History of Star Formation in Local Galaxies
... Supergiants • Low Mass Stars evolve and change in both Teff and L → Red Giant/AGB stars • τMS = 10 Gyr x (M/M)–2.5 ...
... Supergiants • Low Mass Stars evolve and change in both Teff and L → Red Giant/AGB stars • τMS = 10 Gyr x (M/M)–2.5 ...
Light and Blackbody radiation
... • Star B is emitting the most light per area. The Stefan-Boltzman law says the Watts/m2 emitted is proportional to the temperature to the fourth power. • We can’t tell which star (A or B) is emitting the most energy in general because that depends on both size and temperature, and we only know the r ...
... • Star B is emitting the most light per area. The Stefan-Boltzman law says the Watts/m2 emitted is proportional to the temperature to the fourth power. • We can’t tell which star (A or B) is emitting the most energy in general because that depends on both size and temperature, and we only know the r ...
PowerPoint file - Adin Community Bible Church
... “The complete birth of a star has never been observed. The principles of physics demand some special conditions for star formation and also for a long time period. A cloud of hydrogen gas must be compressed to a sufficiently small size so that gravity ...
... “The complete birth of a star has never been observed. The principles of physics demand some special conditions for star formation and also for a long time period. A cloud of hydrogen gas must be compressed to a sufficiently small size so that gravity ...
Starbirth - Lincoln-Sudbury Regional High School
... actually “see” inside the cloud. This region has recently been observed with the VLT* at near-infrared wavelengths, which can penetrate the dense dust and reveal the newly born stars. Very young, relatively massive stars are found at the tips of two of the main three pillars, and about a dozen lower ...
... actually “see” inside the cloud. This region has recently been observed with the VLT* at near-infrared wavelengths, which can penetrate the dense dust and reveal the newly born stars. Very young, relatively massive stars are found at the tips of two of the main three pillars, and about a dozen lower ...
mass loss and stellar evolution
... • Because of clumping, mass-loss rates for line-driven winds have been revised downward by an order of magnitude. • Thus, line-driven winds on the main-sequence are vastly insufficient to remove the H envelope and produce WR stars (MWR20 M)…best alternative is that LBV eruptions dominate the mass ...
... • Because of clumping, mass-loss rates for line-driven winds have been revised downward by an order of magnitude. • Thus, line-driven winds on the main-sequence are vastly insufficient to remove the H envelope and produce WR stars (MWR20 M)…best alternative is that LBV eruptions dominate the mass ...
Bolte_LRIS_08A
... VLT/FLAMES facility measured abundances for a large number of giants in the dSph galaxies Sculptor, Fornax, Sextans and Carina. Their results show that while there are large dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrich ...
... VLT/FLAMES facility measured abundances for a large number of giants in the dSph galaxies Sculptor, Fornax, Sextans and Carina. Their results show that while there are large dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrich ...
Radiation from Proxima Centauri
... Radiation from Proxima Centauri. The closest star to the Solar System is known as Proxima Centauri. Its distance has been accurately measured as 4.243 light years [4.01 1016 m]. The strength of the radiation at different wavelengths has been studied by satellites orbiting the Earth and the spectru ...
... Radiation from Proxima Centauri. The closest star to the Solar System is known as Proxima Centauri. Its distance has been accurately measured as 4.243 light years [4.01 1016 m]. The strength of the radiation at different wavelengths has been studied by satellites orbiting the Earth and the spectru ...
Powerpoint for today
... Not enough radiating matter at large R to explain rotation curve => "dark" matter! Dark matter must be about 90% of the mass! Composition unknown. Probably mostly exotic particles that don't interact with ordinary matter at all (except gravity). Some may be brown dwarfs, dead white dwarfs … Most li ...
... Not enough radiating matter at large R to explain rotation curve => "dark" matter! Dark matter must be about 90% of the mass! Composition unknown. Probably mostly exotic particles that don't interact with ordinary matter at all (except gravity). Some may be brown dwarfs, dead white dwarfs … Most li ...
Pulsations in White Dwarfs
... composition (red dots), and that of a model in which stellar winds and gravitational settling are taken into account (black dots). The latter suggests that a GW Vir star (PG1159 spectral type) should again pulsate in its lifetime but, this time, as a much cooler DB white dwarf of the V777 Her type. ...
... composition (red dots), and that of a model in which stellar winds and gravitational settling are taken into account (black dots). The latter suggests that a GW Vir star (PG1159 spectral type) should again pulsate in its lifetime but, this time, as a much cooler DB white dwarf of the V777 Her type. ...
Chapter 6
... by this gas, perhaps augmented by convection, helps to push the shock outward. It is important to note that there are limits to how effective this neutrino energy transfer can be in one-dimensional models: if matter is too far from the core, the coupling to neutrinos is too weak to deposite signific ...
... by this gas, perhaps augmented by convection, helps to push the shock outward. It is important to note that there are limits to how effective this neutrino energy transfer can be in one-dimensional models: if matter is too far from the core, the coupling to neutrinos is too weak to deposite signific ...
Ch. 13 GALAXIES
... III. Formation of the Milky Way A. ______ stars formed before disk B. Disk stars formed later due to _____ of gas/dust by angular momentum ...
... III. Formation of the Milky Way A. ______ stars formed before disk B. Disk stars formed later due to _____ of gas/dust by angular momentum ...
David S. Stevenson
... area of research to which astrophysicists must return. This is all the more true as K-class, orange dwarfs have become targets for searches of habitable worlds. I would also like to offer thanks to the team at www.universetoday.com for their prescient (verging on spooky) ability to publish articles ...
