Chapter 14 The Milky Way Galaxy
... correlated with the period of their oscillations; once the period is measured, the luminosity is known and we can proceed as above. ...
... correlated with the period of their oscillations; once the period is measured, the luminosity is known and we can proceed as above. ...
1.2.43The stellar populations of the Milky Way
... stars, which is consistent with star formation in the spheroid ceasing long ago. Because this population is so old, only low-mass stars (which have long lifetimes) still shine as main sequence stars burning hydrogen in their cores. The more massive stars that formed at the same time as the surviving ...
... stars, which is consistent with star formation in the spheroid ceasing long ago. Because this population is so old, only low-mass stars (which have long lifetimes) still shine as main sequence stars burning hydrogen in their cores. The more massive stars that formed at the same time as the surviving ...
V - ESO
... This is generally assumed to be the reason why, though star formation proceeds on a typical scale comparable to the size of a giant molecular cloud (~80 pc, Efremov 1995, AJ 100, 2757), Milky Way massive clusters tend to be much smaller. Image taken from class by James Schombert, University of Oreg ...
... This is generally assumed to be the reason why, though star formation proceeds on a typical scale comparable to the size of a giant molecular cloud (~80 pc, Efremov 1995, AJ 100, 2757), Milky Way massive clusters tend to be much smaller. Image taken from class by James Schombert, University of Oreg ...
Measuring the masses of clusters
... Masses of clusters from x-ray gas: •! If we assume the cluster is in hydrostatic equilibrium, #=density of the gas, P=pressure ...
... Masses of clusters from x-ray gas: •! If we assume the cluster is in hydrostatic equilibrium, #=density of the gas, P=pressure ...
3-color photometry of stellar cluster - Kiepenheuer
... a size of 0.3 to 10 parsecs. These clusters are normally 10 times larger than open clusters and the total size is between 20 to 150 parsecs. They are located mostly inside the halo of galaxies and so do not follow the galactic rotation but have their own random elliptic orbits (Weigert and Wendker, ...
... a size of 0.3 to 10 parsecs. These clusters are normally 10 times larger than open clusters and the total size is between 20 to 150 parsecs. They are located mostly inside the halo of galaxies and so do not follow the galactic rotation but have their own random elliptic orbits (Weigert and Wendker, ...
The Milky Way Galaxy
... • The light year is a measure of distance. • Light travels 186,282 miles in one second. • A light year is the distance that light travels in one year, or 5,880,000,000,000 miles. ...
... • The light year is a measure of distance. • Light travels 186,282 miles in one second. • A light year is the distance that light travels in one year, or 5,880,000,000,000 miles. ...
The Milky Way Galaxy
... Since a galaxy is a system of stars, one way is to just count fainter and fainter stars in all directions. Once I reach the most distant stars (which appear as the faintest) at the edge of the system, I find no more fainter stars. By repeating this procedure along all directions, I can get an idea o ...
... Since a galaxy is a system of stars, one way is to just count fainter and fainter stars in all directions. Once I reach the most distant stars (which appear as the faintest) at the edge of the system, I find no more fainter stars. By repeating this procedure along all directions, I can get an idea o ...
Stellar Pops 2
... evolution histories for very large sample of galaxies throughout the Hubble sequence. – Did star formation comence at the same time thoughout the volume of space to the Virgo Cluster? – What are the star-formation histories for gE galaxies? – Is there a Universal `floor’ to the MDF? – Are there IMF ...
... evolution histories for very large sample of galaxies throughout the Hubble sequence. – Did star formation comence at the same time thoughout the volume of space to the Virgo Cluster? – What are the star-formation histories for gE galaxies? – Is there a Universal `floor’ to the MDF? – Are there IMF ...
Masses are much harder than distance, luminosity, or temperature
... • Range of different mass stars! ...
... • Range of different mass stars! ...
Ch 11c and 12 ( clusters 3-31-11)
... without having to wait billions of years observing how a single star evolves ...
... without having to wait billions of years observing how a single star evolves ...
