS OF GAS EJECTED BY A SUPERNOVA EXPLOSION EVIDENCE THAT STAR FORMATION IS SOMETIMES CYCLICAL B BOK GLOBULES, T TAURI STARS AND HERBIG HARO OBJECTS ARE EVIDENCE THAT PROTOSTARS EXIST C- ORION NEBULA HAS T TAURI STARS, AND SUPER HOT STARS THAT MUST BE VERY YOUNG (BECAUSE THEY HAVE A SHORT LIFE EXPECTANCY) DQ 1 (p. 232) ANCIENT ASTRONOMERS LIKELY OBSERVED SUPERNOVAE, IF THEY OBSERVED A SUPERNOVA OF A CHARTED STAR, THEN THEY WOULD HAVE KNOWN THAT STARS CAN UNDERGO TREMENDOUS CHANGES IN LUMINOSITY AND THEN DISAPPEAR.
Topics for Today s Class
Foundations of Astronomy 13e Seeds Chapter 11 Formation of Stars and Structure of Stars Topics for Today s Class 1. Making Stars from the Interstellar Medium 2. Evidence of Star Formation: The Orion Nebula
More informationChapter 11 The Formation of Stars
Chapter 11 The Formation of Stars A World of Dust The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful objects in the sky.
More informationChapter 9. The Formation and Structure of Stars
Chapter 9 The Formation and Structure of Stars The Interstellar Medium (ISM) The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful
More informationChapter 11 The Formation and Structure of Stars
Chapter 11 The Formation and Structure of Stars Guidepost The last chapter introduced you to the gas and dust between the stars that are raw material for new stars. Here you will begin putting together
More informationThe Interstellar Medium. Papillon Nebula. Neutral Hydrogen Clouds. Interstellar Gas. The remaining 1% exists as interstellar grains or
The Interstellar Medium About 99% of the material between the stars is in the form of a gas The remaining 1% exists as interstellar grains or interstellar dust If all the interstellar gas were spread evenly,
More informationStellar evolution Part I of III Star formation
Stellar evolution Part I of III Star formation The interstellar medium (ISM) The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful
More informationClicker Question: Clicker Question: What is the expected lifetime for a G2 star (one just like our Sun)?
How Long do Stars Live (as Main Sequence Stars)? A star on Main Sequence has fusion of H to He in its core. How fast depends on mass of H available and rate of fusion. Mass of H in core depends on mass
More informationChapter 16 Lecture. The Cosmic Perspective Seventh Edition. Star Birth Pearson Education, Inc.
Chapter 16 Lecture The Cosmic Perspective Seventh Edition Star Birth 2014 Pearson Education, Inc. Star Birth The dust and gas between the star in our galaxy is referred to as the Interstellar medium (ISM).
More informationPhysics Homework Set 2 Sp 2015
1) A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as 1) A) a reflection nebula. B) a dark patch against a bright background. C) a dark nebula.
