Star Formation in Our Galaxy - Wiley-VCH
... Figure 1.1 A portion of the Northern sky. The Milky Way is depicted as light grey, while the darker patches indicate giant molecular clouds. Also shown, according to their relative brightness, are the more prominent stars, along with principle constellations. ...
... Figure 1.1 A portion of the Northern sky. The Milky Way is depicted as light grey, while the darker patches indicate giant molecular clouds. Also shown, according to their relative brightness, are the more prominent stars, along with principle constellations. ...
11-Massive Stars
... to understand the complex bipolar outflows in massive star formation and proof will require interferometer observations. The outflows are difficult to study because multiple outflows often emanate from the same large scale core. Clusters of stars form simultaneously in a core and the outflows origin ...
... to understand the complex bipolar outflows in massive star formation and proof will require interferometer observations. The outflows are difficult to study because multiple outflows often emanate from the same large scale core. Clusters of stars form simultaneously in a core and the outflows origin ...
Entropy Production of Main-Sequence Stars
... the same distance from the Sun; (4) the HR diagram of clusters must be well approximated by theoretical isochrones plotted according to the model (the Padova database of evolutionary tracks and isochrones web-site: http://pleiadi.oapd.inaf.it/) [29,30] using the values of age and metallicity from th ...
... the same distance from the Sun; (4) the HR diagram of clusters must be well approximated by theoretical isochrones plotted according to the model (the Padova database of evolutionary tracks and isochrones web-site: http://pleiadi.oapd.inaf.it/) [29,30] using the values of age and metallicity from th ...
The Milky Way thin disk structure as revealed by stars and young
... Figure 4. Spatial distribution of open clusters in the plane of the Milky Way as a function of their age. From Dias & Lepine (2005). to the third Galactic quadrant (180o l 270o ). In this sector of the Milky Way extinction is small (Moitinho 2001), and star clusters can be detected to very dista ...
... Figure 4. Spatial distribution of open clusters in the plane of the Milky Way as a function of their age. From Dias & Lepine (2005). to the third Galactic quadrant (180o l 270o ). In this sector of the Milky Way extinction is small (Moitinho 2001), and star clusters can be detected to very dista ...
The Origin, Structure, and Evolution of the Stars
... that are about 100 times brighter than the sun lying above and to the right of the main sequence A few stars are found in the supergiant region at the upper edge of the diagram and another group of white and yellow stars hundreds of times less luminous than the sun called white dwarfs is found in th ...
... that are about 100 times brighter than the sun lying above and to the right of the main sequence A few stars are found in the supergiant region at the upper edge of the diagram and another group of white and yellow stars hundreds of times less luminous than the sun called white dwarfs is found in th ...
Lecture 6: Multiple stars
... A typical cluster has 102 – 104 stars pc3 (compared to <1 for the field) meaning that encounters are at least 102 – 104 more frequent as the collision time goes as (see also later, r is the radius of a star or stellar system): or stellar system ...
... A typical cluster has 102 – 104 stars pc3 (compared to <1 for the field) meaning that encounters are at least 102 – 104 more frequent as the collision time goes as (see also later, r is the radius of a star or stellar system): or stellar system ...
Spatial distribution of stars in the Milky Way
... Spatial distribution of stars in the Milky Way • We use a statistical approach to determine and describe the spatial distribution of stars in the Galaxy • This approach allows us to derive the structure of the disk and spheroidal components (density distribution and extent). • This information can ...
... Spatial distribution of stars in the Milky Way • We use a statistical approach to determine and describe the spatial distribution of stars in the Galaxy • This approach allows us to derive the structure of the disk and spheroidal components (density distribution and extent). • This information can ...
Galaxy Structure
... entire Galactic plane and specific nearby clouds to produce a panorama of the entire Milky Way in molecular gas at an angular resolution of Jº. Their compilation exhibits a sky coverage and resolution which are comparable with those of early 21 cm surveys. A comparison with other population I tracer ...
... entire Galactic plane and specific nearby clouds to produce a panorama of the entire Milky Way in molecular gas at an angular resolution of Jº. Their compilation exhibits a sky coverage and resolution which are comparable with those of early 21 cm surveys. A comparison with other population I tracer ...
Astrophysics Questions (DRAFT)
... 33. Describe the spectral classi cation scheme for stars: O,B,A,F,G,K,M. What are the characteristic e ective temperatures of stars of each class? What are the characteristic luminosities for main-sequence stars of each class? 34. From a physics perspective, how does the quantity (B-V) help to deter ...
... 33. Describe the spectral classi cation scheme for stars: O,B,A,F,G,K,M. What are the characteristic e ective temperatures of stars of each class? What are the characteristic luminosities for main-sequence stars of each class? 34. From a physics perspective, how does the quantity (B-V) help to deter ...
... 3. THE RR LYRAE STARS IN M15 In Clement’s (2002) data base of variables stars, a total of 158 variable stars are known, from which approximately 104 are RR Lyrae type stars. In this work, 33 known RR Lyrae stars, identified in Figs. 1 and 2 and listed in Table 4, have been studied. For all the stars ...
The Milky Way Galaxy
... Evidence #3 - The intracluster gas is too hot to be retained by the gravity of the visible matter in a cluster. If all the mass there really were only that of visible matter, its gravity would not be enough to retain the hot gas, which would evaporate rapidly. Since the gas is there, there must be m ...
... Evidence #3 - The intracluster gas is too hot to be retained by the gravity of the visible matter in a cluster. If all the mass there really were only that of visible matter, its gravity would not be enough to retain the hot gas, which would evaporate rapidly. Since the gas is there, there must be m ...
