sections 12-15 instructor notes
... the University of Toronto, April 1979) Luminosity Functions. Every astronomer deals almost daily with luminosity functions of some sort. In a way the most basic of such functions is the general luminosity function (GLF), which gives us the distribution function of absolute magnitude, M, for the aver ...
... the University of Toronto, April 1979) Luminosity Functions. Every astronomer deals almost daily with luminosity functions of some sort. In a way the most basic of such functions is the general luminosity function (GLF), which gives us the distribution function of absolute magnitude, M, for the aver ...
star formation and galactic evolution
... sweep around these clouds, ablating their outer layers but doing relatively little damage to their denser inner regions. By contrast, ionization simply evaporates even very dense clouds, and this destroys them very effectively at a rate that is not strongly sensitive to the cloud structure or densit ...
... sweep around these clouds, ablating their outer layers but doing relatively little damage to their denser inner regions. By contrast, ionization simply evaporates even very dense clouds, and this destroys them very effectively at a rate that is not strongly sensitive to the cloud structure or densit ...
Document
... Borch et al. (Combo-17) 2006 A&A, 453, 869. “We find that the total stellar mass density of the universe has roughly doubled since z ~ 1…Intriguingly, the integrated stellar mass of blue galaxies with young stars has not significantly changed since z ~ 1…instead, the growth of the total stellar mass ...
... Borch et al. (Combo-17) 2006 A&A, 453, 869. “We find that the total stellar mass density of the universe has roughly doubled since z ~ 1…Intriguingly, the integrated stellar mass of blue galaxies with young stars has not significantly changed since z ~ 1…instead, the growth of the total stellar mass ...
Enhanced lithium depletion in Sun-like stars with orbiting planets.
... 451 stars in the HARPS high precision (better than 1 m/s) radial velocity exoplanet survey11 spanning the effective temperature range between 4900 and 6500 K. These are unevolved, slowly rotating non-active stars from a CORALIE catalogue11. These stars have been monitored with high precision spectro ...
... 451 stars in the HARPS high precision (better than 1 m/s) radial velocity exoplanet survey11 spanning the effective temperature range between 4900 and 6500 K. These are unevolved, slowly rotating non-active stars from a CORALIE catalogue11. These stars have been monitored with high precision spectro ...
Astronomy Astrophysics NGC 7419 as a template for red supergiant clusters &
... the area. We then applied standard analysis and classification techniques. Results. We find a distance of 4 ± 0.4 kpc and an age of 14 ± 2 Myr for NGC 7419. The main-sequence turn-off is found at spectral type B1, in excellent agreement. We identify 179 B-type members, implying that there are more th ...
... the area. We then applied standard analysis and classification techniques. Results. We find a distance of 4 ± 0.4 kpc and an age of 14 ± 2 Myr for NGC 7419. The main-sequence turn-off is found at spectral type B1, in excellent agreement. We identify 179 B-type members, implying that there are more th ...
Statistical analysis of stellar evolution
... simplifies statistical analysis because we expect the stars to have nearly the same metallicity, age, and distance; only their masses differ. Unfortunately, the data are contaminated with stars that are in the same line of sight as the cluster but are not part of the cluster. These stars appear to b ...
... simplifies statistical analysis because we expect the stars to have nearly the same metallicity, age, and distance; only their masses differ. Unfortunately, the data are contaminated with stars that are in the same line of sight as the cluster but are not part of the cluster. These stars appear to b ...
Evidence for a signature of the galactic bar in the solar neighbourhood
... ment of the models with the COBE/DIRBE data), u of the order of 20 km s−1 are obtained, in agreement with the observations reported in Fig. 1. Fig. 6 is a slice cutting of Fig. 5 for φ = 30◦ . The values of u have been averaged within bins of 200 Myr time width. One obtains a significantly positive ...
... ment of the models with the COBE/DIRBE data), u of the order of 20 km s−1 are obtained, in agreement with the observations reported in Fig. 1. Fig. 6 is a slice cutting of Fig. 5 for φ = 30◦ . The values of u have been averaged within bins of 200 Myr time width. One obtains a significantly positive ...
Introduction
... A galaxy is a self-gravitating system composed of an interstellar medium, stars, and dark matter. It’s difficult to overstate the role of gravity in galaxies. While the electromagnetic force has the same r 2 dependence as gravity, charge cancellation insures that large-scale electromagnetic forces a ...
... A galaxy is a self-gravitating system composed of an interstellar medium, stars, and dark matter. It’s difficult to overstate the role of gravity in galaxies. While the electromagnetic force has the same r 2 dependence as gravity, charge cancellation insures that large-scale electromagnetic forces a ...
