Rocky planetesimals as the origin of metals in DZ stars
... obvious pattern is seen, although there may be a higher density of DZA stars near the Galactic disc and perhaps also towards more modest speeds, but the former may be an observational bias due to diminished spectroscopic sensitivity. In any case, one should expect a correlation between these quantit ...
... obvious pattern is seen, although there may be a higher density of DZA stars near the Galactic disc and perhaps also towards more modest speeds, but the former may be an observational bias due to diminished spectroscopic sensitivity. In any case, one should expect a correlation between these quantit ...
observations and theory of star cluster formation
... previously accepted boundaries. This result is consistent with the hierarchical clustering model. 4. Two Examples of Hierarchical Stellar Structure: Orion and W3. There are many observations of individual clusters that are part of a hierarchy on larger scales. The Orion region overall contains at le ...
... previously accepted boundaries. This result is consistent with the hierarchical clustering model. 4. Two Examples of Hierarchical Stellar Structure: Orion and W3. There are many observations of individual clusters that are part of a hierarchy on larger scales. The Orion region overall contains at le ...
Table of Contents - Shawnee State University
... The constellation system that we have today came from the ancient Greeks. The stories, legends and reasons why they came to be in the sky originated the very first moment that man walked this Earth. - The constellations were totally imaginary creatures, beings, and objects that farmers, poets, and a ...
... The constellation system that we have today came from the ancient Greeks. The stories, legends and reasons why they came to be in the sky originated the very first moment that man walked this Earth. - The constellations were totally imaginary creatures, beings, and objects that farmers, poets, and a ...
Word doc - UC-HiPACC - University of California, Santa Cruz
... supernovae—stars exploding in cataclysmic stellar suicide—but did not act like familiar supernovae. Instead of brightening over a period of maybe three weeks (about 20 days), they seemed to take nearly three months (about 80 days). At first, no host galaxy could be found, so Howell and his colleague ...
... supernovae—stars exploding in cataclysmic stellar suicide—but did not act like familiar supernovae. Instead of brightening over a period of maybe three weeks (about 20 days), they seemed to take nearly three months (about 80 days). At first, no host galaxy could be found, so Howell and his colleague ...
Spiral Galaxies: Origin by Gravitational Vectors Merging Theory
... example M 74 (= NGC 628) or M 83 or ESO 269-57. Each of two spiral arms arises from opposite position at the central bulge. Sometimes these arms are splitting up, see NGC 1232 or our Milky Way or M 101. Spiral arms will shine for billions of years. If they consisted permanently of only the same star ...
... example M 74 (= NGC 628) or M 83 or ESO 269-57. Each of two spiral arms arises from opposite position at the central bulge. Sometimes these arms are splitting up, see NGC 1232 or our Milky Way or M 101. Spiral arms will shine for billions of years. If they consisted permanently of only the same star ...
The First Galaxies: Assembly under Radiative Feedback from the
... 2007b; Greif et al. 2008; Regan & Haehnelt 2009). On the other hand, simulations of galaxies inside halos with larger masses & 109 M⊙ and at lower redshifts z . 6 − 10 often find the halo gas organized in rotationally supported disks (e.g., Mashchenko et al. 2008; Pawlik et al. 2011; Romano-Dı́az et ...
... 2007b; Greif et al. 2008; Regan & Haehnelt 2009). On the other hand, simulations of galaxies inside halos with larger masses & 109 M⊙ and at lower redshifts z . 6 − 10 often find the halo gas organized in rotationally supported disks (e.g., Mashchenko et al. 2008; Pawlik et al. 2011; Romano-Dı́az et ...
Chapter 7 in the LSST Science Book
... the y band data will penetrate through the interstellar dust layer. These data will provide constraints on the merger history of the Milky Way and shed light on how the thin disk formed and survived since z = 1. Structure formation in the concordance cosmology model (and the vast majority of suggest ...
... the y band data will penetrate through the interstellar dust layer. These data will provide constraints on the merger history of the Milky Way and shed light on how the thin disk formed and survived since z = 1. Structure formation in the concordance cosmology model (and the vast majority of suggest ...
