AN INTRODUCTION TO ASTRONOMY Dr. Uri Griv •
... Explanation: How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured on the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741, is known as a ring galaxy and was caused ...
... Explanation: How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured on the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741, is known as a ring galaxy and was caused ...
PART 3 Galaxies
... – Younger, blue, “Population I” stars were found mostly in the disks and spiral arms. Typically less than a few billion years old; Follow circular orbits in the galactic plane – Older, red, “Population II” stars were found mostly in the halo and ...
... – Younger, blue, “Population I” stars were found mostly in the disks and spiral arms. Typically less than a few billion years old; Follow circular orbits in the galactic plane – Older, red, “Population II” stars were found mostly in the halo and ...
Distances
... the standard of rest defined by stars in our neighborhood; for example, over an interval of 50 yr this yields a baseline of 200 AU, so the resulting secular parallax is 100 times the trigonometric parallax. The catch is that other stars also move with respect to the standard of rest, so there’s no w ...
... the standard of rest defined by stars in our neighborhood; for example, over an interval of 50 yr this yields a baseline of 200 AU, so the resulting secular parallax is 100 times the trigonometric parallax. The catch is that other stars also move with respect to the standard of rest, so there’s no w ...
64 Exercise Solutions_e
... Options A and C are incorrect. Since the stars have the same luminosity, Q must be farther away so that it looks fainter. By , the intensity is inversely proportional to the distance squared. Therefore, Q’s distance should be 5 times that of P such that its brightness is 1/52 = 1/25 that of P. ...
... Options A and C are incorrect. Since the stars have the same luminosity, Q must be farther away so that it looks fainter. By , the intensity is inversely proportional to the distance squared. Therefore, Q’s distance should be 5 times that of P such that its brightness is 1/52 = 1/25 that of P. ...
presentation02 - School of Physical Sciences
... The expansion of the universe can be viewed as stretching the spacetime fabric of the universe. “It is He … who stretches out the heavens like a curtain and spreads them out like a tent to dwell in.” – ...
... The expansion of the universe can be viewed as stretching the spacetime fabric of the universe. “It is He … who stretches out the heavens like a curtain and spreads them out like a tent to dwell in.” – ...
Teresa Ashcraft
... evolutionary trend of the IRX and SSFR - IRX found from gas surface density and metallicity - metallicity grows with time - SFR determined by exponentially falling gas density The rise in the SFR density to z=1 is due to Galaxies in the mass range of the turnoff mass (10.5-11.5) Use IRX as a too ...
... evolutionary trend of the IRX and SSFR - IRX found from gas surface density and metallicity - metallicity grows with time - SFR determined by exponentially falling gas density The rise in the SFR density to z=1 is due to Galaxies in the mass range of the turnoff mass (10.5-11.5) Use IRX as a too ...
"Star Tracks", Leaflet for Royal Society Summer Exhibition
... history of the Galaxy? For instance, we would like to know where and when the Sun was born. An individual star experiences many different Galactic environments throughout its life. Spiral arms can cause stars to move from one orbit to another as they age, so by studying the correlation between age a ...
... history of the Galaxy? For instance, we would like to know where and when the Sun was born. An individual star experiences many different Galactic environments throughout its life. Spiral arms can cause stars to move from one orbit to another as they age, so by studying the correlation between age a ...
Lecture 28 - Empyrean Quest Publishers
... that a highly concentrated spherical mass would shrink to a point and have an event horizon around it beyond which nothing could escape (Vescape> c). The Schwarzschild radius, R(event horizon) = 3 km x mass (in solar masses). Oppenheimer (~1940) demonstrated that a stellar remnant above 3 solar mass ...
... that a highly concentrated spherical mass would shrink to a point and have an event horizon around it beyond which nothing could escape (Vescape> c). The Schwarzschild radius, R(event horizon) = 3 km x mass (in solar masses). Oppenheimer (~1940) demonstrated that a stellar remnant above 3 solar mass ...
Emission and reflection nebula are two types of star forming
... Emission and reflection nebula are two types of star forming??? nebula [plural uses “ae”] that can be distinguished between through spectrometry. Through photographing specific nebula using visible light and Hydrogen Alpha filters, calibrating and processing the images[omit for abstract], and analyz ...