AST1100 Lecture Notes
... Several stars show periodic changes in their apparent magnitudes. This was first thought to be caused by dark spots on a rotating star’s surface: When the dark spots were turned towards us, the star appeared fainter, when the spots were turned away from us, the star appeared brighter. Today we know ...
... Several stars show periodic changes in their apparent magnitudes. This was first thought to be caused by dark spots on a rotating star’s surface: When the dark spots were turned towards us, the star appeared fainter, when the spots were turned away from us, the star appeared brighter. Today we know ...
Galactic Archaeology: Current Surveys
... The spectra from the SDSS surveys provide line-of-sight velocities to around 10 km/s. The values of the stellar atmospheric parameters are obtained through a dedicated pipeline (Lee et al. 2008), developed for the broad range of targets and giving metallicity estimates to ∼ 0.2 dex, and for high sig ...
... The spectra from the SDSS surveys provide line-of-sight velocities to around 10 km/s. The values of the stellar atmospheric parameters are obtained through a dedicated pipeline (Lee et al. 2008), developed for the broad range of targets and giving metallicity estimates to ∼ 0.2 dex, and for high sig ...
DTU_9e_ch15
... This map, based on radio telescope surveys of 21-cm radiation, shows the distribution of hydrogen gas in a face-on view of the Galaxy. This view just hints at spiral structure. The galactic nucleus is marked with a dot surrounded by a circle. Details in the large, blank, wedge-shaped region toward t ...
... This map, based on radio telescope surveys of 21-cm radiation, shows the distribution of hydrogen gas in a face-on view of the Galaxy. This view just hints at spiral structure. The galactic nucleus is marked with a dot surrounded by a circle. Details in the large, blank, wedge-shaped region toward t ...
AST1100 Lecture Notes
... apparent and absolute magnitude. So the stars with a larger/smaller apparent magnitude also had a larger/smaller absolute magnitude. Since absolute magnitude is a measure of luminosity, what she had found was a period-luminosity relation. Pulsating stars with higher luminosity were thus found to be ...
... apparent and absolute magnitude. So the stars with a larger/smaller apparent magnitude also had a larger/smaller absolute magnitude. Since absolute magnitude is a measure of luminosity, what she had found was a period-luminosity relation. Pulsating stars with higher luminosity were thus found to be ...
AST1100 Lecture Notes
... Several stars show periodic changes in their apparent magnitudes. This was first thought to be caused by dark spots on a rotating star’s surface: When the dark spots were turned towards us, the star appeared fainter, when the spots were turned away from us, the star appeared brighter. Today we know ...
... Several stars show periodic changes in their apparent magnitudes. This was first thought to be caused by dark spots on a rotating star’s surface: When the dark spots were turned towards us, the star appeared fainter, when the spots were turned away from us, the star appeared brighter. Today we know ...
exploring anticorrelations and light element variations
... literature. Targets were selected as cluster members if (1) there is published abundance information on the star as a cluster member, (2) the star is a radial velocity member, or (3) if it has a probability >50% of being a cluster member based on their proper motion adopted from the literature. Afte ...
... literature. Targets were selected as cluster members if (1) there is published abundance information on the star as a cluster member, (2) the star is a radial velocity member, or (3) if it has a probability >50% of being a cluster member based on their proper motion adopted from the literature. Afte ...
Slide 1
... Recall that the average speed of atoms in a cloud is one and the same as the cloud’s temperature. The atoms in hotter gases travel faster. In galaxy clusters, the combined gravity of all the galaxies tends to hold the intergalactic gas within the cluster. Consider: galactic clusters will retain gas, ...
... Recall that the average speed of atoms in a cloud is one and the same as the cloud’s temperature. The atoms in hotter gases travel faster. In galaxy clusters, the combined gravity of all the galaxies tends to hold the intergalactic gas within the cluster. Consider: galactic clusters will retain gas, ...
Entropy
... because, according to the modern concepts, stars of the same cluster are formed from the same molecular cloud and therefore have the same age (which is relatively easy to determine) and the same composition (e.g., metallicity [Fe/H]). Furthermore, cluster stars are located at the same distance from ...
... because, according to the modern concepts, stars of the same cluster are formed from the same molecular cloud and therefore have the same age (which is relatively easy to determine) and the same composition (e.g., metallicity [Fe/H]). Furthermore, cluster stars are located at the same distance from ...
What are Messier Objects? - Bowling Green State University
... University Observatory with the 0.5 meter telescope. To get a quality image while taking pictures with a CCD camera a lot of things need to be considered: Visual magnitude of object Lof the object in the sky Exposure time Highest count possible with CCD camera Filters being used. The goal is to ...