Stellar Evolution
... All stars lose mass by some form of stellar wind. The most massive stars have the strongest winds; O- and B-type stars can lose a tenth of their total mass this way in only a million years. These stellar winds hollow out cavities in the interstellar medium surrounding giant stars. ...
... All stars lose mass by some form of stellar wind. The most massive stars have the strongest winds; O- and B-type stars can lose a tenth of their total mass this way in only a million years. These stellar winds hollow out cavities in the interstellar medium surrounding giant stars. ...
HR Diagram, Star Clusters, and Stellar Evolution
... expanding shell of gas that is known as a planetary nebula (PN) ...
... expanding shell of gas that is known as a planetary nebula (PN) ...
PPT - Yale University
... Standard accretion disks become inefficient and unstable at radii > 0.1 pc, so if gas is to get into such a region from a galactic bulge, its angular momentum must be reduced by at least 3 orders of magnitude in some other way. ...
... Standard accretion disks become inefficient and unstable at radii > 0.1 pc, so if gas is to get into such a region from a galactic bulge, its angular momentum must be reduced by at least 3 orders of magnitude in some other way. ...
Chapter 17
... B. they are all at the same distance. C. they are all in the field of view of the galaxy center. D. as a class, they have similar luminosities. 17. The "orbits" of the stars in our galaxy do not follow the laws of Kepler. We understand this to be due to: A. proportionally more mass distributed away ...
... B. they are all at the same distance. C. they are all in the field of view of the galaxy center. D. as a class, they have similar luminosities. 17. The "orbits" of the stars in our galaxy do not follow the laws of Kepler. We understand this to be due to: A. proportionally more mass distributed away ...
lab 11 only - Penn State University
... The celestial sphere is divided up in a system like the \longitude-latitude" system on the Earth's surface. The latitude of an object in the sky is called the declination; an object (like Polaris) whose position is over the Earth's north pole has a declination of +90 degrees; an object over the sout ...
... The celestial sphere is divided up in a system like the \longitude-latitude" system on the Earth's surface. The latitude of an object in the sky is called the declination; an object (like Polaris) whose position is over the Earth's north pole has a declination of +90 degrees; an object over the sout ...
Extragalactic Astrophysics 1 AA 2011-2012 Prof. LA Antonelli
... on the contrary, stars and globular clusters born during collapse do not lose a significant amount of energy in collisions and move on elongated orbits with random orientations, and with negligible total angular momentum Bulge stars are younger than globular clusters (age < ~8-10 Gyr). they could ha ...
... on the contrary, stars and globular clusters born during collapse do not lose a significant amount of energy in collisions and move on elongated orbits with random orientations, and with negligible total angular momentum Bulge stars are younger than globular clusters (age < ~8-10 Gyr). they could ha ...
The Next 2-3 Weeks
... Important to read through Chapter 17 (Relativity) before I start lecturing on it. Pay particular attention to 17.2 “Intervals & Geodesics” • What is a metric? • The Schwarzschild metric (= non-rotating black hole) • “The orbit of a satellite” (somewhat flakey example) I will present additional mater ...
... Important to read through Chapter 17 (Relativity) before I start lecturing on it. Pay particular attention to 17.2 “Intervals & Geodesics” • What is a metric? • The Schwarzschild metric (= non-rotating black hole) • “The orbit of a satellite” (somewhat flakey example) I will present additional mater ...
Constituents of the Milky Way
... For individual stars that aren’t in clusters (like the Sun), we can’t use the cluster turnoff method to measure an age. For instance, a lone G star might be young, or it might be 10 billion years old. How do we measure its age? The universe contained only hydrogen, helium, and one other element (lit ...
... For individual stars that aren’t in clusters (like the Sun), we can’t use the cluster turnoff method to measure an age. For instance, a lone G star might be young, or it might be 10 billion years old. How do we measure its age? The universe contained only hydrogen, helium, and one other element (lit ...
