SOLUTIONS TO PROBLEM SET # 3
... would be within a Hubble distance of us? Dividing this number of atoms by the volume of space within a Hubble distance of us, show how many hydrogen atoms there would be, on average, per cubic meter of the visible universe. The number of stars within a Hubble distance of us is Nstar = 3.33 × 1022 . ...
... would be within a Hubble distance of us? Dividing this number of atoms by the volume of space within a Hubble distance of us, show how many hydrogen atoms there would be, on average, per cubic meter of the visible universe. The number of stars within a Hubble distance of us is Nstar = 3.33 × 1022 . ...
Available online www.jsaer.com Journal of Scientific and
... When the Sun is close to the horizon, you see it distorted the more, by the Earth’s atmosphere, scattering away the bluer photons and making it appear red. This phenomenon is easily noticeable when sunlight is passed through a prism. It gets scattered into violet, indigo, blue, green, yellow, orange ...
... When the Sun is close to the horizon, you see it distorted the more, by the Earth’s atmosphere, scattering away the bluer photons and making it appear red. This phenomenon is easily noticeable when sunlight is passed through a prism. It gets scattered into violet, indigo, blue, green, yellow, orange ...
January - WVU Planetarium - West Virginia University
... *Sky Chart used with the kind permission of Heavens-Above at http://www.heavens-above.com/ The TOMCHIN PLANETARIUM is named in honor of the late Harold Tomchin, of Princeton, W.Va., who made a generous donation to ensure its continuing operation, and whose family continues to support the planetarium ...
... *Sky Chart used with the kind permission of Heavens-Above at http://www.heavens-above.com/ The TOMCHIN PLANETARIUM is named in honor of the late Harold Tomchin, of Princeton, W.Va., who made a generous donation to ensure its continuing operation, and whose family continues to support the planetarium ...
Rotational spin-up in the 30-Myr
... Pre-Main Sequence (PMS) through the Zero Age Main Sequence (ZAMS) to the mid-MS by the period distributions of low mass members of star forming regions and young open clusters. The changing shape of the rotational distribution as the stars age is relatively well accounted for by these models. Yet, a ...
... Pre-Main Sequence (PMS) through the Zero Age Main Sequence (ZAMS) to the mid-MS by the period distributions of low mass members of star forming regions and young open clusters. The changing shape of the rotational distribution as the stars age is relatively well accounted for by these models. Yet, a ...
Morphological characteristics of OB spectra and environments
... Of spectra are defined by their selective emission lines of He II λ4686 and N III λλ4634– 4640–4642; the gradual development of these features is the basis of the O-type luminosity classification. A few otherwise normal Of supergiants with comparable C III λλ4647–4650– 4652 emission lines had been k ...
... Of spectra are defined by their selective emission lines of He II λ4686 and N III λλ4634– 4640–4642; the gradual development of these features is the basis of the O-type luminosity classification. A few otherwise normal Of supergiants with comparable C III λλ4647–4650– 4652 emission lines had been k ...
Sample - Physics @ IUPUI
... 10) If a neutron star accretes matter from a companion star, how does the spin change? • A) spins faster • B) spins slower • C) spin unchanged • D) stops spinning 11) What are pulsars? • A) rapidly spinning neutron stars • B) rapidly spinning black holes • C) stars that change temperature rapidly • ...
... 10) If a neutron star accretes matter from a companion star, how does the spin change? • A) spins faster • B) spins slower • C) spin unchanged • D) stops spinning 11) What are pulsars? • A) rapidly spinning neutron stars • B) rapidly spinning black holes • C) stars that change temperature rapidly • ...
PH607lec10
... regions, or is produced by energetic electrons moving in magnetic fields Near Infrared: Most of the emission at these wavelengths is from relatively cool giant K stars in the disk and bulge X-rays: extended soft X-ray emission is detected from hot, shocked gas. At the lower energies especially, the ...