... Emission and reflection nebula are two types of star forming??? nebula [plural uses “ae”] that can be distinguished between through spectrometry. Through photographing specific nebula using visible light and Hydrogen Alpha filters, calibrating and processing the images[omit for abstract], and analyz ...
The First Stars in the Universe
... energy to counteract gravity. Because of the more compact structure, the surface layers of the star would also be hotter. In collaboration with Rolf-Peter Kudritzki of the University of Hawaii and Abraham Loeb of Harvard, one of us (Bromm) devised theoretical models of such stars with masses betwee ...
... energy to counteract gravity. Because of the more compact structure, the surface layers of the star would also be hotter. In collaboration with Rolf-Peter Kudritzki of the University of Hawaii and Abraham Loeb of Harvard, one of us (Bromm) devised theoretical models of such stars with masses betwee ...
BIL3: YILDIZ
... Binarity is one of the essential tools for determination of structure and evolution of stars. Binaries in clusters are peerless. Differentially rotating models is in better agreement with the observations than the NR models or models rotating like a solid body. ...
... Binarity is one of the essential tools for determination of structure and evolution of stars. Binaries in clusters are peerless. Differentially rotating models is in better agreement with the observations than the NR models or models rotating like a solid body. ...
Chapter 5 Nuclear reactions in stars
... laws of thermodynamics. Eq. (6.4) is generalized to include both the cases of radiative and convective energy transport. The term ∆∇ is the superadiabaticity of the temperature gradient that must follow from a theory of convection (in practice, the mixing length theory); for the interior one can ta ...
... laws of thermodynamics. Eq. (6.4) is generalized to include both the cases of radiative and convective energy transport. The term ∆∇ is the superadiabaticity of the temperature gradient that must follow from a theory of convection (in practice, the mixing length theory); for the interior one can ta ...
Lecture17
... Energy is generated through fusion in the core of the star which extends 1/4 of the way to the surface The core contains 1/3 of the mass of the star Temperatures reach 15 million K and the density is 150 times the density of water The energy is transported toward the surface by radiation until it re ...
... Energy is generated through fusion in the core of the star which extends 1/4 of the way to the surface The core contains 1/3 of the mass of the star Temperatures reach 15 million K and the density is 150 times the density of water The energy is transported toward the surface by radiation until it re ...
The Formation of Low Mass Stars: Overview and Recent
... Massive clusters form in regions of high ...
... Massive clusters form in regions of high ...
NAME
... ____ 20. What type of standard candle is used to determine distances to globular clusters? a. O-type main-sequence stars b. Cepheid variable stars c. T Tauri stars d. Type I supernovae e. RR Lyrae stars ____ 21. By comparing globular clusters, you find that Cluster A’s RR Lyrae stars are 100 times f ...
... ____ 20. What type of standard candle is used to determine distances to globular clusters? a. O-type main-sequence stars b. Cepheid variable stars c. T Tauri stars d. Type I supernovae e. RR Lyrae stars ____ 21. By comparing globular clusters, you find that Cluster A’s RR Lyrae stars are 100 times f ...
Study Guide for the Final Exam
... We can determine the distance to a relatively near star using parallax - explain exactly how this is done! Can we use light-years to measure that distance? (Or must we determine using parallax, and then CONVERT to light-years?) What is the importance of the A.U. in this technique? What is a parsec? ...
... We can determine the distance to a relatively near star using parallax - explain exactly how this is done! Can we use light-years to measure that distance? (Or must we determine using parallax, and then CONVERT to light-years?) What is the importance of the A.U. in this technique? What is a parsec? ...
Progenitor stars of supernovae
... SN 2006X- Nature of progenitor? •Type Ia supernova (Thermonuclear supernova) •True nature of progenitor star system? •What serves as a companion star? •How to detect signatures of the binary system? •Single degenerate or double degenerate system? ...
... SN 2006X- Nature of progenitor? •Type Ia supernova (Thermonuclear supernova) •True nature of progenitor star system? •What serves as a companion star? •How to detect signatures of the binary system? •Single degenerate or double degenerate system? ...
Slide 1
... black holes GRBs probably will not occur at solar metallicity, if we need a direct collapse to black hole. At lower metallicities, weaker winds allow more massive cores. Below ~0.4 ZSun, the stars cannot loose the He envelope (Heger 2003). Star is either born rotating rapidly, or is spun up by inter ...