More information18. Stellar Birth. Initiation of Star Formation. The Orion Nebula: A Close-Up View. Interstellar Gas & Dust in Our Galaxy
18. Stellar Birth Star observations & theories aid understanding Interstellar gas & dust in our galaxy Protostars form in cold, dark nebulae Protostars evolve into main-sequence stars Protostars both gain
More informationGuiding Questions. The Birth of Stars
Guiding Questions The Birth of Stars 1 1. Why do astronomers think that stars evolve (bad use of term this is about the birth, life and death of stars and that is NOT evolution)? 2. What kind of matter
More informationStar Formation. Stellar Birth
Star Formation Lecture 12 Stellar Birth Since stars don t live forever, then they must be born somewhere and at some time in the past. How does this happen? And when stars are born, so are planets! 1 Molecular
More informationAtoms and Star Formation
Atoms and Star Formation What are the characteristics of an atom? Atoms have a nucleus of protons and neutrons about which electrons orbit. neutrons protons electrons 0 charge +1 charge 1 charge 1.67 x
More informationThe Ecology of Stars
The Ecology of Stars We have been considering stars as individuals; what they are doing and what will happen to them Now we want to look at their surroundings And their births 1 Interstellar Matter Space
More informationEnergy. mosquito lands on your arm = 1 erg. Firecracker = 5 x 10 9 ergs. 1 stick of dynamite = 2 x ergs. 1 ton of TNT = 4 x ergs
Energy mosquito lands on your arm = 1 erg Firecracker = 5 x 10 9 ergs 1 stick of dynamite = 2 x 10 13 ergs 1 ton of TNT = 4 x 10 16 ergs 1 atomic bomb = 1 x 10 21 ergs Magnitude 8 earthquake = 1 x 10 26
More informationThe Formation of Stars
The Formation of Stars A World of Dust The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful objects in the sky. We are interested
More informationSTAR FORMATION (Ch. 19)
STAR FORMATION (Ch. 19) The basics: GRAVITY vs. PRESSURE (heat; but also rotation and magnetic fields can be important) Stages (you don t have to memorize numbers of stages in textbook or here, just be
More informationStellar Birth. Stellar Formation. A. Interstellar Clouds. 1b. What is the stuff. Astrophysics: Stellar Evolution. A. Interstellar Clouds (Nebulae)
Astrophysics: Stellar Evolution 1 Stellar Birth Stellar Formation A. Interstellar Clouds (Nebulae) B. Protostellar Clouds 2 C. Protostars Dr. Bill Pezzaglia Updated: 10/02/2006 A. Interstellar Clouds 1.
More informationChapter 16 Lecture. The Cosmic Perspective Seventh Edition. Star Birth Pearson Education, Inc.
Chapter 16 Lecture The Cosmic Perspective Seventh Edition Star Birth Star Birth 16.1 Stellar Nurseries Our goals for learning: Where do stars form? Why do stars form? Where do stars form? Star-Forming
More informationChapter 16: Star Birth
Chapter 16 Lecture Chapter 16: Star Birth Star Birth 16.1 Stellar Nurseries Our goals for learning: Where do stars form? Why do stars form? Where do stars form? Star-Forming Clouds Stars form in dark clouds
More informationThe Birth Of Stars. How do stars form from the interstellar medium Where does star formation take place How do we induce star formation
Goals: The Birth Of Stars How do stars form from the interstellar medium Where does star formation take place How do we induce star formation Interstellar Medium Gas and dust between stars is the interstellar
More informationStar-Forming Clouds. Stars form in dark clouds of dusty gas in interstellar space. The gas between the stars is called the interstellar medium.
Star Birth Chapter 16 Lecture 16.1 Stellar Nurseries The Cosmic Perspective Our goals for learning: Where do stars form? Why do stars form? Seventh Edition Star Birth Where do stars form? Star-Forming
More informationAstro 1050 Wed. Apr. 5, 2017
Astro 1050 Wed. Apr. 5, 2017 Today: Ch. 17, Star Stuff Reading in Horizons: For Mon.: Finish Ch. 17 Star Stuff Reminders: Rooftop Nighttime Observing Mon, Tues, Wed. 1 Ch.9: Interstellar Medium Since stars
More informationGuiding Questions. Stellar Evolution. Stars Evolve. Interstellar Medium and Nebulae
Guiding Questions Stellar Evolution 1. Why do astronomers think that stars evolve? 2. What kind of matter exists in the spaces between the stars? 3. What steps are involved in forming a star like the Sun?
More informationAstronomy 1 Fall 2016
Astronomy 1 Fall 2016 Lecture11; November 1, 2016 Previously on Astro-1 Introduction to stars Measuring distances Inverse square law: luminosity vs brightness Colors and spectral types, the H-R diagram
More informationStellar Astronomy Sample Questions for Exam 4
Stellar Astronomy Sample Questions for Exam 4 Chapter 15 1. Emission nebulas emit light because a) they absorb high energy radiation (mostly UV) from nearby bright hot stars and re-emit it in visible wavelengths.
