The Milky Way`s Spiral Arms
... useful in studying the Milky Way? • How is the 21 cm line of Hydrogen produced? • Describe the spiral arms of the Milky Way and ...
... useful in studying the Milky Way? • How is the 21 cm line of Hydrogen produced? • Describe the spiral arms of the Milky Way and ...
chapter 24 instructor notes
... In 1837 Argelander, of the Bonn Observatory and orginator of the BD catalogue, was able to derive an apex for the solar motion from studying stellar proper motions. His result is very similar to that recognized today. Also in 1837, Frederick Struve found evidence for interstellar extinction in star ...
... In 1837 Argelander, of the Bonn Observatory and orginator of the BD catalogue, was able to derive an apex for the solar motion from studying stellar proper motions. His result is very similar to that recognized today. Also in 1837, Frederick Struve found evidence for interstellar extinction in star ...
Theory of Massive Star Formation
... • Introduction and observations • Massive star formation models – Fragmentation – Disks and binarity – The radiation pressure problem ...
... • Introduction and observations • Massive star formation models – Fragmentation – Disks and binarity – The radiation pressure problem ...
Life as a Low Mass Red Giant
... just leaving the Main Sequence is called "main sequence turnoff" point. http://www.astro.ubc.ca/~scharein/a311/Sim.html The age of a cluster is just the main sequence lifetime of the stars at the main sequence turnoff • This is about the only way astronomers have to estimate the age of objects outsi ...
... just leaving the Main Sequence is called "main sequence turnoff" point. http://www.astro.ubc.ca/~scharein/a311/Sim.html The age of a cluster is just the main sequence lifetime of the stars at the main sequence turnoff • This is about the only way astronomers have to estimate the age of objects outsi ...
Galaxy Evolution
... • frictional forces drive the gas onto approximately circular orbits in a plane perpendicular to J: it forms a flat disk! • the gas in the disk is denser than if it had retained its near spherical shape, so it is more efficient at cooling and making stars. • we get a spiral galaxy! ...
... • frictional forces drive the gas onto approximately circular orbits in a plane perpendicular to J: it forms a flat disk! • the gas in the disk is denser than if it had retained its near spherical shape, so it is more efficient at cooling and making stars. • we get a spiral galaxy! ...
Summary: Star Formation Near and Far
... How is the collapse of star-forming clumps initiated? A widely accepted view has been that self-gravitating clumps gradually separate from a magnetic field by slow ambipolar diffusion until a configuration approximating a singular isothermal sphere is formed, which then begins to collapse from the i ...
... How is the collapse of star-forming clumps initiated? A widely accepted view has been that self-gravitating clumps gradually separate from a magnetic field by slow ambipolar diffusion until a configuration approximating a singular isothermal sphere is formed, which then begins to collapse from the i ...
Astronomical Distance Ladder
... fairly simple using the standard candle approach. Both types of cepheid variable stars are pulsating stars whose period and luminosity are dependent on the mass of the star. Thus at specific periods every cepheid of one type has the same luminosity. The standard candles approach can be used for supe ...
... fairly simple using the standard candle approach. Both types of cepheid variable stars are pulsating stars whose period and luminosity are dependent on the mass of the star. Thus at specific periods every cepheid of one type has the same luminosity. The standard candles approach can be used for supe ...
nebula - Harding University
... formation and of the presence of disk-like structures surrounding these new stars. The four massive stars that dominate this region are emitting radiation and gasses which are interacting with the smaller young stars being formed. These stellar winds may prevent the formation of possible solar sys ...
... formation and of the presence of disk-like structures surrounding these new stars. The four massive stars that dominate this region are emitting radiation and gasses which are interacting with the smaller young stars being formed. These stellar winds may prevent the formation of possible solar sys ...
THE HERTZSPRUNG-RUSSELL DIAGRAM
... The main sequence extends up to magnitudes less than 0 (corresponding to stars at least 100 times brighter than the Sun). These stars have short main-sequence lifetimes (a star 100 times brighter than the Sun would be roughly four times as massive as the Sun, and would have a main-sequence lifetime ...
... The main sequence extends up to magnitudes less than 0 (corresponding to stars at least 100 times brighter than the Sun). These stars have short main-sequence lifetimes (a star 100 times brighter than the Sun would be roughly four times as massive as the Sun, and would have a main-sequence lifetime ...