Question 1
... Question 1 The location of the Galactic center was identified early in the 20th century using a) supernova remnants. b) white dwarf stars in the spiral arms. c) red giant variable stars in globular clusters. d) bright O and B stars in open clusters. e) X-ray sources. Explanation: Harlow Shapley use ...
... Question 1 The location of the Galactic center was identified early in the 20th century using a) supernova remnants. b) white dwarf stars in the spiral arms. c) red giant variable stars in globular clusters. d) bright O and B stars in open clusters. e) X-ray sources. Explanation: Harlow Shapley use ...
Unit 1
... • Stars form in large groups out of a single interstellar cloud of gas and dust • These groups are called star clusters • Open clusters have a low density of stars – there is lots of space between the cluster’s members • They can contain up to a few thousand stars in a volume 14 to 40 light years ac ...
... • Stars form in large groups out of a single interstellar cloud of gas and dust • These groups are called star clusters • Open clusters have a low density of stars – there is lots of space between the cluster’s members • They can contain up to a few thousand stars in a volume 14 to 40 light years ac ...
Today`s Powerpoint
... - contains globular clusters, old stars, little gas and dust, much "dark matter" - roughly spherical ...
... - contains globular clusters, old stars, little gas and dust, much "dark matter" - roughly spherical ...
MSci Astrophysics 210PHY412 - Queen's University Belfast
... differs enormously. We can divide the HRD into four sections, defined by mass ranges within which the evolution is similar (or related). ...
... differs enormously. We can divide the HRD into four sections, defined by mass ranges within which the evolution is similar (or related). ...
Astrophysical parameters of ten poorly studied open star clusters
... with the 2MASS J, H and Ks filters (Bonatto et al. 2004; Bica et al. 2006) to derive the cluster parameters. The simultaneous fittings were attempted on the J ∼ (J − H) and Ks ∼ (J − Ks ) diagrams for the inner stars, which should be less contaminated by the background field. If the number of stars ...
... with the 2MASS J, H and Ks filters (Bonatto et al. 2004; Bica et al. 2006) to derive the cluster parameters. The simultaneous fittings were attempted on the J ∼ (J − H) and Ks ∼ (J − Ks ) diagrams for the inner stars, which should be less contaminated by the background field. If the number of stars ...
Milky Way I
... • Most stars in our neighborhood are cool, low mass stars • There are no massive (O or B) stars nearby • The interstellar gas in our neighborhood is still quite hot It is a graveyard of recent massive star deaths. ...
... • Most stars in our neighborhood are cool, low mass stars • There are no massive (O or B) stars nearby • The interstellar gas in our neighborhood is still quite hot It is a graveyard of recent massive star deaths. ...
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is derived from the Latin globulus—a small sphere. A globular cluster is sometimes known more simply as a globular.Globular clusters, which are found in the halo of a galaxy, contain considerably more stars and are much older than the less dense galactic, or open clusters, which are found in the disk. Globular clusters are fairly common; there are about 150 to 158 currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered. These globular clusters orbit the Galaxy at radii of 40 kiloparsecs (130,000 light-years) or more. Larger galaxies can have more: Andromeda, for instance, may have as many as 500. Some giant elliptical galaxies, particularly those at the centers of galaxy clusters, such as M87, have as many as 13,000 globular clusters.Every galaxy of sufficient mass in the Local Group has an associated group of globular clusters, and almost every large galaxy surveyed has been found to possess a system of globular clusters. The Sagittarius Dwarf galaxy and the disputed Canis Major Dwarf galaxy appear to be in the process of donating their associated globular clusters (such as Palomar 12) to the Milky Way. This demonstrates how many of this galaxy's globular clusters might have been acquired in the past.Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their origins and their role in galactic evolution are still unclear. It does appear clear that globular clusters are significantly different from dwarf elliptical galaxies and were formed as part of the star formation of the parent galaxy rather than as a separate galaxy. However, recent conjectures by astronomers suggest that globular clusters and dwarf spheroidals may not be clearly separate and distinct types of objects.