More informationChapter 12: The Lives of Stars. How do we know it s there? Three Kinds of Nebulae 11/7/11. 1) Emission Nebulae 2) Reflection Nebulae 3) Dark Nebulae
11/7/11 Chapter 12: The Lives of Stars Space is Not Empty The Constellation Orion The Orion Nebula This material between the stars is called the Interstellar Medium It is very diffuse and thin. In fact
More informationThe Night Sky. The Universe. The Celestial Sphere. Stars. Chapter 14
The Night Sky The Universe Chapter 14 Homework: All the multiple choice questions in Applying the Concepts and Group A questions in Parallel Exercises. Celestial observation dates to ancient civilizations
More informationRecall what you know about the Big Bang.
What is this? Recall what you know about the Big Bang. Most of the normal matter in the universe is made of what elements? Where do we find most of this normal matter? Interstellar medium (ISM) The universe
More information8/30/2010. Classifying Stars. Classifying Stars. Classifying Stars
Classifying Stars In the early 1900s, Ejnar Hertzsprung and Henry Russell made some important observations. They noticed that, in general, stars with higher temperatures also have brighter absolute magnitudes.
More information10/29/2009. The Lives And Deaths of Stars. My Office Hours: Tuesday 3:30 PM - 4:30 PM 206 Keen Building. Stellar Evolution
of s Like s of Other Stellar The Lives And Deaths of s a Sun-like s More 10/29/2009 My Office Hours: Tuesday 3:30 PM - 4:30 PM 206 Keen Building Test 2: 11/05/2009 of s Like s of Other a Sun-like s More
More informationLecture 21 Formation of Stars November 15, 2017
Lecture 21 Formation of Stars November 15, 2017 1 2 Birth of Stars Stars originally condense out of a COLD, interstellar cloud composed of H and He + trace elements. cloud breaks into clumps (gravity)
More informationPrentice Hall EARTH SCIENCE
Prentice Hall EARTH SCIENCE Tarbuck Lutgens Chapter 25 Beyond Our Solar System 25.1 Properties of Stars Characteristics of Stars A constellation is an apparent group of stars originally named for mythical
More information25.2 Stellar Evolution. By studying stars of different ages, astronomers have been able to piece together the evolution of a star.
25.2 Stellar Evolution By studying stars of different ages, astronomers have been able to piece together the evolution of a star. Star Birth The birthplaces of stars are dark, cool interstellar clouds,
More informationThe Interstellar Medium (ch. 18)
The Interstellar Medium (ch. 18) The interstellar medium (ISM) is all the gas (and about 1% dust) that fills our Galaxy and others. It is the raw material from which stars form, and into which stars eject
More informationBeyond Our Solar System Chapter 24
Beyond Our Solar System Chapter 24 PROPERTIES OF STARS Distance Measuring a star's distance can be very difficult Stellar parallax Used for measuring distance to a star Apparent shift in a star's position
More informationChapter 11 Review. 1) Light from distant stars that must pass through dust arrives bluer than when it left its star. 1)
Chapter 11 Review TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 1) Light from distant stars that must pass through dust arrives bluer than when it left its star. 1)
More informationCosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE
Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE Cosmology Cosmology is the study of the universe; its nature, origin and evolution. General Relativity is the mathematical basis of cosmology from which
More informationUniverse Now. 9. Interstellar matter and star clusters
Universe Now 9. Interstellar matter and star clusters About interstellar matter Interstellar space is not completely empty: gas (atoms + molecules) and small dust particles. Over 10% of the mass of the
More informationTAKE A LOOK 2. Identify This star is in the last stage of its life cycle. What is that stage?
CHAPTER 15 2 SECTION Stars, Galaxies, and the Universe The Life Cycle of Stars BEFORE YOU READ After you read this section, you should be able to answer these questions: How do stars change over time?
