5 - White Dwarfs - University of Texas Astronomy
... The white dwarf could possibly be made of iron that disintegrates upon compression, or, more likely, of oxygen, neon, and magnesium, elements that can absorb electrons rapidly. In these circumstances, when the Chandrasekhar limit is approached, the white dwarf may collapse rather than explode. This ...
... The white dwarf could possibly be made of iron that disintegrates upon compression, or, more likely, of oxygen, neon, and magnesium, elements that can absorb electrons rapidly. In these circumstances, when the Chandrasekhar limit is approached, the white dwarf may collapse rather than explode. This ...
Eyeing the retina nebula
... Planetary nebulae are the multicolored remnants of dead stars. When a star about the size of the Sun runs out of nuclear fuel, the core collapses to form a much smaller dwarf star and the outer layers are ejected to form an expanding cloud of dust and gas. Intense radiation from the collapsed star i ...
... Planetary nebulae are the multicolored remnants of dead stars. When a star about the size of the Sun runs out of nuclear fuel, the core collapses to form a much smaller dwarf star and the outer layers are ejected to form an expanding cloud of dust and gas. Intense radiation from the collapsed star i ...
Solutions - Yale Astronomy
... c) What is the radius of the star compared to that of the earth? (express your answer as a ratio) Since the R = 6.955 × 105 km and R⊕ = 6.378 × 103 km, we can express the radius of the earth with respect to the sun by taking the ratio. We then get that R⊕ = 0.00917R . Now, by substituting this rat ...
... c) What is the radius of the star compared to that of the earth? (express your answer as a ratio) Since the R = 6.955 × 105 km and R⊕ = 6.378 × 103 km, we can express the radius of the earth with respect to the sun by taking the ratio. We then get that R⊕ = 0.00917R . Now, by substituting this rat ...
Slides from the talk
... Neutron star kicks up to several thousands of km/s do not alter the picture. WIMPs remain gravitationally bound to the neutron star within the thermal radius of the last stage of the star (silicon). ...
... Neutron star kicks up to several thousands of km/s do not alter the picture. WIMPs remain gravitationally bound to the neutron star within the thermal radius of the last stage of the star (silicon). ...
star-formation rate
... • The theory of population synthesis aims at interpreting the spectrum of galaxies as a superposition of stellar spectra. • Change of the stellar distribution over time e.g., massive stars leave the main sequence after several 106 years, the number of luminous blue stars thus decreases, so the spect ...
... • The theory of population synthesis aims at interpreting the spectrum of galaxies as a superposition of stellar spectra. • Change of the stellar distribution over time e.g., massive stars leave the main sequence after several 106 years, the number of luminous blue stars thus decreases, so the spect ...
Astronomy news
... The mean density of the companion star is 5x10-5 g cm-3, which is compatible with giant or supergiant star. The ULX in M82 lies close to and possibly within the super star cluster MGG 11. An intermediate-mass black hole may have been formed by stellar collisions in the extremely dense core of MGG 11 ...
... The mean density of the companion star is 5x10-5 g cm-3, which is compatible with giant or supergiant star. The ULX in M82 lies close to and possibly within the super star cluster MGG 11. An intermediate-mass black hole may have been formed by stellar collisions in the extremely dense core of MGG 11 ...
Introduction to Constellations
... Also, as the earth rotates on its axis, the stars which we see are different. The sky at 7pm looks different than the sky at 10pm. Finally, people look at the sky from different locations on the earth see different stars. ...
... Also, as the earth rotates on its axis, the stars which we see are different. The sky at 7pm looks different than the sky at 10pm. Finally, people look at the sky from different locations on the earth see different stars. ...
Introduction to Stars: Their Properties
... Relationship between absolute magnitude and luminosity - bring in the Sun! 41 Cygni’s calculations ...
... Relationship between absolute magnitude and luminosity - bring in the Sun! 41 Cygni’s calculations ...
Lesson 16.3
... the Northern Hemisphere. The half to the south of the equator is called the Southern Hemisphere. The United States is in the Northern Hemisphere. Ursa Major can be seen in the Northern Hemisphere. But people in the Southern Hemisphere cannot see it. The constellation Centaurus can be seen only in th ...
