RFS_315_answers
... mass of a star the shorter it’s lifetime as it’s fuel is used much faster. Algol B is a dying K giant star but at only .81 solar masses, it is the LESS massive of the two. The dim companion has lost a great deal of mass to it’s closely orbiting partner. 15. Polaris is a variable star – what type of ...
... mass of a star the shorter it’s lifetime as it’s fuel is used much faster. Algol B is a dying K giant star but at only .81 solar masses, it is the LESS massive of the two. The dim companion has lost a great deal of mass to it’s closely orbiting partner. 15. Polaris is a variable star – what type of ...
Star Formation: Interstellar Gas and Dust
... long as main seq. life. • Helium flash (34He Î12C) • He shell burning. • C Î heavier elements. ...
... long as main seq. life. • Helium flash (34He Î12C) • He shell burning. • C Î heavier elements. ...
Lecture 5/10 The interstellar medium and star formation Ulf
... τ = 2/3, at which the radiation is emitted, will move inwards. Since the emitting surface decreases the temperature must increase in order for the luminosity to remain high. At 2000 K the molecular hydrogen dissociates, which costs energy and the core starts to collapse again. Equilibrium will be re ...
... τ = 2/3, at which the radiation is emitted, will move inwards. Since the emitting surface decreases the temperature must increase in order for the luminosity to remain high. At 2000 K the molecular hydrogen dissociates, which costs energy and the core starts to collapse again. Equilibrium will be re ...
White Dwarfs - Indiana University
... Upper mass limit for white dwarf formation is somewhere between 5-9 solar masses – “Inside every red giant is a white dwarf waiting to get out” (Warner) Most have C-O cores, most massive may have O-Ne cores In hot, pre-white dwarfs, neutrinos dominate energy loss When nuclear burning stops, photon c ...
... Upper mass limit for white dwarf formation is somewhere between 5-9 solar masses – “Inside every red giant is a white dwarf waiting to get out” (Warner) Most have C-O cores, most massive may have O-Ne cores In hot, pre-white dwarfs, neutrinos dominate energy loss When nuclear burning stops, photon c ...
Star Formation
... and spend most of their lives • Once on the main sequence, a star stays in the same location on the H-R diagram until it runs out of fuel and begins to die ...
... and spend most of their lives • Once on the main sequence, a star stays in the same location on the H-R diagram until it runs out of fuel and begins to die ...
Homework 4
... Due November 2, 2012 at 5 p.m., either electronically or on paper. 1. If a protostar is forming out of a cold molecular cloud, how can its luminosity be upto one hundred times as large as the luminosity of the star it will become? ...
... Due November 2, 2012 at 5 p.m., either electronically or on paper. 1. If a protostar is forming out of a cold molecular cloud, how can its luminosity be upto one hundred times as large as the luminosity of the star it will become? ...
Free Referat Word Dimensiune: 63.5KB
... When the helium is exhausted in the core of a star like the sun, the C-O core will begin to contract again. Central temperatures will never reach high enough values for Carbon or Oxygen burning, but the Helium and Hydrogen burning shells will conyinue burning for a while. Throughout the star's lifet ...
... When the helium is exhausted in the core of a star like the sun, the C-O core will begin to contract again. Central temperatures will never reach high enough values for Carbon or Oxygen burning, but the Helium and Hydrogen burning shells will conyinue burning for a while. Throughout the star's lifet ...
AST 207 Test 2 Answers 20 October 2010
... star A. Prof. Adams says he discovered a new type of star that is fainter than white dwarfs. Has he discovered a new type of star? Explain. The clues are very much like Walter Adams’ discovery that Sirius B is a white dwarf. However, there is a crucial missing clue. Since Sirius A and B were known t ...
... star A. Prof. Adams says he discovered a new type of star that is fainter than white dwarfs. Has he discovered a new type of star? Explain. The clues are very much like Walter Adams’ discovery that Sirius B is a white dwarf. However, there is a crucial missing clue. Since Sirius A and B were known t ...
Stellar Evolution - University of California, Santa Cruz
... • Lower mass limit for stars is 0.08 solar masses -this is the mass below which the central temperature is <10 million K • Upper mass limit is around 100 solar masses set by inability for a star to hang on to its outer layers because high radiation pressure (high luminosity). ...
... • Lower mass limit for stars is 0.08 solar masses -this is the mass below which the central temperature is <10 million K • Upper mass limit is around 100 solar masses set by inability for a star to hang on to its outer layers because high radiation pressure (high luminosity). ...
The Stellar Graveyard
... loss during the various phases of stellar evolution following hydrogen core exhaustion. Measuring the current mass of a white dwarf, therefore, does not indicate what its initial mass was. A 0.5 solar mass white dwarf could have easily started out life as a 10 solar mass main sequence star. A white ...
... loss during the various phases of stellar evolution following hydrogen core exhaustion. Measuring the current mass of a white dwarf, therefore, does not indicate what its initial mass was. A 0.5 solar mass white dwarf could have easily started out life as a 10 solar mass main sequence star. A white ...
Lecture19
... is 3.72 MeV. Given 0.075 MSun of this isotope (this is how much was estimated to have been produced in SN1987A) how much energy does the decay release? ...
... is 3.72 MeV. Given 0.075 MSun of this isotope (this is how much was estimated to have been produced in SN1987A) how much energy does the decay release? ...
The Origin of the Elements - Indiana University Astronomy
... After helium exhausted, a small star is not large enough to reach temperatures necessary to fuse carbon to heavier elements ...
... After helium exhausted, a small star is not large enough to reach temperatures necessary to fuse carbon to heavier elements ...
Stars and Galaxies PP 2013
... High mass supergiants may undergo a supernova, where the core suddenly collapses and explodes. A neutron star is what remains after the supernova. It is composed mainly of neutrons and is very dense. If it spins and releases radiation it is called a pulsar. ...
... High mass supergiants may undergo a supernova, where the core suddenly collapses and explodes. A neutron star is what remains after the supernova. It is composed mainly of neutrons and is very dense. If it spins and releases radiation it is called a pulsar. ...
galaxy
... The most distant galaxies ever photographed are as far as 10 billion to 13 billion light-years away. Large galaxies have more than a trillion stars. Only three galaxies outside the Milky Way are visible with the unaided eye. People in the Northern Hemisphere can see the Andromeda Galaxy, which is ab ...
... The most distant galaxies ever photographed are as far as 10 billion to 13 billion light-years away. Large galaxies have more than a trillion stars. Only three galaxies outside the Milky Way are visible with the unaided eye. People in the Northern Hemisphere can see the Andromeda Galaxy, which is ab ...
Deaths of Stars - Chabot College
... Degenerate matter obeys different laws of physics. More massive star => smaller core becomes! ...
... Degenerate matter obeys different laws of physics. More massive star => smaller core becomes! ...
Document
... • Stars don’t live forever. Stars expand as it grows old. After the hydrogen (fuel) is used up, the star will begin to die. The core contracts and the outer layers expand, cool, and become less bright. It then becomes a red giant star. • Helium is now being used, and the core begins to shrink, and o ...
... • Stars don’t live forever. Stars expand as it grows old. After the hydrogen (fuel) is used up, the star will begin to die. The core contracts and the outer layers expand, cool, and become less bright. It then becomes a red giant star. • Helium is now being used, and the core begins to shrink, and o ...
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.