More information25/11/ Cosmological Red Shift:
12.1 Edwin Hubble Discovered galaxies other than the milky way. Galaxy: A collection of stars, planets, gas, and dust that are held together by gravity. Our sun and planets are in the Milky Way Hubble
More informationName Date Period. 10. convection zone 11. radiation zone 12. core
240 points CHAPTER 29 STARS SECTION 29.1 The Sun (40 points this page) In your textbook, read about the properties of the Sun and the Sun s atmosphere. Use each of the terms below just once to complete
More informationLife Cycle of a Star - Activities
Name: Class Period: Life Cycle of a Star - Activities A STAR IS BORN STAGES COMMON TO ALL STARS All stars start as a nebula. A nebula is a large cloud of gas and dust. Gravity can pull some of the gas
More informationStars and Galaxies 1
Stars and Galaxies 1 Characteristics of Stars 2 Star - body of gases that gives off great amounts of radiant energy as light and heat 3 Most stars look white but are actually different colors Antares -
More informationAstronomy 10 Test #2 Practice Version
Given (a.k.a. `First ) Name(s): Family (a.k.a. `Last ) name: ON YOUR PARSCORE: `Bubble your name, your student I.D. number, and your multiple-choice answers. I will keep the Parscore forms. ON THIS TEST
More informationAstr 2310 Thurs. March 23, 2017 Today s Topics
Astr 2310 Thurs. March 23, 2017 Today s Topics Chapter 16: The Interstellar Medium and Star Formation Interstellar Dust and Dark Nebulae Interstellar Dust Dark Nebulae Interstellar Reddening Interstellar
More information5) What spectral type of star that is still around formed longest ago? 5) A) F B) A C) M D) K E) O
HW2 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The polarization of light passing though the dust grains shows that: 1) A) the dust grains
More informationChapter Introduction Lesson 1 The View from Earth Lesson 2 The Sun and Other Stars Lesson 3 Evolution of Stars Lesson 4 Galaxies and the Universe
Chapter Introduction Lesson 1 The View from Earth Lesson 2 The Sun and Other Stars Lesson 3 Evolution of Stars Lesson 4 Galaxies and the Universe Chapter Wrap-Up What makes up the universe and how does
More informationStars & Galaxies. Chapter 27, Section 1. Composition & Temperature. Chapter 27 Modern Earth Science Characteristics of Stars
Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars Composition & Temperature Scientists use the following tools to study stars Telescope Observation Spectral
More informationAST 101 Introduction to Astronomy: Stars & Galaxies
AST 101 Introduction to Astronomy: Stars & Galaxies The H-R Diagram review So far: Stars on Main Sequence (MS) Next: - Pre MS (Star Birth) - Post MS: Giants, Super Giants, White dwarfs Star Birth We start
More informationStars & Galaxies. Chapter 27 Modern Earth Science
Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars How do astronomers determine the composition and surface temperature of a star? Composition & Temperature
More informationChapter 33 The History of a Star. Introduction. Radio telescopes allow us to look into the center of the galaxy. The milky way
Chapter 33 The History of a Star Introduction Did you read chapter 33 before coming to class? A. Yes B. No You can see about 10,000 stars with the naked eye. The milky way Radio telescopes allow us to
More informationBeyond the Solar System 2006 Oct 17 Page 1 of 5
I. Stars have color, brightness, mass, temperature and size. II. Distances to stars are measured using stellar parallax a. The further away, the less offset b. Parallax angles are extremely small c. Measured
More informationChapter 10 The Interstellar Medium
Chapter 10 The Interstellar Medium Guidepost You have begun your study of the sun and other stars, but now it is time to study the thin gas and dust that drifts through space between the stars. This chapter
More informationAstronomy 1504 Section 002 Astronomy 1514 Section 10 Midterm 2, Version 1 October 19, 2012
Astronomy 1504 Section 002 Astronomy 1514 Section 10 Midterm 2, Version 1 October 19, 2012 Choose the answer that best completes the question. Read each problem carefully and read through all the answers.
