SPY — The ESO Supernovae Type Ia Progenitor Survey
... of carbon and oxygen with thin layers of hydrogen and/or helium on top, supported by degenerate electron gas. They will cool for billions of years and disappear as small cold clumps into the cosmic background without signs of their once glorious lives. Some white dwarfs will, however, destroy themse ...
... of carbon and oxygen with thin layers of hydrogen and/or helium on top, supported by degenerate electron gas. They will cool for billions of years and disappear as small cold clumps into the cosmic background without signs of their once glorious lives. Some white dwarfs will, however, destroy themse ...
Stars, Galaxies, and the Universe Section 1
... • If a white dwarf star revolves around a red giant, the gravity of the white dwarf may capture gases from the red giant. • As these gases accumulate on the surface of the white dwarf, pressure begins to build up. • This pressure may cause large explosions, called a ...
... • If a white dwarf star revolves around a red giant, the gravity of the white dwarf may capture gases from the red giant. • As these gases accumulate on the surface of the white dwarf, pressure begins to build up. • This pressure may cause large explosions, called a ...
doc - IAC
... There are many species in the Universe that astronomers order, describe and classify according to some taxonomical scheme. Hence, nebulae may be of three types: emission, reflection and absorption. Emission nebulae are clouds of gas and dust that emit red light when heated by radiation from nearby y ...
... There are many species in the Universe that astronomers order, describe and classify according to some taxonomical scheme. Hence, nebulae may be of three types: emission, reflection and absorption. Emission nebulae are clouds of gas and dust that emit red light when heated by radiation from nearby y ...
Measuring Black Hole Masses in Nearby Galaxies with Laser Guide
... south BH (may be low because our stars are young; recently formed in disk) • Tecza et al. (2000) measure 236 km/s integrated over whole 0.8”x0.7” region Plot: Tremaine et al 2002 ...
... south BH (may be low because our stars are young; recently formed in disk) • Tecza et al. (2000) measure 236 km/s integrated over whole 0.8”x0.7” region Plot: Tremaine et al 2002 ...
The End of the Dark Ages
... disk galaxy into the halo and intergalactic medium (IGM) by solving the timedependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution. They find that the shells of the expanding superbubbles quickly trap or attenuate the ionizi ...
... disk galaxy into the halo and intergalactic medium (IGM) by solving the timedependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution. They find that the shells of the expanding superbubbles quickly trap or attenuate the ionizi ...
How much radioactive nickel does ASASSN
... (2002) shows the results of the simulation of non-rotating zero-metallicity models in the helium-core mass range between 65 M⊙ and 135 M⊙. The initial corresponding mainsequence star mass ranges from 140 M⊙ to 260 M⊙. However, the evolutionary parameter space greatly exceeds this grid of very massiv ...
... (2002) shows the results of the simulation of non-rotating zero-metallicity models in the helium-core mass range between 65 M⊙ and 135 M⊙. The initial corresponding mainsequence star mass ranges from 140 M⊙ to 260 M⊙. However, the evolutionary parameter space greatly exceeds this grid of very massiv ...
On the evolution and fate of supermassive stars
... classified as a strongly helium-enriched O-star. A further 12 M⊙ are lost in the part of the track where the stellar effective temperature is below ≃ 10 000K, with a lifetime in this later stage of 0.048 Myr. When the star crosses the HD-limit moving blueward, the hydrogen abundance at its surface i ...
... classified as a strongly helium-enriched O-star. A further 12 M⊙ are lost in the part of the track where the stellar effective temperature is below ≃ 10 000K, with a lifetime in this later stage of 0.048 Myr. When the star crosses the HD-limit moving blueward, the hydrogen abundance at its surface i ...
The Sights of the Deep Sky - Peterborough Astronomical Society
... lives. Most of the stars of the galaxy are dim red stars, much less massive than our Sun, and too faint to see without a large telescope. Stars have “life cycles”. They are born out of cold dust and gas in the Milky Way, then begin shining when they become hot enough in their cores to start turning ...
... lives. Most of the stars of the galaxy are dim red stars, much less massive than our Sun, and too faint to see without a large telescope. Stars have “life cycles”. They are born out of cold dust and gas in the Milky Way, then begin shining when they become hot enough in their cores to start turning ...
