Physics- HSC- Module 9.7 Astrophysics
... brightest stars; stars in a young open cluster; stars in a globular cluster 2. (Act 13) analyse information from a H-R diagram and use available evidence to determine the characteristics of a star and its evolutionary ...
... brightest stars; stars in a young open cluster; stars in a globular cluster 2. (Act 13) analyse information from a H-R diagram and use available evidence to determine the characteristics of a star and its evolutionary ...
Gravitational redshifts
... synthetic line profiles) are shorter than laboratory values due to convective blueshift. Curves before and after mid-transit (µ = 0.21, 0.59, 0.87) are not exact mirror images due to intrinsic stellar line asymmetries. This simulation from a CO5BOLD model predicts the behavior of an Fe I line ( 620 ...
... synthetic line profiles) are shorter than laboratory values due to convective blueshift. Curves before and after mid-transit (µ = 0.21, 0.59, 0.87) are not exact mirror images due to intrinsic stellar line asymmetries. This simulation from a CO5BOLD model predicts the behavior of an Fe I line ( 620 ...
55-80 BIOGRAPHY_of_A STAR
... enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion (triple alpha) starts very sharply Hint: this is a strong reaction (no neutrinos) once the temperature is hot enough to overcome ...
... enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion (triple alpha) starts very sharply Hint: this is a strong reaction (no neutrinos) once the temperature is hot enough to overcome ...
Stars A globular cluster is a tightly grouped swarm of stars held
... light-years. The sun is in a galaxy called the Milky Way that contains more than 100 billion stars. There are more than 100 billion galaxies in the universe, and the average number of stars per galaxy may be 100 billion. Thus, more than 10 billion trillion stars may exist. But if you look at the nig ...
... light-years. The sun is in a galaxy called the Milky Way that contains more than 100 billion stars. There are more than 100 billion galaxies in the universe, and the average number of stars per galaxy may be 100 billion. Thus, more than 10 billion trillion stars may exist. But if you look at the nig ...
Transcript - Chandra X
... diagram is a plot of absolute magnitude (and/or luminosity) and temperature (and/or stellar classification) and where a star is plotted shows its evolutionary stage. Stars with stable hydrogen fusion in the core are located on the main sequence – and they evolve to other branches of the diagram when ...
... diagram is a plot of absolute magnitude (and/or luminosity) and temperature (and/or stellar classification) and where a star is plotted shows its evolutionary stage. Stars with stable hydrogen fusion in the core are located on the main sequence – and they evolve to other branches of the diagram when ...
Life Stages of High
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses ...
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses ...
Powerpoint - Physics and Astronomy
... a) its mass exceeds the Chandrasekhar limit. b) its electron degeneracy increases enormously. c) fusion reactions increase in it’s core. d) iron in its core collapses. e) the planetary nebula stage ends. Explanation: If additional mass from a a companion star pushes a white dwarf beyond 1.4 solar ma ...
... a) its mass exceeds the Chandrasekhar limit. b) its electron degeneracy increases enormously. c) fusion reactions increase in it’s core. d) iron in its core collapses. e) the planetary nebula stage ends. Explanation: If additional mass from a a companion star pushes a white dwarf beyond 1.4 solar ma ...
Measuring Distances
... Measuring Distances Hold your finger out in front of your face at arm’s length. Look at your finger through each eye separately. What do you notice? This change in perspective is known as parallax. Ancient Greek astronomers expected to see a similar change in the positions of nearby stars if Earth ...
... Measuring Distances Hold your finger out in front of your face at arm’s length. Look at your finger through each eye separately. What do you notice? This change in perspective is known as parallax. Ancient Greek astronomers expected to see a similar change in the positions of nearby stars if Earth ...
Chapter 20
... helium flash before the star is once again in equilibrium. © 2011 Pearson Education, Inc. ...
... helium flash before the star is once again in equilibrium. © 2011 Pearson Education, Inc. ...
Stellar Evolution – Cosmic Cycles of Formation and Destruction
... becomes depleted and the fusion of hydrogen nuclei to helium nuclei stops. The massluminosity relationship for main sequence stars is defined as: L/L (Sun) ~ [M/M (Sun)]4. All main sequence stars with a mass less than ~8 solar masses are sometimes referred to as dwarf stars, with the coolest, least ...