More information1 The Life Cycle of a Star
CHAPTER 1 The Life Cycle of a Star Describe the life cycle of various size stars. Rings of glowing gas encircling Supernova 1987A, about 179,000 light-years away in the Large Magellanic Cloud, one of the
More informationStellar Life Cycle in Giant Galactic Nebula NGC 3603
Stellar Life Cycle in Giant Galactic Nebula NGC 3603 edited by David L. Alles Western Washington University e-mail: alles@biol.wwu.edu Last Updated 2009-11-20 Note: In PDF format most of the images in
More information10/26/ Star Birth. Chapter 13: Star Stuff. How do stars form? Star-Forming Clouds. Mass of a Star-Forming Cloud. Gravity Versus Pressure
10/26/16 Lecture Outline 13.1 Star Birth Chapter 13: Star Stuff How do stars form? Our goals for learning: How do stars form? How massive are newborn stars? Star-Forming Clouds Stars form in dark clouds
More informationEdwin Hubble Discovered galaxies other than the milky way. Galaxy:
Edwin Hubble Discovered galaxies other than the milky way. Galaxy: A collection of stars, planets, gas, and dust that are held together by gravity. Our sun and planets are in the Milky Way He noticed that
More informationWhere do Stars Form?
Where do Stars Form? Coldest spots in the galaxy: T ~ 10 K Composition: Mainly molecular hydrogen 1% dust EGGs = Evaporating Gaseous Globules ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1995/95-190.txt Slide
More informationEarth Science, 13e Tarbuck & Lutgens
Earth Science, 13e Tarbuck & Lutgens Beyond Our Solar System Earth Science, 13e Chapter 24 Stanley C. Hatfield Southwestern Illinois College Properties of stars Distance Distances to the stars are very
More informationExplain how the sun converts matter into energy in its core. Describe the three layers of the sun s atmosphere.
Chapter 29 and 30 Explain how the sun converts matter into energy in its core. Describe the three layers of the sun s atmosphere. Explain how sunspots are related to powerful magnetic fields on the sun.
More informationThe Milky Way Galaxy and Interstellar Medium
The Milky Way Galaxy and Interstellar Medium Shape of the Milky Way Uniform distribution of stars in a band across the sky lead Thomas Wright, Immanuel Kant, and William Herschel in the 18th century to
More informationPossible Extra Credit Option
Possible Extra Credit Option Attend an advanced seminar on Astrophysics or Astronomy held by the Physics and Astronomy department. There are seminars held every 2:00 pm, Thursday, Room 190, Physics & Astronomy
More informationAstronomy 104: Second Exam
Astronomy 104: Second Exam Stephen Lepp October 29, 2014 Each question is worth 2 points. Write your name on this exam and on the scantron. Short Answer A The Sun is powered by converting hydrogen to what?
More informationStars, Galaxies & the Universe Lecture Outline
Stars, Galaxies & the Universe Lecture Outline A galaxy is a collection of 100 billion stars! Our Milky Way Galaxy (1)Components - HII regions, Dust Nebulae, Atomic Gas (2) Shape & Size (3) Rotation of
More informationA World of Dust. Bare-Eye Nebula: Orion. Interstellar Medium
Interstellar Medium Physics 113 Goderya Chapter(s): 10 Learning Outcomes: A World of Dust The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of
More informationProperties of Stars. Characteristics of Stars
Properties of Stars Characteristics of Stars A constellation is an apparent group of stars originally named for mythical characters. The sky contains 88 constellations. Star Color and Temperature Color
More informationCHAPTER 29: STARS BELL RINGER:
CHAPTER 29: STARS BELL RINGER: Where does the energy of the Sun come from? Compare the size of the Sun to the size of Earth. 1 CHAPTER 29.1: THE SUN What are the properties of the Sun? What are the layers
More informationNumber of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc)
THE MILKY WAY GALAXY Type: Spiral galaxy composed of a highly flattened disk and a central elliptical bulge. The disk is about 100,000 light years (30kpc) in diameter. The term spiral arises from the external
More informationThe Universe. But first, let s talk about light! 2012 Pearson Education, Inc.