... the Northern Hemisphere. The half to the south of the equator is called the Southern Hemisphere. The United States is in the Northern Hemisphere. Ursa Major can be seen in the Northern Hemisphere. But people in the Southern Hemisphere cannot see it. The constellation Centaurus can be seen only in th ...
Constellations and Asterisms
... puff of light with a slightly brighter center. At times, the ‘eyes’ of the owl can be seen as two slightly darker spots. M101 is called the Pinwheel spiral galaxy. It is a large, 7’ in diameter, face-on spiral with low surface brightness but a brighter core. M108 is an unnamed spiral galaxy extended ...
... puff of light with a slightly brighter center. At times, the ‘eyes’ of the owl can be seen as two slightly darker spots. M101 is called the Pinwheel spiral galaxy. It is a large, 7’ in diameter, face-on spiral with low surface brightness but a brighter core. M108 is an unnamed spiral galaxy extended ...
PowerPoint Presentation - Neutron stars, pulsars and black
... • The discovery of pulsars that were spinning more than 100 times per second (the first was spinning 640 times per second) threw the field for a loop. When some millisecond pulsars were discovered in old star clusters it was even more confusing. • Eventually it was determined that all millisecond pu ...
... • The discovery of pulsars that were spinning more than 100 times per second (the first was spinning 640 times per second) threw the field for a loop. When some millisecond pulsars were discovered in old star clusters it was even more confusing. • Eventually it was determined that all millisecond pu ...
Measuring Stars
... Once many stars are plotted on an H–R diagram, a pattern begins to form: These are the 80 closest stars to us The darkened curve is called the main sequence, as this is where most stars are. Also indicated is the white dwarf region; these stars are hot but not very luminous, as they are quite small. ...
... Once many stars are plotted on an H–R diagram, a pattern begins to form: These are the 80 closest stars to us The darkened curve is called the main sequence, as this is where most stars are. Also indicated is the white dwarf region; these stars are hot but not very luminous, as they are quite small. ...
ppt - 2006 Mitchell Symposium
... All core collapse explosions are significantly polarized, asymmetric. Dynamics, radiative processes (photons, neutrinos) are asymmetric. Account of asymmetry must be made in analysis. Core collapse is an intrinsically shearing environment. Subject to MRI. Rotation and strong magnetic fields are ...
... All core collapse explosions are significantly polarized, asymmetric. Dynamics, radiative processes (photons, neutrinos) are asymmetric. Account of asymmetry must be made in analysis. Core collapse is an intrinsically shearing environment. Subject to MRI. Rotation and strong magnetic fields are ...
5.1 Introduction and Definitions
... gas overlying the opaque interior. The photons produced there carry away the gravitational energy released when the star forms from a collapsing gas cloud, the energy released by the thermonuclear reactions taking place in the core of the star during its lifetime and, once thermonuclear reactions st ...
... gas overlying the opaque interior. The photons produced there carry away the gravitational energy released when the star forms from a collapsing gas cloud, the energy released by the thermonuclear reactions taking place in the core of the star during its lifetime and, once thermonuclear reactions st ...
HR Diagram
... temperature. Use this equation to explain the results you found in the table of the previous question. ...
... temperature. Use this equation to explain the results you found in the table of the previous question. ...
Chapter 5 Galaxies and Star Systems
... the universe. These distant, enormously bright objects looked almost like stars. Since quasi means “something like” in Latin, these objects were given the name quasi-stellar objects, or quasars. Astronomers have concluded that quasars are active young galaxies with giant black holes in their centers ...
... the universe. These distant, enormously bright objects looked almost like stars. Since quasi means “something like” in Latin, these objects were given the name quasi-stellar objects, or quasars. Astronomers have concluded that quasars are active young galaxies with giant black holes in their centers ...
Sun Physics
... the penumbra, which looks lighter gray (if filtered). Sunspots come in cycles, increasing sharply (in numbers) and then decreasing sharply. The period of this solar cycle is about 11 years. (See PPT on ‘The Sun’ for more details.) The sun has enormous organized magnetic fields that reach from pole t ...
... the penumbra, which looks lighter gray (if filtered). Sunspots come in cycles, increasing sharply (in numbers) and then decreasing sharply. The period of this solar cycle is about 11 years. (See PPT on ‘The Sun’ for more details.) The sun has enormous organized magnetic fields that reach from pole t ...
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.