Gaps
... The spectroscopic approach POSSIBLE INTERPRETATIONS • Why some blue HB stars are spinning so fast? 1) Angular momentum transferred from the core to the outer envelope: Magnetic braking on MS only affects a star’s envelope (Peterson et al. 1983, Pinsonneault et al. 1991) Problems : Sun (Corbard et a ...
... The spectroscopic approach POSSIBLE INTERPRETATIONS • Why some blue HB stars are spinning so fast? 1) Angular momentum transferred from the core to the outer envelope: Magnetic braking on MS only affects a star’s envelope (Peterson et al. 1983, Pinsonneault et al. 1991) Problems : Sun (Corbard et a ...
Measuring the Milky Way
... These objects are very close to the Galactic center. The orbit on the right is the best fit; it assumes a central black hole of 3.7 million solar masses. ...
... These objects are very close to the Galactic center. The orbit on the right is the best fit; it assumes a central black hole of 3.7 million solar masses. ...
Navigating the Night Sky – Teacher Guide Argos Online Subject
... o Why are the stars different sizes on the map? -Different magnitudes (brightness). Stars whose magnitudes are larger numbers are dimmer. The Greeks labeled the brightest stars they could see as magnitude 1 and the faintest as magnitude 6. We still use this system, but it often confuses people. The ...
... o Why are the stars different sizes on the map? -Different magnitudes (brightness). Stars whose magnitudes are larger numbers are dimmer. The Greeks labeled the brightest stars they could see as magnitude 1 and the faintest as magnitude 6. We still use this system, but it often confuses people. The ...
Energy in The Universe - Physics Department, Princeton University
... Every mass large enough to be capable of gravitational collapse must inescap ably pass through a prolonged hydrogen burning phase. The only objects exempt from this rule are masses of planetary size or smaller, in which gravitational contraction is halted by the mechanical incompressibility of the ...
... Every mass large enough to be capable of gravitational collapse must inescap ably pass through a prolonged hydrogen burning phase. The only objects exempt from this rule are masses of planetary size or smaller, in which gravitational contraction is halted by the mechanical incompressibility of the ...
5 April 2012—Gravitational waves 12 Apr 2012 Radiation from a source
... The behavior P ∂ P-53 will be discussed the next class. Q: Simplicio: If a system loses energy, it should slow down, not speed up. What is wrong with Simplicio's thinking when applied to the binary pulsar? dPdt ...
... The behavior P ∂ P-53 will be discussed the next class. Q: Simplicio: If a system loses energy, it should slow down, not speed up. What is wrong with Simplicio's thinking when applied to the binary pulsar? dPdt ...
The Stellar Population And Origin Of The Mysterious K.V. Getman
... denotes the Gum Nebula. CG12 (red) is one of the few globules located at high-galactic latitude. The existence of any star forming dark cloud at Galactic location (l,b)=(316,21) is unusual, and the cometary structure of CG12 in such an isolated environment is even more mysterious. There are no repor ...
... denotes the Gum Nebula. CG12 (red) is one of the few globules located at high-galactic latitude. The existence of any star forming dark cloud at Galactic location (l,b)=(316,21) is unusual, and the cometary structure of CG12 in such an isolated environment is even more mysterious. There are no repor ...
Some notes on the Inka constellations
... its location the names and significance of celestial objects. It is important to emphasize that within the astronomy of the Inkas there are two types of constellations: (a) Stellar constellations or bright stars, made up of individual bright stars which constitute a ‘constellation’ and grouped togeth ...
... its location the names and significance of celestial objects. It is important to emphasize that within the astronomy of the Inkas there are two types of constellations: (a) Stellar constellations or bright stars, made up of individual bright stars which constitute a ‘constellation’ and grouped togeth ...
HEA_Pulsars_2002
... - inner ~ 1018 kg m-3 = 1015g cm-3 - M ~ 0.2 - 3.2 solar masses - surface gravity ~ 1012 m s-2 • We are going to find magnetic induction, B, of a neutron star. ...
... - inner ~ 1018 kg m-3 = 1015g cm-3 - M ~ 0.2 - 3.2 solar masses - surface gravity ~ 1012 m s-2 • We are going to find magnetic induction, B, of a neutron star. ...
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.