Li-cai Deng
... The Future of Galactic structure In the Milky Way, we have the opportunity to learn the whole history of one galaxy instead of comparing snapshots of many. It is only now that we have large surveys of the whole sky that we are able to comprehend the Milky Way as a whole. Unlike external galaxies, t ...
... The Future of Galactic structure In the Milky Way, we have the opportunity to learn the whole history of one galaxy instead of comparing snapshots of many. It is only now that we have large surveys of the whole sky that we are able to comprehend the Milky Way as a whole. Unlike external galaxies, t ...
EvoluGon of high mass stars Solar-‐type stars end their lives by
... These are stars composed almost en=rely of neutrons, with radii ≈ 10 km, leh over aher a core-‐collapse supernova. They are supported against gravita=onal collapse by neutron degeneracy pressure. Their ...
... These are stars composed almost en=rely of neutrons, with radii ≈ 10 km, leh over aher a core-‐collapse supernova. They are supported against gravita=onal collapse by neutron degeneracy pressure. Their ...
Astronomy 112: The Physics of Stars Class 19 Notes: The Stellar
... main sequence. Thus the majority of the stars in a cluster are always on the main sequence, even for the oldest clusters. This is because the most common stars are those with low masses, which have not yet had time to leave the main sequence. ...
... main sequence. Thus the majority of the stars in a cluster are always on the main sequence, even for the oldest clusters. This is because the most common stars are those with low masses, which have not yet had time to leave the main sequence. ...
File
... • due on-going star formation, ages of stars widely range from age of galaxy to new • spiral arms form as sustained density waves; where majority of star formation occurs ...
... • due on-going star formation, ages of stars widely range from age of galaxy to new • spiral arms form as sustained density waves; where majority of star formation occurs ...
33-3 - Fremont Peak Observatory
... viewed this object a few years back, I had to get in the general neighborhood with my eyepiece, and my mount’s clutch pins loose. I scanned the area until I saw a faint, hazy cloud which contrasts to the black background of the night sky. That “hazy cloud” turns into rings of color once the camera h ...
... viewed this object a few years back, I had to get in the general neighborhood with my eyepiece, and my mount’s clutch pins loose. I scanned the area until I saw a faint, hazy cloud which contrasts to the black background of the night sky. That “hazy cloud” turns into rings of color once the camera h ...
15-3 Notes: Galaxies
... of sizes and shapes. The largest galaxies contain more than a trillion stars. Astronomers classify a galaxy as a spiral, elliptical, or irregular galaxy according to its shape. Spiral galaxies, such as the Andromeda galaxy, have a bulge at the center and spiral arms. The spiral arms are made up of g ...
... of sizes and shapes. The largest galaxies contain more than a trillion stars. Astronomers classify a galaxy as a spiral, elliptical, or irregular galaxy according to its shape. Spiral galaxies, such as the Andromeda galaxy, have a bulge at the center and spiral arms. The spiral arms are made up of g ...
Milky Way Bulge
... • Field stars = high velocity stars • ~150 globular clusters known, in 2 different systems: • Older (~13 Gyr) • -2.5 < [Fe/H] < -0.8 • Spherical distribution around galactic center • No net rotation ...
... • Field stars = high velocity stars • ~150 globular clusters known, in 2 different systems: • Older (~13 Gyr) • -2.5 < [Fe/H] < -0.8 • Spherical distribution around galactic center • No net rotation ...
Stellar Populations of Galaxies- 2 Lectures H
... There is a severe technical issue- it is only in the MW, MW globular clusters and the Magellanic clouds that one can measure individual star over a large mass range. All other estimates of the IMF depend on integrated properties and thus are more model dependent – there is also a fundamental problem ...
... There is a severe technical issue- it is only in the MW, MW globular clusters and the Magellanic clouds that one can measure individual star over a large mass range. All other estimates of the IMF depend on integrated properties and thus are more model dependent – there is also a fundamental problem ...
– 1 – 1. Cosmochronology
... rate. Thus the distribution with luminosity of a population of white dwarfs such as is found in old globular clusters can be interpreted to yield an age for the system. In particular the detecting the termination at the faint end of the white dwarf sequence is crucial. The theory to treat this is so ...
... rate. Thus the distribution with luminosity of a population of white dwarfs such as is found in old globular clusters can be interpreted to yield an age for the system. In particular the detecting the termination at the faint end of the white dwarf sequence is crucial. The theory to treat this is so ...
Early stages of clustered star formation -massive dark clouds
... prominently visible throughout the Galaxy. In contrast to the previous phases, HII regions are not in equilibrium but continuously fed by stellar activity. The final phase comprises the cold molecular gas (n ≥ 200 cm−3 , T ∼ 10 K) that is confined to giant molecular clouds. The clouds are held toget ...
... prominently visible throughout the Galaxy. In contrast to the previous phases, HII regions are not in equilibrium but continuously fed by stellar activity. The final phase comprises the cold molecular gas (n ≥ 200 cm−3 , T ∼ 10 K) that is confined to giant molecular clouds. The clouds are held toget ...
Transcript - Chandra X
... generation (Population II) of stars has a higher metallicity – which is still less than one percent. All stars are ~75% hydrogen, ~ 24% helium, and ~1% metals. There are more than 150 globulars in the MWG. There is less gas, and the older stars are towards the center with younger stars gravitating ...
... generation (Population II) of stars has a higher metallicity – which is still less than one percent. All stars are ~75% hydrogen, ~ 24% helium, and ~1% metals. There are more than 150 globulars in the MWG. There is less gas, and the older stars are towards the center with younger stars gravitating ...