... black holes GRBs probably will not occur at solar metallicity, if we need a direct collapse to black hole. At lower metallicities, weaker winds allow more massive cores. Below ~0.4 ZSun, the stars cannot loose the He envelope (Heger 2003). Star is either born rotating rapidly, or is spun up by inter ...
five minute episode script
... DEAN: SINCE THE LITTLE DIPPER HAS SOME VERY FAINT STARS, FINDING THE NORTH STAR CAN BE TOUGH. BUT NEVER FEAR - THE OTHER DIPPER IS HERE! THE BIG DIPPER IS MUCH MORE DISTINCT AND YOU CAN FIND IT ABOUT TO SCOOP THE GROUND IN EARLY EVENING. THE ANCIENT GREEKS AND SOME NATIVE AMERICAN GROUPS CALLED THE ...
... DEAN: SINCE THE LITTLE DIPPER HAS SOME VERY FAINT STARS, FINDING THE NORTH STAR CAN BE TOUGH. BUT NEVER FEAR - THE OTHER DIPPER IS HERE! THE BIG DIPPER IS MUCH MORE DISTINCT AND YOU CAN FIND IT ABOUT TO SCOOP THE GROUND IN EARLY EVENING. THE ANCIENT GREEKS AND SOME NATIVE AMERICAN GROUPS CALLED THE ...
Document
... Centrally condensed stars like our Sun have shallow pulsations Uniform density stars like white dwarfs have deep pulsations ...
... Centrally condensed stars like our Sun have shallow pulsations Uniform density stars like white dwarfs have deep pulsations ...
Hvězdný make up Proč jsou hvězdy skvrnité?
... V901 Ori = HD 37776 – a very young hot star (B2 IV) residing in the emission nebula IC 432, with a complex (quadruple) global magnetic field (Thompson & Landstreet,1985, Kochukhov et al., 2011). ...
... V901 Ori = HD 37776 – a very young hot star (B2 IV) residing in the emission nebula IC 432, with a complex (quadruple) global magnetic field (Thompson & Landstreet,1985, Kochukhov et al., 2011). ...
UNIVERSITY OF SOUTHAMPTON PHYS2013W1 SEMESTER 1
... b) For a giant elliptical galaxy, the wavelength of its Hα line in the observedframe is measured at 659.6 nm with a line width of 0.5 nm. The rest-frame wavelength of the line is at Hα,0 = 656.3 nm. Assuming that the galaxy has no peculiar velocity, show that the galaxy is located at a distance of 2 ...
... b) For a giant elliptical galaxy, the wavelength of its Hα line in the observedframe is measured at 659.6 nm with a line width of 0.5 nm. The rest-frame wavelength of the line is at Hα,0 = 656.3 nm. Assuming that the galaxy has no peculiar velocity, show that the galaxy is located at a distance of 2 ...
Interferometric Doppler Imaging of Chemically Peculiar stars
... All the F stars can be resolved at 1 μm with baselines ≥ 100 m F stars are in the “sweet spot” for angular diameter and hence age measurement: they are bright, near to us, their evolutionary tracks are reliable, and they are still above ZAMS. ...
... All the F stars can be resolved at 1 μm with baselines ≥ 100 m F stars are in the “sweet spot” for angular diameter and hence age measurement: they are bright, near to us, their evolutionary tracks are reliable, and they are still above ZAMS. ...
Document
... emisson spectra and galaxies had continous (stellar) spectra, but no one figured it out. ...
... emisson spectra and galaxies had continous (stellar) spectra, but no one figured it out. ...
Deep HST Imaging of M33: Reliability and Recovery of the Star
... • Stellar evolution tells us how mass, composition, and age of a star are related to luminosity, effective temperature, and composition • Stellar atmosperes tell us how effective temperature, composition, and surface gravity (from mass and luminosity) are related to spectrum/colors • Results embodie ...
... • Stellar evolution tells us how mass, composition, and age of a star are related to luminosity, effective temperature, and composition • Stellar atmosperes tell us how effective temperature, composition, and surface gravity (from mass and luminosity) are related to spectrum/colors • Results embodie ...
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.