Lecture7
... Photodisintegration: By this time the central temperature is so high that heavy nuclei hit by high energy photons (gamama rays) disintegrate to He nuclei ( particles)- so, photodisintegration. Core Collapse: Fusion of light elements up to Fe releases nuclear energy. However, the reverse, from Fe to ...
... Photodisintegration: By this time the central temperature is so high that heavy nuclei hit by high energy photons (gamama rays) disintegrate to He nuclei ( particles)- so, photodisintegration. Core Collapse: Fusion of light elements up to Fe releases nuclear energy. However, the reverse, from Fe to ...
Challenging our Understanding of Stellar Structure and Evolution
... great headway, from Hipparcos results (ESA 1997; van Leeuwen 2008) to the Hubble Space Telescope (Benedict et al. 2007). Figure 1 shows an observational HRD. In the coming era, astrometric efforts like Pan-STARRS, LSST, and Gaia will measure parallaxes of millions of stars to unprecedented precision ...
... great headway, from Hipparcos results (ESA 1997; van Leeuwen 2008) to the Hubble Space Telescope (Benedict et al. 2007). Figure 1 shows an observational HRD. In the coming era, astrometric efforts like Pan-STARRS, LSST, and Gaia will measure parallaxes of millions of stars to unprecedented precision ...
Interstellar medium, birth and life of stars
... fusion begins. This process converts helium to carbon, then to oxygen. In a massive giant, helium fusion begins gradually. In a less massive giant, it begins suddenly in a process called helium flash. The age of a stellar cluster can be estimated by plotting its stars on an H-R diagram. The upper ...
... fusion begins. This process converts helium to carbon, then to oxygen. In a massive giant, helium fusion begins gradually. In a less massive giant, it begins suddenly in a process called helium flash. The age of a stellar cluster can be estimated by plotting its stars on an H-R diagram. The upper ...
Galaxies - Mike Brotherton
... Mpc = megaparsec = 1 million parsecs Gpc = gigaparsec = 1 billion parsecs Distances of Mpc or even Gpc The light we see has left the galaxy millions or billions of years ago!! “Look-back times” of millions or billions of years ...
... Mpc = megaparsec = 1 million parsecs Gpc = gigaparsec = 1 billion parsecs Distances of Mpc or even Gpc The light we see has left the galaxy millions or billions of years ago!! “Look-back times” of millions or billions of years ...
The Milky Way and other Galaxies
... Mpc = megaparsec = 1 million parsecs Gpc = gigaparsec = 1 billion parsecs Distances of Mpc or even Gpc The light we see has left the galaxy millions or billions of years ago!! “Look-back times” of millions or billions of years ...
... Mpc = megaparsec = 1 million parsecs Gpc = gigaparsec = 1 billion parsecs Distances of Mpc or even Gpc The light we see has left the galaxy millions or billions of years ago!! “Look-back times” of millions or billions of years ...
Building the Hertzsprung
... tenth as massive as our sun? A: 1 billion years = 109 years B: 10 billion years = 1010 years C: 100 billion years = 1011 years D: 1 trillion years = 1012 years ...
... tenth as massive as our sun? A: 1 billion years = 109 years B: 10 billion years = 1010 years C: 100 billion years = 1011 years D: 1 trillion years = 1012 years ...
The Milky Way
... How can we measure the mass of the Milky Way? Why do stars behind dust clouds appear red? Why is the sky blue? Why are wavelengths of light outside the visible useful in studying the Milky Way? • How is the 21 cm line of Hydrogen produced? • Describe the spiral arms of the Milky Way and what ...
... How can we measure the mass of the Milky Way? Why do stars behind dust clouds appear red? Why is the sky blue? Why are wavelengths of light outside the visible useful in studying the Milky Way? • How is the 21 cm line of Hydrogen produced? • Describe the spiral arms of the Milky Way and what ...
I Cloudy with a Chance of Making a star is no easy thing
... gas. Some grow much bigger than others, and the losers may be ejected from the cluster altogether, creating a class of stellar runts that roam the galaxy. This picture, called competitive accretion, has been championed by Ian Bonnell of the University of St. Andrews, Matthew Bate of the University o ...