... becomes depleted and the fusion of hydrogen nuclei to helium nuclei stops. The massluminosity relationship for main sequence stars is defined as: L/L (Sun) ~ [M/M (Sun)]4. All main sequence stars with a mass less than ~8 solar masses are sometimes referred to as dwarf stars, with the coolest, least ...
Ch12&13 Life and Death of Stars
... • X is fusing in the core, making Y, but the core eventually runs out of X. • Core contracts, allowing layers around the core to heat up, initiating an X-burning shell around the core. • The shell burning does nothing for the core, but does change the star’s overall radius. • Core continues to contr ...
... • X is fusing in the core, making Y, but the core eventually runs out of X. • Core contracts, allowing layers around the core to heat up, initiating an X-burning shell around the core. • The shell burning does nothing for the core, but does change the star’s overall radius. • Core continues to contr ...
lect3 — 1 Measuring stars: What can be measured?
... H-R diagram distance: We discussed the H-R diagram last time as a relation between temperature and luminosity. In observational terms, it is actually a color-magnitude diagram; color corresponds to temperature, while magnitude corresponds to luminosity. For a main sequence star, M can be estimated b ...
... H-R diagram distance: We discussed the H-R diagram last time as a relation between temperature and luminosity. In observational terms, it is actually a color-magnitude diagram; color corresponds to temperature, while magnitude corresponds to luminosity. For a main sequence star, M can be estimated b ...
The Life Cycle of A Star
... dwarfs are stable because the inward pull of gravity is balanced by the electrons in the core of the star repulsing each other. With no fuel left to burn, the hot star radiates its remaining heat into the coldness of space for many billions of years. In the end, it will just sit in space as a cold d ...
... dwarfs are stable because the inward pull of gravity is balanced by the electrons in the core of the star repulsing each other. With no fuel left to burn, the hot star radiates its remaining heat into the coldness of space for many billions of years. In the end, it will just sit in space as a cold d ...
Lesson 3 - The Life Cycle of Stars - Hitchcock
... How are stars plotted on the H-R diagram? • Astronomers refer to brightness as luminosity. Luminosity is a measure of the total amount of energy a star gives off each second. • When the surface temperatures of stars are plotted against their luminosity, a consistent pattern is revealed. • The graph ...
... How are stars plotted on the H-R diagram? • Astronomers refer to brightness as luminosity. Luminosity is a measure of the total amount of energy a star gives off each second. • When the surface temperatures of stars are plotted against their luminosity, a consistent pattern is revealed. • The graph ...
– 1 – 1. Historical Notes for Ay 123 1.1.
... Self gravitating sphere (or almost sphere) of gas with a finite definable radius, not easily deformed, not like a cloud in the Earth’s atmosphere Nuclear reactions occur at least to the point where 3 He is produced. radiates energy into the surrounding medium. Jupiter also does this, some internal h ...
... Self gravitating sphere (or almost sphere) of gas with a finite definable radius, not easily deformed, not like a cloud in the Earth’s atmosphere Nuclear reactions occur at least to the point where 3 He is produced. radiates energy into the surrounding medium. Jupiter also does this, some internal h ...
The Helium Flash • When the temperature of a stellar core reaches T
... • During helium core burning, the radius of the helium core will remain approximately constant. The core will not contract until the helium fraction reaches Y < 0.1. Once it does, the star will restructure itself in a manner similar to that of the hydrogenexhaustion phase. First, the stellar core w ...
... • During helium core burning, the radius of the helium core will remain approximately constant. The core will not contract until the helium fraction reaches Y < 0.1. Once it does, the star will restructure itself in a manner similar to that of the hydrogenexhaustion phase. First, the stellar core w ...
The Stars education kit - Student activities 5-10
... contract. This expansion cools the star, causing it to glow red in colour. Helium in the contracting core begins to fuse to form carbon and oxygen. This new cycle of nuclear reactions halts the collapse of the core. Variable Star Some stars then become variable stars. The brightness of these stars v ...
... contract. This expansion cools the star, causing it to glow red in colour. Helium in the contracting core begins to fuse to form carbon and oxygen. This new cycle of nuclear reactions halts the collapse of the core. Variable Star Some stars then become variable stars. The brightness of these stars v ...
Star
A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.