Lecture 15 Star Formation and Evolution 3/7
... • A heavier WD will have smaller radius • if Mass(WD) > 1.4 M(Sun) degenerate electrons can not resist gravity called Chandrasekhar limit and no WD has a mass greater than this • If WD can acquire mass from companion star and goes over this limit Supernova and (usually) a Neutron Star ...
... • A heavier WD will have smaller radius • if Mass(WD) > 1.4 M(Sun) degenerate electrons can not resist gravity called Chandrasekhar limit and no WD has a mass greater than this • If WD can acquire mass from companion star and goes over this limit Supernova and (usually) a Neutron Star ...
ATA2010
... If we see stars which are rich in -elements relative to iron, this means that the chemical evolution of the gas from which they formed happened quickly (~ 108 yr), before there was time for the SNIa to generate a lot of iron etc To measure the abundances of chemical elements accurately, we need hig ...
... If we see stars which are rich in -elements relative to iron, this means that the chemical evolution of the gas from which they formed happened quickly (~ 108 yr), before there was time for the SNIa to generate a lot of iron etc To measure the abundances of chemical elements accurately, we need hig ...
Lecture Notes
... ‘Regular’ clusters appear to be populated mainly by elliptical galaxies, while ‘irregular’ clusters tend to include all galaxy types. Both often have a giant elliptical galaxy (a so-called cD galaxy), ∼200 kpc in diameter, at the centre of the gravitational well. It is thought that the large number ...
... ‘Regular’ clusters appear to be populated mainly by elliptical galaxies, while ‘irregular’ clusters tend to include all galaxy types. Both often have a giant elliptical galaxy (a so-called cD galaxy), ∼200 kpc in diameter, at the centre of the gravitational well. It is thought that the large number ...
WAS THE SUN BORN IN A MASSIVE CLUSTER?
... A number of authors have argued that the Sun must have been born in a cluster of no more than several thousand stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer solar system or excited the outer planets into eccentric orbit ...
... A number of authors have argued that the Sun must have been born in a cluster of no more than several thousand stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer solar system or excited the outer planets into eccentric orbit ...
Slide 1
... astronomers to believe that our bulge is shaped like a bar. spiral arms: the arms are full of young population I stars and star forming dust clouds. ...
... astronomers to believe that our bulge is shaped like a bar. spiral arms: the arms are full of young population I stars and star forming dust clouds. ...
Autumn Asterisms for binoculars 2013
... (the Giraffe) is not one of the brightest constellations, but the Cascade is one of its showpiece objects, with the open cluster NGC 1502 to its end. It is an easy object in binoculars and a favourite of mine. You can find it by taking a line from Capella in ...
... (the Giraffe) is not one of the brightest constellations, but the Cascade is one of its showpiece objects, with the open cluster NGC 1502 to its end. It is an easy object in binoculars and a favourite of mine. You can find it by taking a line from Capella in ...
A Hero`s Little Horse: Discovery of a Dissolving Star Cluster in
... centre of mass calculated in terms of the normalised signals on the array into which the stars were binned and smoothed as described in Section 2. We derive an ellipticity = 0.42 ± 0.10 and a position angle θ = −59 ± 6 deg by using the fit bivariate normal function of the astroML package (VanderPl ...
... centre of mass calculated in terms of the normalised signals on the array into which the stars were binned and smoothed as described in Section 2. We derive an ellipticity = 0.42 ± 0.10 and a position angle θ = −59 ± 6 deg by using the fit bivariate normal function of the astroML package (VanderPl ...
Supermassive Black Holes in Inactive Galaxies Encyclopedia of Astronomy & Astrophysics eaa.iop.org
... hierarchical structure formation and galaxy mergers (see GALAXIES: INTERACTIONS AND MERGERS). If most large galaxies contain BHs, then mergers produce binary BHs and, in three-body encounters, BH ejections with recoil. How much offset we see, and indeed whether we see two BHs or one or none at all, ...
... hierarchical structure formation and galaxy mergers (see GALAXIES: INTERACTIONS AND MERGERS). If most large galaxies contain BHs, then mergers produce binary BHs and, in three-body encounters, BH ejections with recoil. How much offset we see, and indeed whether we see two BHs or one or none at all, ...
PH607 – Galaxies
... is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the l ...
... is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the l ...
ph507-16-4form
... Stage 4. The high thermal pressure resists gravity and this ends the first collapse, forming what is traditionally called the first core at a density of 1013cm-3 - 1014cm-3 and temperature of 100-200K. Stage 5. A shock wave forms at the outer edge of the first core. The first core accretes from the ...
... Stage 4. The high thermal pressure resists gravity and this ends the first collapse, forming what is traditionally called the first core at a density of 1013cm-3 - 1014cm-3 and temperature of 100-200K. Stage 5. A shock wave forms at the outer edge of the first core. The first core accretes from the ...
the magellanic clouds newsletter - Keele University Astrophysics
... present OGLE light curves of all the confirmed symbiotic stars in the Large Magellanic Cloud, with one exception. By careful visual inspection and combined time-series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects ...
... present OGLE light curves of all the confirmed symbiotic stars in the Large Magellanic Cloud, with one exception. By careful visual inspection and combined time-series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects ...
Twitter Feed ITSO Symposium 2017
... relation is unchanged, indicating that the amount of size growth from z=1 to the present day is constant with stellar mass: galaxies in massive clusters grow via minor mergers and/or adiabatic expansion, rather than by major mergers. ...
... relation is unchanged, indicating that the amount of size growth from z=1 to the present day is constant with stellar mass: galaxies in massive clusters grow via minor mergers and/or adiabatic expansion, rather than by major mergers. ...
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.