closed-box model
... We will now develop a simple model of the build up of metals in a galaxy over time. We assume that – the galaxy's gas is well-mixed (had the same initial composition everywhere); – the (high-mass) stars return their nucleosynthetic products rapidly, much faster than the time to form a significant fr ...
... We will now develop a simple model of the build up of metals in a galaxy over time. We assume that – the galaxy's gas is well-mixed (had the same initial composition everywhere); – the (high-mass) stars return their nucleosynthetic products rapidly, much faster than the time to form a significant fr ...
Astronomy 535 Stellar Structure Evolution
... Motivation for studying stellar evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution • Fits of models to observations by means of free parameters is standard procedure, but gives unrel ...
... Motivation for studying stellar evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution • Fits of models to observations by means of free parameters is standard procedure, but gives unrel ...
Chapter 8 – Continuous Absorption
... contribute to opacity • Bound-Bound Transitions – absorption or emission of radiation from electrons moving between bound energy levels. • Bound-Free Transitions – the energy of the higher level electron state lies in the continuum or is unbound. • Free-Free Transitions – change the motion of an ele ...
... contribute to opacity • Bound-Bound Transitions – absorption or emission of radiation from electrons moving between bound energy levels. • Bound-Free Transitions – the energy of the higher level electron state lies in the continuum or is unbound. • Free-Free Transitions – change the motion of an ele ...
Major Themes of “ The First Stars ”
... Physical Models of Star Formation at Zero and Very Low Metallicity: Approach: Hydrosims of gas physics in early cosmological halos Key Results: High mass range (~30 - 300) for limiting Z = 0 case. Formation of first low-mass stars depends on prior ionization and/or metal enrichment metals, dust, CMB ...
... Physical Models of Star Formation at Zero and Very Low Metallicity: Approach: Hydrosims of gas physics in early cosmological halos Key Results: High mass range (~30 - 300) for limiting Z = 0 case. Formation of first low-mass stars depends on prior ionization and/or metal enrichment metals, dust, CMB ...
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... We can in principle image H I condensations in the still neutral, prereionization universe using the 21cm line. Several experiments are now being constructed or planned to do this, e.g., the Mileura WideField Array in Australia, or the Square Kilometer Array (SKA) ...
... We can in principle image H I condensations in the still neutral, prereionization universe using the 21cm line. Several experiments are now being constructed or planned to do this, e.g., the Mileura WideField Array in Australia, or the Square Kilometer Array (SKA) ...
Synthetic Stellar Populations Encyclopedia of Astronomy & Astrophysics eaa.iop.org Guy Worthey
... resolution, but for galaxies and clusters outside the local group we generally cannot hope to study the stars in them one by one. Instead, we see the sum of the light from all of the stars. To take this integrated starlight and extract information on the ages or heavy-element abundances requires a m ...
... resolution, but for galaxies and clusters outside the local group we generally cannot hope to study the stars in them one by one. Instead, we see the sum of the light from all of the stars. To take this integrated starlight and extract information on the ages or heavy-element abundances requires a m ...
L21 THE NONSPHERICAL SHAPE OF BETELGEUSE IN THE
... analytical expression for the visibility of such a model is available. This model also has the advantage over a pure ellipse of being able to generate nonzero closure phases, and Figure 1 shows the closure phase differs slightly from zero. The parameters for this model are also given in Table 1 alon ...
... analytical expression for the visibility of such a model is available. This model also has the advantage over a pure ellipse of being able to generate nonzero closure phases, and Figure 1 shows the closure phase differs slightly from zero. The parameters for this model are also given in Table 1 alon ...
Interacting binary stars Properties of some binary stars are
... has too much angular momentum to fall directly onto the surface of the other star: Gas forms an accretion disk around the mass gaining star, through which the gas slowly spirals in before being accreted. This occurs if the accreting star does not have a strong magnetic field. ...
... has too much angular momentum to fall directly onto the surface of the other star: Gas forms an accretion disk around the mass gaining star, through which the gas slowly spirals in before being accreted. This occurs if the accreting star does not have a strong magnetic field. ...