... area of research to which astrophysicists must return. This is all the more true as K-class, orange dwarfs have become targets for searches of habitable worlds. I would also like to offer thanks to the team at www.universetoday.com for their prescient (verging on spooky) ability to publish articles ...
Background Presentation
... The NASA E/PO Program at Sonoma State University A group of people working collaboratively to educate the public about current and future NASA high energy astrophysics/astronomy missions. Swift Led by Prof. Lynn Cominsky ...
... The NASA E/PO Program at Sonoma State University A group of people working collaboratively to educate the public about current and future NASA high energy astrophysics/astronomy missions. Swift Led by Prof. Lynn Cominsky ...
Lecture Notes
... dwarf in a binary system. As the mass approaches the ‘Chandrasekhar limit’ of 1.4M , the increasing temperature and density results in ignition of carbon fusion. This proceeds very rapidly, releasing huge amounts of energy in a few seconds. Because all such ‘Type Ia’ supernovae originate in much th ...
... dwarf in a binary system. As the mass approaches the ‘Chandrasekhar limit’ of 1.4M , the increasing temperature and density results in ignition of carbon fusion. This proceeds very rapidly, releasing huge amounts of energy in a few seconds. Because all such ‘Type Ia’ supernovae originate in much th ...
superbubbles vs super-galactic winds
... Our knowledge of stellar evolution has now been assembled by several groups in order to predict the properties of stellar clusters, given an IMF and a stellar mass range. These are the so called synthesis models of starbursts (Mas-Hesse and Kunth 1991, Leitherer & Heckman 1995) which predict a varie ...
... Our knowledge of stellar evolution has now been assembled by several groups in order to predict the properties of stellar clusters, given an IMF and a stellar mass range. These are the so called synthesis models of starbursts (Mas-Hesse and Kunth 1991, Leitherer & Heckman 1995) which predict a varie ...
The Milky Way Galaxy - Academic Computer Center
... Jupiter’s orbit but with a This is called a supermassive mass several million times black hole. Most other galaxies the mass of the Sun. are also thought to have these huge • Since so little light is visible black holes in their centers. from this object it is thought to be a very large black hole. ...
... Jupiter’s orbit but with a This is called a supermassive mass several million times black hole. Most other galaxies the mass of the Sun. are also thought to have these huge • Since so little light is visible black holes in their centers. from this object it is thought to be a very large black hole. ...
16.1 A Little History
... ble explanations, the most intriguing possibility is that stars more massive than ∼ 17M may collapse ‘quietly’ to form black holes and either very faint supernovae or no supernova at all. ...
... ble explanations, the most intriguing possibility is that stars more massive than ∼ 17M may collapse ‘quietly’ to form black holes and either very faint supernovae or no supernova at all. ...
General Module information
... form a temperature series and roughly estimate the effective temperature, given the spectral class. Explain what is meant by luminosity class, and in particular know the correspondences: Luminosity class Ia Ib II III V wd ...
... form a temperature series and roughly estimate the effective temperature, given the spectral class. Explain what is meant by luminosity class, and in particular know the correspondences: Luminosity class Ia Ib II III V wd ...
Autumn Night sky Guide
... Some objects have already been mentioned which repay more detailed inspection with either binoculars or telescopes. The list is now expanded to include some more objects that can be seen using binoculars. Note that they are also all worth looking at with telescopes. West (refer to figure 2) Epsilon ...
... Some objects have already been mentioned which repay more detailed inspection with either binoculars or telescopes. The list is now expanded to include some more objects that can be seen using binoculars. Note that they are also all worth looking at with telescopes. West (refer to figure 2) Epsilon ...
lesson V - Caesars
... CONTRA means against. To contradict someone is to speak against what they have said; a contrast is a difference between two things, and to be contrary is to go against what is desired of you by others. STELL means star. The stellar surface is the surface of the star; a constellation is a group of st ...
... CONTRA means against. To contradict someone is to speak against what they have said; a contrast is a difference between two things, and to be contrary is to go against what is desired of you by others. STELL means star. The stellar surface is the surface of the star; a constellation is a group of st ...
Monday, April 28
... • there are ~ 100 billion galaxies in the observable Universe • measure distances to other galaxies using the periodluminosity relationship for Cepheid variables • Type I supernovae also used to measure distances – Predictable luminosity – a standard candle ...
... • there are ~ 100 billion galaxies in the observable Universe • measure distances to other galaxies using the periodluminosity relationship for Cepheid variables • Type I supernovae also used to measure distances – Predictable luminosity – a standard candle ...
Counter-rotating Stellar Components in Simulated Disk Galaxies
... major axis shows striking bimodality. This bimodality indicates the presence of two disk components, photometrically inseparable, but counterstreaming at projected velocities of 100km/s and +150km/s (Rix et al 1992) ...
... major axis shows striking bimodality. This bimodality indicates the presence of two disk components, photometrically inseparable, but counterstreaming at projected velocities of 100km/s and +150km/s (Rix et al 1992) ...
Rotation Curve Laboratory
... Part II: Motions of Stars One way to estimate the amount of mass in a spiral galaxy is by looking at how much light the galaxy gives off. Where there is more light there must be more stars and hence more mass. When astronomers measure the amount of light coming from different parts of the galaxy, th ...
... Part II: Motions of Stars One way to estimate the amount of mass in a spiral galaxy is by looking at how much light the galaxy gives off. Where there is more light there must be more stars and hence more mass. When astronomers measure the amount of light coming from different parts of the galaxy, th ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.