Lecture 13 Hydrogen Burning on the Main Sequence and Homology
... A more detailed calculation gives 0.08 solar masses. Protostars lighter than this can never ignite nuclear reactions. They are known as brown dwarfs (or planets if the mass is less than 13 Jupiter masses, or about 0.01 solar masses. [above 13 Jupiter masses, some minor nuclear reactions occur that d ...
... A more detailed calculation gives 0.08 solar masses. Protostars lighter than this can never ignite nuclear reactions. They are known as brown dwarfs (or planets if the mass is less than 13 Jupiter masses, or about 0.01 solar masses. [above 13 Jupiter masses, some minor nuclear reactions occur that d ...
ISM and star formation
... Star Formation Stars form out of molecular gas clouds. Clouds must collapse to form stars (remember, stars are ~1020 x denser than a molecular cloud). Do molecular clouds collapse or are they stable (like a star)? Depends on balance of pressure and gravity. Gravity makes cloud want to collapse. ...
... Star Formation Stars form out of molecular gas clouds. Clouds must collapse to form stars (remember, stars are ~1020 x denser than a molecular cloud). Do molecular clouds collapse or are they stable (like a star)? Depends on balance of pressure and gravity. Gravity makes cloud want to collapse. ...
Life and Death of a Star
... – The Stellar Cloud collapses so much that the internal temperature and pressure rise dramatically – The Core begins to push back against Gravity and the Protostar is formed – The core is NOT yet hot enough for Fusion – However the seed of a new star is planted ...
... – The Stellar Cloud collapses so much that the internal temperature and pressure rise dramatically – The Core begins to push back against Gravity and the Protostar is formed – The core is NOT yet hot enough for Fusion – However the seed of a new star is planted ...
Section 27.2
... stable part of their life cycle. White dwarfs are hot and dim and cannot be seen without a telescope. Red giants are cool and bright and some can be seen without a telescope. Can you locate blue giants on the H-R diagram? ...
... stable part of their life cycle. White dwarfs are hot and dim and cannot be seen without a telescope. Red giants are cool and bright and some can be seen without a telescope. Can you locate blue giants on the H-R diagram? ...
Lec6
... cores are no longer on the main sequence • All stars become larger and redder after exhausting their core hydrogen: giants and ...
... cores are no longer on the main sequence • All stars become larger and redder after exhausting their core hydrogen: giants and ...
Homework Problems for Quiz 1 – AY 5 – Spring 2013
... 11. Star A has twice the trigonometric parallax angle and twice the luminosity of Star B. (Assume no dust toward either star) a) What are the relative distances of the two stars? Star A has twice the parallax angle so is at 1/2 the distance of Star B b) what are the relative brightnesses of the two ...
... 11. Star A has twice the trigonometric parallax angle and twice the luminosity of Star B. (Assume no dust toward either star) a) What are the relative distances of the two stars? Star A has twice the parallax angle so is at 1/2 the distance of Star B b) what are the relative brightnesses of the two ...
Die Sonne im Röntgenlicht - ST-ECF
... HST/NICMOS P Emission Survey of the Galactic Center: 1.90 m Map 15’ (115 light-year) ...
... HST/NICMOS P Emission Survey of the Galactic Center: 1.90 m Map 15’ (115 light-year) ...
friends of the planetarium newsletter
... has beamed back close-up photographs of asteroid Lutetia, an ancient, cratered relic from the dawn of the solar system. Scientists are abuzz about the stunning images, which reveal a worldlet of haunting, alien beauty. Asteroid Lutetia has been a target of interest among astronomers for many years. ...
... has beamed back close-up photographs of asteroid Lutetia, an ancient, cratered relic from the dawn of the solar system. Scientists are abuzz about the stunning images, which reveal a worldlet of haunting, alien beauty. Asteroid Lutetia has been a target of interest among astronomers for many years. ...
Lecture10
... not too hot and not too cold, many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
... not too hot and not too cold, many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
Lecture7
... Photodisintegration: By this time the central temperature is so high that heavy nuclei hit by high energy photons (gamama rays) disintegrate to He nuclei ( particles)- so, photodisintegration. Core Collapse: Fusion of light elements up to Fe releases nuclear energy. However, the reverse, from Fe to ...
... Photodisintegration: By this time the central temperature is so high that heavy nuclei hit by high energy photons (gamama rays) disintegrate to He nuclei ( particles)- so, photodisintegration. Core Collapse: Fusion of light elements up to Fe releases nuclear energy. However, the reverse, from Fe to ...
Life Cycle of a Star - Intervention Worksheet
... The stages below are not in the right order. Number the stages in the correct order. _____ The star begins to run out of fuel and expands into a red giant or red super giant. _____ Stars start out as diffused clouds of gas and dust drifting through space. A single one of these clouds is called a neb ...
... The stages below are not in the right order. Number the stages in the correct order. _____ The star begins to run out of fuel and expands into a red giant or red super giant. _____ Stars start out as diffused clouds of gas and dust drifting through space. A single one of these clouds is called a neb ...
Sun and Stars
... nuclear fusion in its core. This nuclear fusion releases energy which travels through the star's different layers and then radiates into outer space. ...
... nuclear fusion in its core. This nuclear fusion releases energy which travels through the star's different layers and then radiates into outer space. ...
Astro 1 & 100 Levine Homework Stars Name:____________________________
... Hottest ______ ______ ______ ______ ______ ______ Coolest Or, all have the same temperature ______________ Page 1 ! of !4 ...
... Hottest ______ ______ ______ ______ ______ ______ Coolest Or, all have the same temperature ______________ Page 1 ! of !4 ...
chapter-30-pp
... slightly toward blue. This is called a “blue shift”. This is caused by shorter light waves as it moves toward Earth. ...
... slightly toward blue. This is called a “blue shift”. This is caused by shorter light waves as it moves toward Earth. ...
Habitibility of Earth, in our Solar System, and Beyond
... restricted habitable zones, and more variable planetary environments. Imagine our solar system with a small star in place of Jupiter! ...
... restricted habitable zones, and more variable planetary environments. Imagine our solar system with a small star in place of Jupiter! ...
Chapter 28 – Stars and Galaxies
... outer layers will get blown away and only an earth-sized fiery hot carbon-oxygen core ...
... outer layers will get blown away and only an earth-sized fiery hot carbon-oxygen core ...
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.