Dynamics
... such as our own Milky Way, progress in STELLAR DYNAMICS would be slow if we had to know the locations of every star before we could calculate the motion of a single star. Fortunately, the problem can be simplified by arguing that the net force on a star does not depend sensitively on the precise loc ...
... such as our own Milky Way, progress in STELLAR DYNAMICS would be slow if we had to know the locations of every star before we could calculate the motion of a single star. Fortunately, the problem can be simplified by arguing that the net force on a star does not depend sensitively on the precise loc ...
6.1 Introduction
... in the gas from which stars have recently formed, such as the Orion nebula. Possibly these most metal-poor stars have been enriched by only one previous generation of stars which themselves presumably formed out of pristine gas. Thus, the chemical composition of the most metal-poor stars known is on ...
... in the gas from which stars have recently formed, such as the Orion nebula. Possibly these most metal-poor stars have been enriched by only one previous generation of stars which themselves presumably formed out of pristine gas. Thus, the chemical composition of the most metal-poor stars known is on ...
16_Testbank
... 8) Describe the four distinct stages in the life track of a solar-mass protostar on the H-R diagram and explain why the track is the shape it is. Answer: 1. The protostar forms from a collapsing dusty molecular cloud. The temperature and luminosity both rise so the cloud moves from the far lower rig ...
... 8) Describe the four distinct stages in the life track of a solar-mass protostar on the H-R diagram and explain why the track is the shape it is. Answer: 1. The protostar forms from a collapsing dusty molecular cloud. The temperature and luminosity both rise so the cloud moves from the far lower rig ...
New Astrophysical Opportunities Exploiting Spatio-Temporal Optical Correlations
... • γ 2 Velorum γ 2 Velorum is a binary consisting of a hot O-type star and a Wolf-Rayet star. The proximity to the O-type star creates a situation where two stellar winds interact, creating a wealth of interesting phenomena such as wind collision zones, wind-blown cavities and eclipses of spectral li ...
... • γ 2 Velorum γ 2 Velorum is a binary consisting of a hot O-type star and a Wolf-Rayet star. The proximity to the O-type star creates a situation where two stellar winds interact, creating a wealth of interesting phenomena such as wind collision zones, wind-blown cavities and eclipses of spectral li ...
History of Star Formation in Local Galaxies
... pause due to reionization (12.6 Gyr, z ≈ 6), but each has a seemingly unique star formation history extending over many Gyr. Why? Differences in DM halo masses, differences in continued infall, tidal forces, stripping? Do the SFHs derived match those predicted by ΛCMD? Lets compare with simulation ...
... pause due to reionization (12.6 Gyr, z ≈ 6), but each has a seemingly unique star formation history extending over many Gyr. Why? Differences in DM halo masses, differences in continued infall, tidal forces, stripping? Do the SFHs derived match those predicted by ΛCMD? Lets compare with simulation ...
Labeling the HR Diagram - Mastering Physics Answers
... Consider three stars that are all identical to the Sun, each one located at a different distance from Earth. Which of the following must be true? ANSWER: The stars all have the same luminosity but different apparent brightness. The stars all have the same apparent brightness but different luminosity ...
... Consider three stars that are all identical to the Sun, each one located at a different distance from Earth. Which of the following must be true? ANSWER: The stars all have the same luminosity but different apparent brightness. The stars all have the same apparent brightness but different luminosity ...
this PDF file
... PTPS is conducted with the 9.2 m Hobby-Eberly Telescope (HET) [4], operated in the queue-scheduled mode [5] and equipped with the High Resolution Spectrograph (HRS, [6]). For PTPS the HRS is used in its R=60 000 resolving power mode with a I2 gas cell. The spectra consist of 46 echelle orders record ...
... PTPS is conducted with the 9.2 m Hobby-Eberly Telescope (HET) [4], operated in the queue-scheduled mode [5] and equipped with the High Resolution Spectrograph (HRS, [6]). For PTPS the HRS is used in its R=60 000 resolving power mode with a I2 gas cell. The spectra consist of 46 echelle orders record ...
Stellar Winds and Hydrodynamic Atmospheres of Stars
... plus stellar evolution models à Synthetic spectra of galxies at high z à as a function of Z, IMF, SFR ...
... plus stellar evolution models à Synthetic spectra of galxies at high z à as a function of Z, IMF, SFR ...