... regions, or is produced by energetic electrons moving in magnetic fields Near Infrared: Most of the emission at these wavelengths is from relatively cool giant K stars in the disk and bulge X-rays: extended soft X-ray emission is detected from hot, shocked gas. At the lower energies especially, the ...
Stellar Evolution
... • “The hourglass shapes of many planetary nebulae are produced by the expansion of a ‘fast stellar wind’ within a slowly expanding ’cloud’ which is denser near its equator than its poles.” • If so, where do the x-rays come from? ...
... • “The hourglass shapes of many planetary nebulae are produced by the expansion of a ‘fast stellar wind’ within a slowly expanding ’cloud’ which is denser near its equator than its poles.” • If so, where do the x-rays come from? ...
Introduction to Astronomy and the Celestial Sphere
... appears as a dome over our heads. Stars seem embedded like tiny jewels Ancient astronomers believed that all of the stars were the same distance from the earth (but, of course, they aren’t). Useful model of what we see from Earth. At any one time, we can see only ½ of the celestial sphere (Where is ...
... appears as a dome over our heads. Stars seem embedded like tiny jewels Ancient astronomers believed that all of the stars were the same distance from the earth (but, of course, they aren’t). Useful model of what we see from Earth. At any one time, we can see only ½ of the celestial sphere (Where is ...
Answers - Physics
... 10) If a neutron star accretes matter from a companion star, how does the spin change? • A) spins faster • B) spins slower • C) spin unchanged • D) stops spinning 11) What are pulsars? • A) rapidly spinning neutron stars • B) rapidly spinning black holes • C) stars that change temperature rapidly • ...
... 10) If a neutron star accretes matter from a companion star, how does the spin change? • A) spins faster • B) spins slower • C) spin unchanged • D) stops spinning 11) What are pulsars? • A) rapidly spinning neutron stars • B) rapidly spinning black holes • C) stars that change temperature rapidly • ...
Spring and Summer Sky Observer
... light years deep at the slightly bulging center. A light year is the distance light travels in a year, or about 5.9 million miles. Because Earth is part of the Milky Way, we cannot view the entire structure. However, one side of our galaxy is visible as a starry band across the night sky. Clusters a ...
... light years deep at the slightly bulging center. A light year is the distance light travels in a year, or about 5.9 million miles. Because Earth is part of the Milky Way, we cannot view the entire structure. However, one side of our galaxy is visible as a starry band across the night sky. Clusters a ...
Gamma-Ray Bursts
... explosions known to occur in our Universe. These milliseconds to minutes lasting flashes of gamma-ray photons, the most energetic form of light, release as much energy in their short duration as our Sun will in its entire lifetime. Two classes of GRBs have been identified, with a dividing line in th ...
... explosions known to occur in our Universe. These milliseconds to minutes lasting flashes of gamma-ray photons, the most energetic form of light, release as much energy in their short duration as our Sun will in its entire lifetime. Two classes of GRBs have been identified, with a dividing line in th ...
NEUTRON STARS AND PULSARS Discovery Were it not for
... theory is needed both because the crust on neutron stars is made of iron and nickel nuclei, and the pressure in the interior is so great that nuclei are torn apart into their individual nucleons. A considerable fraction of the nucleons themselves are likely transformed into other types of particles ...
... theory is needed both because the crust on neutron stars is made of iron and nickel nuclei, and the pressure in the interior is so great that nuclei are torn apart into their individual nucleons. A considerable fraction of the nucleons themselves are likely transformed into other types of particles ...
Astronomy 112: The Physics of Stars Class 9 Notes: Polytropes With
... like this is at all sensible. Why should a star ever obey such an equation of state? The answer to this question becomes clearer if we recall that, for an adiabatic gas, the equation of state reads P = Ka ργ a , where Ka is the adiabatic constant and adiabatic index. It is important to understand th ...
... like this is at all sensible. Why should a star ever obey such an equation of state? The answer to this question becomes clearer if we recall that, for an adiabatic gas, the equation of state reads P = Ka ργ a , where Ka is the adiabatic constant and adiabatic index. It is important to understand th ...