Chapter 15 Normal and Active Galaxies
... a) the density of galaxies in the universe. b) the luminosity of distant galaxies. c) the reddening of light from dust clouds. d) the speed of a galaxy. e) the rate of expansion of the universe. ...
... a) the density of galaxies in the universe. b) the luminosity of distant galaxies. c) the reddening of light from dust clouds. d) the speed of a galaxy. e) the rate of expansion of the universe. ...
Metal-poor Stars
... The claim for an inhomogeneous interstellar medium was diminished when Cayrel et al. (2004) presented a sample of 35 extremely metal-poor stars. Figure 3 show the abundance trends for those stars for 12 different elements. These authors found very little scatter in the abundance trends of elements w ...
... The claim for an inhomogeneous interstellar medium was diminished when Cayrel et al. (2004) presented a sample of 35 extremely metal-poor stars. Figure 3 show the abundance trends for those stars for 12 different elements. These authors found very little scatter in the abundance trends of elements w ...
ALFALFA H-alpha: The Star-Formation-Rate Density
... SFR (the SFR cannot be directly measured as individual stars cannot be distinguished in galaxies beyond the Local Group). Of these, the optical band is observed most easily as it contains the spectral line of Hα, the strength of which is correlated with galaxian SFR. Hα is emitted when HI gas is ion ...
... SFR (the SFR cannot be directly measured as individual stars cannot be distinguished in galaxies beyond the Local Group). Of these, the optical band is observed most easily as it contains the spectral line of Hα, the strength of which is correlated with galaxian SFR. Hα is emitted when HI gas is ion ...
Course Outline - Tony Bacigalupo
... populated with stars at the center of the Galaxy The interstellar medium blocks our view of the center The center of the Galaxy is in the direction of Sagittarius ...
... populated with stars at the center of the Galaxy The interstellar medium blocks our view of the center The center of the Galaxy is in the direction of Sagittarius ...
here - NASA/IPAC Extragalactic Database
... the relative number of evolved massive stars of various kinds, such as the relative number of Wolf-Rayet stars to red supergiants, or the relative number of WC- and WN-type WRs. Secondly, these massive stars affect the overall evolution and properties of the galaxies themselves, through three “feedb ...
... the relative number of evolved massive stars of various kinds, such as the relative number of Wolf-Rayet stars to red supergiants, or the relative number of WC- and WN-type WRs. Secondly, these massive stars affect the overall evolution and properties of the galaxies themselves, through three “feedb ...
Chapter 1 - Princeton University Press
... Hubble studied the Andromeda Nebula, which had been thought by many, including Shapley, to be a gas cloud within the Milky Way. The word nebula comes from the Latin nubes, or “cloud,” denoting the fuzzy appearance of these objects. By careful observations with the new 100-inch telescope, Hubble disc ...
... Hubble studied the Andromeda Nebula, which had been thought by many, including Shapley, to be a gas cloud within the Milky Way. The word nebula comes from the Latin nubes, or “cloud,” denoting the fuzzy appearance of these objects. By careful observations with the new 100-inch telescope, Hubble disc ...
ASTRONOMY 113 Laboratory Lab 5: Spectral Classification of the
... characteristics, we can transfer knowledge gleaned about any star in the group to all stars in the group. At the same time, unusual cases may be readily identified by the very fact that they cannot be classified. Such peculiar objects are typically subjected to intensive study, and very often reveal ...
... characteristics, we can transfer knowledge gleaned about any star in the group to all stars in the group. At the same time, unusual cases may be readily identified by the very fact that they cannot be classified. Such peculiar objects are typically subjected to intensive study, and very often reveal ...
Feedback from winds and supernovae in massive stellar clusters – I
... Published by Oxford University Press on behalf of the Royal Astronomical Society ...
... Published by Oxford University Press on behalf of the Royal Astronomical Society ...
Chromospherically young, kinematically old stars
... case of normal active stars, which are presumably young. This is an effect of the asymmetrical drift. The stars are likely to acquire increasing random velocities with respect to the local standard of rest, due to subsequent encounters with giant molecular clouds. In U and W , there will be a symmet ...
