Spectropolarimetric view of the lower atmosphere of
... II - Sciences et techniques, IN2P3 – Université de Montpellier II Place Eugène Bataillon - CC 72 34095 Montpellier Cédex 05, France ...
... II - Sciences et techniques, IN2P3 – Université de Montpellier II Place Eugène Bataillon - CC 72 34095 Montpellier Cédex 05, France ...
Microsoft Word - LifeCycleInteractive
... 21. Why does the outer shell of the star expand? 22. As the outer shell of the star expands, the surface temperature of the star decreases. Helium burning is much hotter than hydrogen burning. Why would the surface temperature decrease? Close quiz window. 23. The red giant is the first step in _____ ...
... 21. Why does the outer shell of the star expand? 22. As the outer shell of the star expands, the surface temperature of the star decreases. Helium burning is much hotter than hydrogen burning. Why would the surface temperature decrease? Close quiz window. 23. The red giant is the first step in _____ ...
Groupmeeting_shshiu_20090803_nuclearx
... The rapid proton capture process consists of consecutive proton captures onto nuclei to produce heavier elements. The possible sites suggested for the rp-process are binary systems. One star is a compact object, the other one is low mass black hole or neutron star. The rp-process is constrained by a ...
... The rapid proton capture process consists of consecutive proton captures onto nuclei to produce heavier elements. The possible sites suggested for the rp-process are binary systems. One star is a compact object, the other one is low mass black hole or neutron star. The rp-process is constrained by a ...
Our Universe
... • Protostar: • A baby star - formed in the nebulas after the gases have condensed enough to begin nuclear fusion • In Nuclear fusion, hydrogen atoms are converted into helium, releasing the ENORMOUS amount of energy that causes stars to become very hot! • The amount of energy released per gram of ma ...
... • Protostar: • A baby star - formed in the nebulas after the gases have condensed enough to begin nuclear fusion • In Nuclear fusion, hydrogen atoms are converted into helium, releasing the ENORMOUS amount of energy that causes stars to become very hot! • The amount of energy released per gram of ma ...
The Origin of the Elements edited by David L. Alles Western Washington University
... The fuel which supplies the heat is hydrogen. Hydrogen nuclei are converted to helium as heat is released. Five billion years from now the Sun's hydrogen fuel will be depleted. Gravity will then force the spent core, now almost pure helium, to shrink, compress, and become even hotter than at present ...
... The fuel which supplies the heat is hydrogen. Hydrogen nuclei are converted to helium as heat is released. Five billion years from now the Sun's hydrogen fuel will be depleted. Gravity will then force the spent core, now almost pure helium, to shrink, compress, and become even hotter than at present ...
The Milky Way – A Classic Galaxy
... bright open cluster M23 has a Cepheid. As of 1999, 29 more clusters now known to have Cepheids. • Cepheid PL relation has much less noise if brightnesses measured in the Infrared, which is what is always done these days. • By “Cepheids” I mean “Classical Cepheids”. There are also “Type II Cepheids” ...
... bright open cluster M23 has a Cepheid. As of 1999, 29 more clusters now known to have Cepheids. • Cepheid PL relation has much less noise if brightnesses measured in the Infrared, which is what is always done these days. • By “Cepheids” I mean “Classical Cepheids”. There are also “Type II Cepheids” ...
Lecture 3 - QUB Astrophysics Research Centre
... potential of H. Thus the gas must be highly ionised, i.e. is a plasma. It can thus withstand greater compression without deviating from an ideal gas. Note that an ideal gas demands that the distances between the particles are much greater than their sizes, and nuclear dimension is 10-15 m compared t ...
... potential of H. Thus the gas must be highly ionised, i.e. is a plasma. It can thus withstand greater compression without deviating from an ideal gas. Note that an ideal gas demands that the distances between the particles are much greater than their sizes, and nuclear dimension is 10-15 m compared t ...
PHY-105: Equations of Stellar Structure
... also a function or r) – see previous handout for more discussion of opacity. These 4 equations have 7 unknowns (at a given r): P , Mr , Lr , T , ρ, ǫ, κ. So in general we require expressions for P , κ, and ǫ in terms of ρ, T , and the compositions. These can be complicated, but for example if we ass ...
... also a function or r) – see previous handout for more discussion of opacity. These 4 equations have 7 unknowns (at a given r): P , Mr , Lr , T , ρ, ǫ, κ. So in general we require expressions for P , κ, and ǫ in terms of ρ, T , and the compositions. These can be complicated, but for example if we ass ...
Chapter 24
... • Energy is released • Outward pressure increases • Outward pressure balanced by gravity pulling in • Star becomes a stable main-sequence star ...
... • Energy is released • Outward pressure increases • Outward pressure balanced by gravity pulling in • Star becomes a stable main-sequence star ...
Stellar Lives (continued). Galaxies.
... Intermediate-mass stars blow their outer layers away and become white dwarfs. ...
... Intermediate-mass stars blow their outer layers away and become white dwarfs. ...
Test - Hampton Science 8A 8B 8C 8D 8E Stars are classified on the
... Stars are classified on the Hertzsprung - Russell diagram according to their absolute magnitude and their surface temperatures at a given time in a star’s life cycle. What classification would a star have if it was very hot and very bright? ...
... Stars are classified on the Hertzsprung - Russell diagram according to their absolute magnitude and their surface temperatures at a given time in a star’s life cycle. What classification would a star have if it was very hot and very bright? ...
9 - WordPress.com
... present information by plotting Hertzsprung-Russell diagrams for: nearby or brightest stars, stars in a young open cluster, stars in a globular cluster ...
... present information by plotting Hertzsprung-Russell diagrams for: nearby or brightest stars, stars in a young open cluster, stars in a globular cluster ...
Lecture 10: The Hertzsprung
... sample of stars where we get all the stars within a certain distance of the Sun to figure out how many stars of what masses are out there. Answer: Lots of low-mass stars! Very few high-mass stars. This is something our theory of star formation will need to explain. ...
... sample of stars where we get all the stars within a certain distance of the Sun to figure out how many stars of what masses are out there. Answer: Lots of low-mass stars! Very few high-mass stars. This is something our theory of star formation will need to explain. ...
Measuring Distance with Spectroscopic Parallax
... stars in Kelvin (in reverse order). When using this graph, remember that the vertical axis is plotted on a logarithmic scale, and note that the tick marks on the horizontal axis are each worth 500 degrees K. 1. Print out the HR diagram. 2. Using a pen or pencil, draw a smooth best-fit curve that run ...
... stars in Kelvin (in reverse order). When using this graph, remember that the vertical axis is plotted on a logarithmic scale, and note that the tick marks on the horizontal axis are each worth 500 degrees K. 1. Print out the HR diagram. 2. Using a pen or pencil, draw a smooth best-fit curve that run ...
9binary1i
... His third law states that the period (P) of the planet’s orbit (in years) squared is equal to the semi-major axis in astronomical units (AU) cubed (1 AU is the Earth-Sun distance) P2 = a3 ...
... His third law states that the period (P) of the planet’s orbit (in years) squared is equal to the semi-major axis in astronomical units (AU) cubed (1 AU is the Earth-Sun distance) P2 = a3 ...
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.