Observational Lower mass limit on stars
... of stars in most cases. To get the mass ratio, we need to compute a spectroscopic orbit for the binaries. From a radial velocity plot, you can determine the mass ratio by using the formula m1/ m2 = K2 / K1. Now, with a little algebra, the mass of the two stars can be determined from kepler’s (Capit ...
... of stars in most cases. To get the mass ratio, we need to compute a spectroscopic orbit for the binaries. From a radial velocity plot, you can determine the mass ratio by using the formula m1/ m2 = K2 / K1. Now, with a little algebra, the mass of the two stars can be determined from kepler’s (Capit ...
Document
... • There are several distinct phases in the life cycle of a star. The evolutionary path depends on the initial mass of the star. • Although there is a continuous range of masses, there are 4 ranges of masses that capture all of the interesting features. ...
... • There are several distinct phases in the life cycle of a star. The evolutionary path depends on the initial mass of the star. • Although there is a continuous range of masses, there are 4 ranges of masses that capture all of the interesting features. ...
UvA-DARE (Digital Academic Repository)
... withh the previous accretion of matter with high angular momentum.(after Habets, 1985). materiall present around these stars, but, probably due to its much lower luminosity, the star of laterr spectral type is no longer able to produce Ha emission. Whenn Be stars are in an 'off' phase, as far as we ...
... withh the previous accretion of matter with high angular momentum.(after Habets, 1985). materiall present around these stars, but, probably due to its much lower luminosity, the star of laterr spectral type is no longer able to produce Ha emission. Whenn Be stars are in an 'off' phase, as far as we ...
2015 SAO Summer Intern AAS Abstracts - Harvard
... hydrogen (2.12 microns) were obtained for six massive star-forming regions within the Milky Way, NGC 6334, G305, G3333, G3264, G3266, and G351. These regions are within 1 − 4 kpc from our solar system. The narrowband flux in Brackett gamma was used as a star-formation tracer to calculate a star-form ...
... hydrogen (2.12 microns) were obtained for six massive star-forming regions within the Milky Way, NGC 6334, G305, G3333, G3264, G3266, and G351. These regions are within 1 − 4 kpc from our solar system. The narrowband flux in Brackett gamma was used as a star-formation tracer to calculate a star-form ...
Open cluster intro
... Download the M26, epoch 1 data, unzip and open with ImageJ. Adjust the contrast: under Image, choose Adjust. Either the “auto” or a manual adjustment should produce a good display of the stars. Pay particular attention to improving the contrast to see the faintest stars possible. We want to measure ...
... Download the M26, epoch 1 data, unzip and open with ImageJ. Adjust the contrast: under Image, choose Adjust. Either the “auto” or a manual adjustment should produce a good display of the stars. Pay particular attention to improving the contrast to see the faintest stars possible. We want to measure ...
5. Star Formation and the Interstellar Medium in the Milky Way
... The matter and energy between the stars, the interstellar medium (ISM), is vitally important to the evolution of galaxies, since it is in this environment that stars are formed, and to this environment that both young and aging stars return matter enriched in the heavy elements that are essential fo ...
... The matter and energy between the stars, the interstellar medium (ISM), is vitally important to the evolution of galaxies, since it is in this environment that stars are formed, and to this environment that both young and aging stars return matter enriched in the heavy elements that are essential fo ...
Notes - Michigan State University
... in degenerate electron gas, pressure does not depend on temperature (why ?) therefore a slight rise in temperature is not compensated by expansion thermonuclear runaway: ...
... in degenerate electron gas, pressure does not depend on temperature (why ?) therefore a slight rise in temperature is not compensated by expansion thermonuclear runaway: ...
Presentation in PDF format.
... An element of gas has pressure P and density ρ. Displace upward by distance δr. Allow to expand adiabatically until pressure within is equal to pressure outside. Release the element. If it continues to move upwards, the layer is convectively unstable. If it remains stationary or sinks, the layer is ...
... An element of gas has pressure P and density ρ. Displace upward by distance δr. Allow to expand adiabatically until pressure within is equal to pressure outside. Release the element. If it continues to move upwards, the layer is convectively unstable. If it remains stationary or sinks, the layer is ...