The Universe But first, let s talk about light! Light is fast! The study of light All forms of radiation travel at 300,000,000 meters (186,000 miles) per second Since objects in space are so far away,
More informationThe Universe and Galaxies
The Universe and Galaxies 16.1 http://dingo.care-mail.com/cards/flash/5409/galaxy.swf Universe The sum of all matter and energy that exists, that has ever existed, and that will ever exist. We will focus
More informationThe Birth and Death of Stars
The Birth and Death of Stars 2013 Simulation Curriculum Teachers may make copies for their classes Part 1: Stellar Cradles With a small telescope the central region of M42 reveals a group of at least four
More informationTEACHER BACKGROUND INFORMATION
TEACHER BACKGROUND INFORMATION (The Universe) A. THE UNIVERSE: The universe encompasses all matter in existence. According to the Big Bang Theory, the universe was formed 10-20 billion years ago from a
More informationA Star is born: The Sun. SNC1D7-Space
A Star is born: The Sun SNC1D7-Space Exploring the Sun Our Sun, a star, is the most important celestial object for life on Earth. The solar nebula theory is the current theory used to explain the formation
More informationAstronomy Stars, Galaxies and Cosmology Exam 3. Please PRINT full name
Astronomy 132 - Stars, Galaxies and Cosmology Exam 3 Please PRINT full name Also, please sign the honor code: I have neither given nor have I received help on this exam The following exam is intended to
More informationA protostar forming in the Orion Nebula. This also has protoplanetary discs, and will probably become a planetary system.
A protostar forming in the Orion Nebula. This also has protoplanetary discs, and will probably become a planetary system. These are also called stellar nurseries. Consisting almost entirely of hydrogen,
More information1. What is the primary difference between the evolution of a low-mass star and that of a high-mass star?
FYI: The Lives of Stars E3:R6b 1. Read FYI: The Lives of Stars As you read use the spaces below to write down any information you find especially interesting. Also define the bold terms used in the text.
More informationStellar Evolution: Outline
Stellar Evolution: Outline Interstellar Medium (dust) Hydrogen and Helium Small amounts of Carbon Dioxide (makes it easier to detect) Massive amounts of material between 100,000 and 10,000,000 solar masses
More informationTHE INTERSTELLAR MEDIUM
THE INTERSTELLAR MEDIUM An IR view of dust clouds In particular, light from polycyclic aromatic hydrocarbons (PAH s) Little bit of carbon out there, forms hydrocarbons like car exhaust Associated with
More informationCh. 25 In-Class Notes: Beyond Our Solar System
Ch. 25 In-Class Notes: Beyond Our Solar System ES2a. The solar system is located in an outer edge of the disc-shaped Milky Way galaxy, which spans 100,000 light years. ES2b. Galaxies are made of billions
More informationANSWER KEY. Stars, Galaxies, and the Universe. Telescopes Guided Reading and Study. Characteristics of Stars Guided Reading and Study
Stars, Galaxies, a the Universe Stars, Galaxies, and the Universe Telescopes Use Target Reading Skills Check student definitions for accuracy. 1. Electromagneticradiationisenergythatcan travel through
More informationStars and their properties: (Chapters 11 and 12)
Stars and their properties: (Chapters 11 and 12) To classify stars we determine the following properties for stars: 1. Distance : Needed to determine how much energy stars produce and radiate away by using
More informationCST Prep- 8 th Grade Astronomy
CST Prep- 8 th Grade Astronomy Chapter 15 (Part 1) 1. The theory of how the universe was created is called the 2. Which equation states that matter and energy are interchangeable? 3. All matter in the
More informationStellar Evolution. Stars are chemical factories The Earth and all life on the Earth are made of elements forged in stars
Lecture 11 Stellar Evolution Stars are chemical factories The Earth and all life on the Earth are made of elements forged in stars A Spiral Galaxy (Milky Way Type) 120,000 ly A few hundred billion stars
More informationBased on the reduction of the intensity of the light from a star with distance. It drops off with the inverse square of the distance.
6/28 Based on the reduction of the intensity of the light from a star with distance. It drops off with the inverse square of the distance. Intensity is power per unit area of electromagnetic radiation.
