Powerpoint of lecture 14
... central temperature gradient steeper in more massive stars • Steep gradient unstable to convection → convective core (radiative core in less massive stars with pp chain) • Less massive stars have cooler surfaces => ionisation zones in surface regions → convective envelopes (more massive stars ionise ...
... central temperature gradient steeper in more massive stars • Steep gradient unstable to convection → convective core (radiative core in less massive stars with pp chain) • Less massive stars have cooler surfaces => ionisation zones in surface regions → convective envelopes (more massive stars ionise ...
Make one copy for each student on plain paper. Life Cycle of Star
... A huge cloud of gas and dust that begins to shrink under the pull of its own gravity. This stellar nebula is the beginning of all star’s lives. ...
... A huge cloud of gas and dust that begins to shrink under the pull of its own gravity. This stellar nebula is the beginning of all star’s lives. ...
Life Cycle of Star Pictures
... A huge cloud of gas and dust that begins to shrink under the pull of its own gravity. This stellar nebula is the beginning of all star’s lives. ...
... A huge cloud of gas and dust that begins to shrink under the pull of its own gravity. This stellar nebula is the beginning of all star’s lives. ...
22_SN1987a
... The Supernova Explosion • The core collapses until the neutrons touch: The collapse stops because of neutron degeneracy pressure • A shock wave rebounds through the outer layers of the star: some of the neutrons fly out through the ejecta and make heavy elements by 56Fe + Nn 56+NX • The core cont ...
... The Supernova Explosion • The core collapses until the neutrons touch: The collapse stops because of neutron degeneracy pressure • A shock wave rebounds through the outer layers of the star: some of the neutrons fly out through the ejecta and make heavy elements by 56Fe + Nn 56+NX • The core cont ...
Properties of stars during hydrogen burning
... The star will settle into a hydrostatic and thermal equilibrium, where cooling is balanced by nuclear energy generation and there is no time dependence of any state variables. The generated heat will then exactly match the outgoing energy flow (luminosity) at any point in the star. Heat flows from h ...
... The star will settle into a hydrostatic and thermal equilibrium, where cooling is balanced by nuclear energy generation and there is no time dependence of any state variables. The generated heat will then exactly match the outgoing energy flow (luminosity) at any point in the star. Heat flows from h ...
Degeneracy pressure Normal/degeneracy pressure White dwarfs — Oct 10
... from SN, now by blast wave from SN. ...
... from SN, now by blast wave from SN. ...
Gold could have come from colliding stars - Horizon Magazine
... ‘The formation of heavy elements is a major topic in stellar astrophysics,’ said Dr Bauswein. ‘We want to understand where and how elements like gold and uranium were produced.’ Our own fairly small star, the sun, can generate helium by fusing pairs of atoms of the lightest element, hydrogen, at tem ...
... ‘The formation of heavy elements is a major topic in stellar astrophysics,’ said Dr Bauswein. ‘We want to understand where and how elements like gold and uranium were produced.’ Our own fairly small star, the sun, can generate helium by fusing pairs of atoms of the lightest element, hydrogen, at tem ...
AST101 Lecture 20 The Ecology of the Galaxy
... • About 1010 years old • 105 - 106 stars • Radius ~ 10 light years • Most massive star: ~ 1 solar mass • ~150 globular clusters known in Milky Way ...
... • About 1010 years old • 105 - 106 stars • Radius ~ 10 light years • Most massive star: ~ 1 solar mass • ~150 globular clusters known in Milky Way ...
Groups_of_Stars_spectra
... • Emission spectra: Produced from a heated gas giving off light • Absorption spectra: Produced when white light passes through a cool gas ...
... • Emission spectra: Produced from a heated gas giving off light • Absorption spectra: Produced when white light passes through a cool gas ...
Study Guide- Tools of Astronomy
... 11. A. List AND Explain the steps of stellar evolution. B. List the type of fuel associated with each step. C. List the sequence of evolution for high and low mass stars. 12. List, in order, the steps of hydrogen fusion. ...