... case of normal active stars, which are presumably young. This is an effect of the asymmetrical drift. The stars are likely to acquire increasing random velocities with respect to the local standard of rest, due to subsequent encounters with giant molecular clouds. In U and W , there will be a symmet ...
The Life of the Sun
... Helium Flash. At this point the Sun becomes what we call a Horizontal Branch Star. Now you have a new segment in the evolution of the Sun. This phase can also be called the sub-giant phase of the Star. Here you have the Star happily burning Helium, it bloats itself back out. It gets hotter in the co ...
... Helium Flash. At this point the Sun becomes what we call a Horizontal Branch Star. Now you have a new segment in the evolution of the Sun. This phase can also be called the sub-giant phase of the Star. Here you have the Star happily burning Helium, it bloats itself back out. It gets hotter in the co ...
Section 2
... headlights? (The one closer to you) Does this mean that its headlights are actually brighter? (Not necessarily; the headlights on the other car may be the same brightness but appear dimmer because of distance.) Teach Explain that a star may appear to be brighter than another star because it is close ...
... headlights? (The one closer to you) Does this mean that its headlights are actually brighter? (Not necessarily; the headlights on the other car may be the same brightness but appear dimmer because of distance.) Teach Explain that a star may appear to be brighter than another star because it is close ...
Properties of Wolf-Rayet Stars - Paul Crowther, University of Sheffield
... Visual spectral classification of WR stars is based on emission line strengths and line ratios (Smith 1968). To date, high-ionization WN2 to WN5 are known as ‘early WN’ (WNE) stars, and low-ionization WN7 to WN9(–11) stars known as ‘late WN’ (WNL) stars, and WN6 stars either early or late-type. Comp ...
... Visual spectral classification of WR stars is based on emission line strengths and line ratios (Smith 1968). To date, high-ionization WN2 to WN5 are known as ‘early WN’ (WNE) stars, and low-ionization WN7 to WN9(–11) stars known as ‘late WN’ (WNL) stars, and WN6 stars either early or late-type. Comp ...
Flatfielding chapter for Calibration Volumes
... The following discussion assumes that we can control the telescope well enough to point it to a particular sub-pixel location reliably. If that is not the case, then we should simply command the telescope to move by a pixel or so between each exposure and take whatever random dithering we get. We wi ...
... The following discussion assumes that we can control the telescope well enough to point it to a particular sub-pixel location reliably. If that is not the case, then we should simply command the telescope to move by a pixel or so between each exposure and take whatever random dithering we get. We wi ...
Unravelling the Origin and Evolution of Our Galaxy
... unexpected orbits. Theories of planetary formation developed to explain the formation of our own Solar System predicted that they would not form so close to the central star, where temperatures are high, and where the amount of protoplanetary disc matter was believed to be small. A transit across th ...
... unexpected orbits. Theories of planetary formation developed to explain the formation of our own Solar System predicted that they would not form so close to the central star, where temperatures are high, and where the amount of protoplanetary disc matter was believed to be small. A transit across th ...
A new view of galaxy evolution
... internal motion similar to nearby disc/ellipticals – further evidence for their violent origin. There are other clues we must consider. One is that these galaxies are undergoing intense star formation with on the order of a few hundred solar masses of new stars formed per year, compared with just a ...
... internal motion similar to nearby disc/ellipticals – further evidence for their violent origin. There are other clues we must consider. One is that these galaxies are undergoing intense star formation with on the order of a few hundred solar masses of new stars formed per year, compared with just a ...
Title: Binary interaction dominates the evolution of massive stars
... §A). With 40 identified spectroscopic binaries, the observed binary fraction in our sample is fobs = 40/71 = 0.56. We combined observations obtained with the Ultraviolet and Visible Echelle Spectrograph (UVES) at the Very Large Telescope for long-period systems with results from detailed studies of ...
... §A). With 40 identified spectroscopic binaries, the observed binary fraction in our sample is fobs = 40/71 = 0.56. We combined observations obtained with the Ultraviolet and Visible Echelle Spectrograph (UVES) at the Very Large Telescope for long-period systems with results from detailed studies of ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.