More informationThe History of the Solar System. From cloud to Sun, planets, and smaller bodies
The History of the Solar System From cloud to Sun, planets, and smaller bodies The Birth of a Star Twenty years ago, we knew of only one star with planets the Sun and our understanding of the birth of
More informationGalaxies Galore. Types of Galaxies: Star Clusters. Spiral spinning wit arms Elliptical roundish Irregular no set pattern
Stars Studying Stars Astronomers use a spectroscope to study the movement of stars Blue shift towards earth Red shift away from earth Change in a wavelength moving toward or away from earth is the Doppler
More informationChapter 15 Star Birth. Star-Forming Clouds. Stars form in dark clouds of dusty gas in interstellar space
Chapter 15 Star Birth Star-Forming Clouds Stars form in dark clouds of dusty gas in interstellar space The gas between the stars is called the interstellar medium Visible light (Hubble Space Telescope)
More informationThe physics of stars. A star begins simply as a roughly spherical ball of (mostly) hydrogen gas, responding only to gravity and it s own pressure.
Lecture 4 Stars The physics of stars A star begins simply as a roughly spherical ball of (mostly) hydrogen gas, responding only to gravity and it s own pressure. X-ray ultraviolet infrared radio To understand
More informationChapter 14. Stellar Evolution I. The exact sequence of evolutionary stages also depends on the mass of a star.
Chapter 14 Stellar Evolution I I. Introduction Stars evolve in the sense that they pass through different stages of a stellar life cycle that is measured in billions of years. The longer the amount of
More informationReview Questions for the new topics that will be on the Final Exam
Review Questions for the new topics that will be on the Final Exam Be sure to review the lecture-tutorials and the material we covered on the first three exams. How does speed differ from velocity? Give
More informationUNIT 3: Astronomy Chapter 26: Stars and Galaxies (pages )
CORNELL NOTES Directions: You must create a minimum of 5 questions in this column per page (average). Use these to study your notes and prepare for tests and quizzes. Notes will be turned in to your teacher
More informationLIFE CYCLE OF A STAR
LIFE CYCLE OF A STAR First stage = Protostar PROTOSTAR Cloud of gas and dust many light-years across Gravity tries to pull the materials together Eventually, at the center of the ball of dust and gas,
More informationStellar Evolution Notes
Name: Block: Stellar Evolution Notes Stars mature, grow old and die. The more massive a star is, the shorter its life will be. Our Sun will live about 10 billion years. It is already 5 billion years old,
More informationNSCI 314 LIFE IN THE COSMOS
NSCI 314 LIFE IN THE COSMOS 2 BASIC ASTRONOMY, AND STARS AND THEIR EVOLUTION Dr. Karen Kolehmainen Department of Physics CSUSB COURSE WEBPAGE: http://physics.csusb.edu/~karen MOTIONS IN THE SOLAR SYSTEM
More informationAstro Fall 2012 Lecture 8. T. Howard
Astro 101 003 Fall 2012 Lecture 8 T. Howard Measuring the Stars How big are stars? How far away? How luminous? How hot? How old & how much longer to live? Chemical composition? How are they moving? Are
More informationOur goals for learning: 2014 Pearson Education, Inc. We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters All-Sky View
Our Galaxy Chapter 19 Lecture The Cosmic Perspective 19.1 The Milky Way Revealed What does our galaxy look like? What does our galaxy look like? How do stars orbit in our galaxy? Seventh Edition Our Galaxy
More informationread 9.4-end 9.8(HW#6), 9.9(HW#7), 9.11(HW#8) We are proceding to Chap 10 stellar old age
HW PREVIEW read 9.4-end Questions 9.9(HW#4), 9(HW#4) 9.14(HW#5), 9.8(HW#6), 9.9(HW#7), 9.11(HW#8) We are proceding to Chap 10 stellar old age Chap 11 The death of high h mass stars Contraction of Giant
More informationThe Life and Death of Stars
The Life and Death of Stars A Star Is Born Not everyone agrees, but it is generally thought that stars originate from nebulae (clouds of dust and gas). Almost inevitably, a nebula will "collapse" into
More information