... 11. A. List AND Explain the steps of stellar evolution. B. List the type of fuel associated with each step. C. List the sequence of evolution for high and low mass stars. 12. List, in order, the steps of hydrogen fusion. ...
Binary Star Par 1802 Word Document
... which throws up questions. It consists of two young stars which have not yet reached the main sequence (i.e. they haven’t settled down into a stable hydrogen-burning state) and each have about 40% of the Sun’s mass. They apparently formed together about 1 million years ago. Their radii are approxima ...
... which throws up questions. It consists of two young stars which have not yet reached the main sequence (i.e. they haven’t settled down into a stable hydrogen-burning state) and each have about 40% of the Sun’s mass. They apparently formed together about 1 million years ago. Their radii are approxima ...
word document - FacStaff Home Page for CBU
... _____ e) The sun will probably go supernova sometime, probably in about 5.5 billion years. _____ f) Vega is a star that has a stellar classification of A0 V. From this we can infer that Vega is more massive than the sun. _____ g) The heaviest elements (gold, lead, uranium, etc.) are thought to be ma ...
... _____ e) The sun will probably go supernova sometime, probably in about 5.5 billion years. _____ f) Vega is a star that has a stellar classification of A0 V. From this we can infer that Vega is more massive than the sun. _____ g) The heaviest elements (gold, lead, uranium, etc.) are thought to be ma ...
Life Cycles of Stars
... The Heavens Are Not Changeless • The Stars Move – Most of our constellations would have been unrecognizable to Neanderthal Man ...
... The Heavens Are Not Changeless • The Stars Move – Most of our constellations would have been unrecognizable to Neanderthal Man ...
Energy Generation in Stars
... 1017 seconds which is about 10 billion years. Thus for a star like the sun, it will take about 10 billion years for the core hydrogen to be fully converted to Helium. We are about 1/2 way through that process now. Overall the evolutionary timescale of main sequence stars is entirely driven by stella ...
... 1017 seconds which is about 10 billion years. Thus for a star like the sun, it will take about 10 billion years for the core hydrogen to be fully converted to Helium. We are about 1/2 way through that process now. Overall the evolutionary timescale of main sequence stars is entirely driven by stella ...
8.1 Stars
... Low mass stars use their nuclear fuel much more slowly than more massive stars do. Low mass stars burn so slowly that they can last for 100 billion year. This is due to less gravity and thus less pressure. The light from a red dwarf starts dim and gradually grows dimmer. Eventually they collapse ...
... Low mass stars use their nuclear fuel much more slowly than more massive stars do. Low mass stars burn so slowly that they can last for 100 billion year. This is due to less gravity and thus less pressure. The light from a red dwarf starts dim and gradually grows dimmer. Eventually they collapse ...
Question: Fossilized footprints of Coelophysis
... Picking the right table: The key word fossil suggests the Geologic History of New York State table (pp. NY26–NY27). You can use this table to look up the geologic era in which Coelophysis lived. The Generalized Bedrock Geology of New York State (p. NY21) contains a key with geological eras, as well ...
... Picking the right table: The key word fossil suggests the Geologic History of New York State table (pp. NY26–NY27). You can use this table to look up the geologic era in which Coelophysis lived. The Generalized Bedrock Geology of New York State (p. NY21) contains a key with geological eras, as well ...
Measuring the Stars
... Spectroscopic parallax: Has nothing to do with parallax, but does use spectroscopy in finding the distance to a star. 1. Measure the star’s apparent magnitude and ...
... Spectroscopic parallax: Has nothing to do with parallax, but does use spectroscopy in finding the distance to a star. 1. Measure the star’s apparent magnitude and ...
name - New York Science Teacher
... 10. -What spectral class of stars is the hottest? ____________________________ 11. -What spectral class of stars is the coolest? ____________________________ 12. - What spectral class is our sun? ____________________________ ...
... 10. -What spectral class of stars is the hottest? ____________________________ 11. -What spectral class of stars is the coolest? ____________________________ 12. - What spectral class is our sun? ____________________________ ...
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.