Type II supernovae (Inma Dominguez)
... At central He exhaustion, He burning moves to a shell just outside the CO core The following evolution is characterized by the development of a convective He-burning shell limited by the CO core and by the H-burning shell. The chemical composition of this shell, that will be active till the collapse ...
... At central He exhaustion, He burning moves to a shell just outside the CO core The following evolution is characterized by the development of a convective He-burning shell limited by the CO core and by the H-burning shell. The chemical composition of this shell, that will be active till the collapse ...
black hole - Purdue Physics
... Massive star first loses outer layers via a wind, then core collapse occurs (Type II) (Type Ia) ...
... Massive star first loses outer layers via a wind, then core collapse occurs (Type II) (Type Ia) ...
Fe I/Fe II ionization equilibrium in cool stars: NLTE versus LTE
... Abstract. Non-local thermodynamic equilibrium (NLTE) line formation for neutral and singlyionized iron is considered through a range of stellar parameters characteristic of cool stars. A comprehensive model atom for Fe I and Fe II is presented. Our NLTE calculations support the earlier conclusions t ...
... Abstract. Non-local thermodynamic equilibrium (NLTE) line formation for neutral and singlyionized iron is considered through a range of stellar parameters characteristic of cool stars. A comprehensive model atom for Fe I and Fe II is presented. Our NLTE calculations support the earlier conclusions t ...
The 100-billion-body problem A full-scale computer simulation of the
... stars, an O(N 2) algorithm would make 1022 pairwise force calculations on each time step—a task that would keep a billion GRAPE machines busy. Somehow, the number of operations must be drastically reduced. There are several ways to approach this task, but they all involve assembling stars into clust ...
... stars, an O(N 2) algorithm would make 1022 pairwise force calculations on each time step—a task that would keep a billion GRAPE machines busy. Somehow, the number of operations must be drastically reduced. There are several ways to approach this task, but they all involve assembling stars into clust ...
ASTRONOMY AND ASTROPHYSICS How many low
... to be straightforward, dominated by the net production of this light element by low mass stars (i.e., with masses lower than 2 M! ). In these objects, initial D is processed to 3 He during the pre-main sequence phase. Then, as described by Iben (1967), an ...
... to be straightforward, dominated by the net production of this light element by low mass stars (i.e., with masses lower than 2 M! ). In these objects, initial D is processed to 3 He during the pre-main sequence phase. Then, as described by Iben (1967), an ...
bringing pulsating stars into the physics classroom
... Undergraduate physics students at many institutions are never exposed to any aspect of theoretical astrophysics. This is doubly unfortunate because students then miss the opportunity to integrate their knowledge of several disciplines and apply it to interesting astrophysical phenomena. Students fin ...
... Undergraduate physics students at many institutions are never exposed to any aspect of theoretical astrophysics. This is doubly unfortunate because students then miss the opportunity to integrate their knowledge of several disciplines and apply it to interesting astrophysical phenomena. Students fin ...
Pre-supernova evolution of massive stars
... temperature reached is smaller than required for carbon fusion. During the latest stages of evolution on the AGB these stars undergo strong mass loss which removes the remaining envelope, so that their final remnants are C-O white dwarfs. The evolution of massive stars is different in two important ...
... temperature reached is smaller than required for carbon fusion. During the latest stages of evolution on the AGB these stars undergo strong mass loss which removes the remaining envelope, so that their final remnants are C-O white dwarfs. The evolution of massive stars is different in two important ...
How do stars shine?
... It was known through spectroscopy that the Sun was made mostly of hydrogen and helium, so it was a good bet that whatever it was doing involved those elements in some way. Now if you weigh an atom of Helium, it is about four times heavier than an atom of Hydrogen. This is not surprising as everyday ...
... It was known through spectroscopy that the Sun was made mostly of hydrogen and helium, so it was a good bet that whatever it was doing involved those elements in some way. Now if you weigh an atom of Helium, it is about four times heavier than an atom of Hydrogen. This is not surprising as everyday ...
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.