... gas. Some grow much bigger than others, and the losers may be ejected from the cluster altogether, creating a class of stellar runts that roam the galaxy. This picture, called competitive accretion, has been championed by Ian Bonnell of the University of St. Andrews, Matthew Bate of the University o ...
The physics and modes of star cluster formation: observations
... hindered by the fact that open clusters are born in molecular clouds and, during their formation and early evolution, are completely embedded in molecular gas and dust. They are thus obscured from view at optical wavelengths, where the traditional astronomical techniques are most effective. Fortunat ...
... hindered by the fact that open clusters are born in molecular clouds and, during their formation and early evolution, are completely embedded in molecular gas and dust. They are thus obscured from view at optical wavelengths, where the traditional astronomical techniques are most effective. Fortunat ...
Observing Orion
... This is very difficult object and until relatively recently it was thought to be unobservable by amateurs. It requires very clear skies and usually a large scope. A Hydrogen Beta filter is also generally required, although some references suggest that an OIII or UHC filter can work. ...
... This is very difficult object and until relatively recently it was thought to be unobservable by amateurs. It requires very clear skies and usually a large scope. A Hydrogen Beta filter is also generally required, although some references suggest that an OIII or UHC filter can work. ...
Project 4: The HR diagram. Open clusters
... The Luminosity-Radius-Temperature relation tells us that the stars in these bands must therefore be larger in radius than Main Sequence stars. There are two groups of giant stars: ...
... The Luminosity-Radius-Temperature relation tells us that the stars in these bands must therefore be larger in radius than Main Sequence stars. There are two groups of giant stars: ...
Sample Exam for 3 rd Astro Exam
... 15. Where is the galactic gas layer located? A. In the galactic halo. B. In the galactic nuclear bulge C. Beyond the Sun above and below the galactic mid-plane D. Perpendicular to the galactic plane. E. In the galactic mid-plane 16. True or false: The Sun is located within the galactic gas layer of ...
... 15. Where is the galactic gas layer located? A. In the galactic halo. B. In the galactic nuclear bulge C. Beyond the Sun above and below the galactic mid-plane D. Perpendicular to the galactic plane. E. In the galactic mid-plane 16. True or false: The Sun is located within the galactic gas layer of ...
Unit 1
... Stars change very little over a human lifespan, so it is impossible to follow a single star from birth to death. We observe stars at various stages of evolution, and can piece together a description of the evolution of stars in general Computer models provide a “fast-forward” look at the evolution o ...
... Stars change very little over a human lifespan, so it is impossible to follow a single star from birth to death. We observe stars at various stages of evolution, and can piece together a description of the evolution of stars in general Computer models provide a “fast-forward” look at the evolution o ...
Star formation PowerPoint
... 19.2 The Formation of Stars Like the Sun Planetary formation has begun, but the protostar is still not in equilibrium—all heating comes from the gravitational collapse. ...
... 19.2 The Formation of Stars Like the Sun Planetary formation has begun, but the protostar is still not in equilibrium—all heating comes from the gravitational collapse. ...
Open clusters and associations in the Gaia era
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
30 Doradus - HubbleSOURCE
... Why should we care? Because most of the stars in the Universe were formed in those dots between 8 and 12 billion years ago (roughly between redshift 1.5 and 3). ...
... Why should we care? Because most of the stars in the Universe were formed in those dots between 8 and 12 billion years ago (roughly between redshift 1.5 and 3). ...
Open cluster
An open cluster, also known as galactic cluster, is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist. They are loosely bound by mutual gravitational attraction and become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center, resulting in a migration to the main body of the galaxy as well as a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.Young open clusters may still be contained within the molecular cloud from which they formed, illuminating it to create an H II region. Over time, radiation pressure from the cluster will disperse the molecular cloud. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest of the gas away.Open clusters are key objects in the study of stellar evolution. Because the cluster members are of similar age and chemical composition, their properties (such as distance, age, metallicity and extinction) are more easily determined than they are for isolated stars. A number of open clusters, such as the Pleiades, Hyades or the Alpha Persei Cluster are visible with the naked eye. Some others, such as the Double Cluster, are barely perceptible without instruments, while many more can be seen using binoculars or telescopes. The Wild Duck Cluster, M11, is an example.