... University Observatory with the 0.5 meter telescope. To get a quality image while taking pictures with a CCD camera a lot of things need to be considered: Visual magnitude of object Lof the object in the sky Exposure time Highest count possible with CCD camera Filters being used. The goal is to ...
Document
... Origin of the anomalous abundances The Ap phenomenon must be a surface phenomenon since the overabundance of rare earth elements (e.g. Eu is overabundant by a factor of up to 104 ) is so great that a signficant fraction of the supply of such elements in the Universe would be contained in Ap stars i ...
... Origin of the anomalous abundances The Ap phenomenon must be a surface phenomenon since the overabundance of rare earth elements (e.g. Eu is overabundant by a factor of up to 104 ) is so great that a signficant fraction of the supply of such elements in the Universe would be contained in Ap stars i ...
Galaxies - University of Iowa Astrophysics
... Galactic center? D) We observe dusty regions in the Galactic plane. ...
... Galactic center? D) We observe dusty regions in the Galactic plane. ...
Red supergiants around the obscured open cluster Stephenson 2
... other RSG clusters is unclear. Though all the clusters are located at a similar distance and have similar ages, they span ∼500 pc in projection. There have been suggestions that this Scutum Complex represents a giant star formation region triggered by the dynamical excitation of the Galactic Bar, wh ...
... other RSG clusters is unclear. Though all the clusters are located at a similar distance and have similar ages, they span ∼500 pc in projection. There have been suggestions that this Scutum Complex represents a giant star formation region triggered by the dynamical excitation of the Galactic Bar, wh ...
Constellation ARA
... planet 12152 Aratus are Hades, and Poseidon. When the named in his honour youngest child, Zeus, was born, his mother Rhea hid him in Crete and gave Cronus a stone to swallow, telling him the stone was Zeus. When Zeus grew up, he made Cronus vomit his brothers and sisters. Once freed, they banded tog ...
... planet 12152 Aratus are Hades, and Poseidon. When the named in his honour youngest child, Zeus, was born, his mother Rhea hid him in Crete and gave Cronus a stone to swallow, telling him the stone was Zeus. When Zeus grew up, he made Cronus vomit his brothers and sisters. Once freed, they banded tog ...
main sequence stars of a open cluster
... Then press a button ‘(3) Indentify stars, calc V & B-V’. Here, the program automatically check star data in B and V each other, within an allowance of difference in centroid position set by ‘Allowance of centroid difference’. Then it calculates magnitudes and colors. It may take some time, and the w ...
... Then press a button ‘(3) Indentify stars, calc V & B-V’. Here, the program automatically check star data in B and V each other, within an allowance of difference in centroid position set by ‘Allowance of centroid difference’. Then it calculates magnitudes and colors. It may take some time, and the w ...
Age-Dating of Young Stars and Stellar Systems
... medium (ISM) to convert stellar far-UV continuum photons into optical and IR nebular line photons is the basis of the most commonly used technique to age-date ionizing populations: recombination lines, like Hβ, are strongly agedependent (e.g., Figure 85 of Leitherer et al. 1999). There is, however, ...
... medium (ISM) to convert stellar far-UV continuum photons into optical and IR nebular line photons is the basis of the most commonly used technique to age-date ionizing populations: recombination lines, like Hβ, are strongly agedependent (e.g., Figure 85 of Leitherer et al. 1999). There is, however, ...
Local group
... which live 'forever', • massive stars inject into ISM a mass pDMtotal of heavy elements (p depends on the IMF and the yield of SN- normalized to total mass of stars). • Assumptions: galaxies gas is well mixed, no infall or outflow, high mass stars return metals to ISM faster than time to form new st ...
... which live 'forever', • massive stars inject into ISM a mass pDMtotal of heavy elements (p depends on the IMF and the yield of SN- normalized to total mass of stars). • Assumptions: galaxies gas is well mixed, no infall or outflow, high mass stars return metals to ISM faster than time to form new st ...
sections 7-8 instructor notes
... A-type stars is atomic hydrogen, which makes its presence obvious in the flux distributions of such stars with discrete discontinuities in the stellar continua at λ912Å (the Lyman discontinuity), λ3647Å (the Balmer discontinuity), and λ8206Å (the Paschen discontinuity). The primary opacity source in ...
... A-type stars is atomic hydrogen, which makes its presence obvious in the flux distributions of such stars with discrete discontinuities in the stellar continua at λ912Å (the Lyman discontinuity), λ3647Å (the Balmer discontinuity), and λ8206Å (the Paschen discontinuity). The primary opacity source in ...
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.