Sternentstehung - Star Formation
... - Massive stars are very important for energy budget and nucleosynthesis. - They form exclusively in a clustered mode. - They have very short Kelvin-Helmholtz contraction times and hence no optically observable pre-main sequence evolution. - Large radiation pressure has to be overcome. - Two main pr ...
... - Massive stars are very important for energy budget and nucleosynthesis. - They form exclusively in a clustered mode. - They have very short Kelvin-Helmholtz contraction times and hence no optically observable pre-main sequence evolution. - Large radiation pressure has to be overcome. - Two main pr ...
Chapter 20. Galaxies
... reflects variations in the accretion rate. The time scale for the variations can be as short as minutes, hours, days or months. When variable galaxies on these time scales were first discovered it was hard for people to believe, since no object bigger than a few light minutes could vary on time scal ...
... reflects variations in the accretion rate. The time scale for the variations can be as short as minutes, hours, days or months. When variable galaxies on these time scales were first discovered it was hard for people to believe, since no object bigger than a few light minutes could vary on time scal ...
Chapter 16 - Astronomy
... 1. The Galaxy began as a tremendous cloud of gas and dust bigger than the present Galactic halo. Mutual gravitation between the cloud’s parts pulled it together. 2. The center portion was the first to become dense enough for stars to form. Dense pockets in orbit around the center became globular clu ...
... 1. The Galaxy began as a tremendous cloud of gas and dust bigger than the present Galactic halo. Mutual gravitation between the cloud’s parts pulled it together. 2. The center portion was the first to become dense enough for stars to form. Dense pockets in orbit around the center became globular clu ...
![Module 4.1 - The Scale of the Universe [slide 1] We now turn to](http://s1.studyres.com/store/data/002846843_1-9e0ec9d1a2abbbab3c0d406694bfc4e2-300x300.png)
Module 4.1 - The Scale of the Universe [slide 1] We now turn to
... So, once we calibrate the main sequence of this Hipparcos diagram, if we can measure stellar colors or temperatures, then we can read off their absolute magnitudes. From absolute and apparent magnitudes, we can figure out how far they are. In a given cluster you may have thousands of stars, and ther ...
... So, once we calibrate the main sequence of this Hipparcos diagram, if we can measure stellar colors or temperatures, then we can read off their absolute magnitudes. From absolute and apparent magnitudes, we can figure out how far they are. In a given cluster you may have thousands of stars, and ther ...
The Origin, Structure, and Evolution of the Stars
... the evolutionary tracks of stars off the main-sequence and also gives the time spent as main-sequence stars for stars in different regions of the H-R diagram. Our calculations indicate that the more massive stars “burn” their fuel so rapidly they cannot last very long. Some of these bright stars mus ...
... the evolutionary tracks of stars off the main-sequence and also gives the time spent as main-sequence stars for stars in different regions of the H-R diagram. Our calculations indicate that the more massive stars “burn” their fuel so rapidly they cannot last very long. Some of these bright stars mus ...
August 2014 Saguaro Skies
... Aquarius. First is Sagitta and an open cluster that probably isn’t on many observing lists. It is Harvard 20 and since it isn’t that well known here are the coordinates RA 19 53.1 Dec +18 21. It is in a rich Milky Way field and doesn’t stand out well so a finder chart would be helpful. Next is the g ...
... Aquarius. First is Sagitta and an open cluster that probably isn’t on many observing lists. It is Harvard 20 and since it isn’t that well known here are the coordinates RA 19 53.1 Dec +18 21. It is in a rich Milky Way field and doesn’t stand out well so a finder chart would be helpful. Next is the g ...
Star Formation in the Rosette Complex
... The pioneering observations by Gosachinskii & Khersonskii (1982) of the HI emission at 21 cm made with the RATAN-600 telescope revealed that the Rosette Complex and the Monoceros Loop were enclosed in a thin HI envelope 130 pc in diameter, possibly expanding at 20 km·s−1 , suggesting that the supern ...
... The pioneering observations by Gosachinskii & Khersonskii (1982) of the HI emission at 21 cm made with the RATAN-600 telescope revealed that the Rosette Complex and the Monoceros Loop were enclosed in a thin HI envelope 130 pc in diameter, possibly expanding at 20 km·s−1 , suggesting that the supern ...
Dark Matter In The 21st Century
... 2) Coma cluster is not in equilibrium are needed to see this picture. (galaxies are in the process of flying apart) ...
... 2) Coma cluster is not in equilibrium are needed to see this picture. (galaxies are in the process of flying apart) ...
December - Rose City Astronomers
... two stars involved in its halo. At higher power 4319 showed its central bar with hints of two spiral arms coming off each end, with the northern arm the most prominent – at least in the peculiar way that faint objects can be considered prominent through a telescope. When making my sketch I didn’t kn ...
... two stars involved in its halo. At higher power 4319 showed its central bar with hints of two spiral arms coming off each end, with the northern arm the most prominent – at least in the peculiar way that faint objects can be considered prominent through a telescope. When making my sketch I didn’t kn ...
The self-enrichment of galactic halo globular clusters: a clue to their
... and the kinetic energy fraction interacting with the ISM must be reconsidered. While Brown et al. (1991, 1995) have mostly focused on the computations of the supershell behaviour through hydrodynamical computations, we revisit some of the ideas that have been used against the hypothesis of GC selfen ...
... and the kinetic energy fraction interacting with the ISM must be reconsidered. While Brown et al. (1991, 1995) have mostly focused on the computations of the supershell behaviour through hydrodynamical computations, we revisit some of the ideas that have been used against the hypothesis of GC selfen ...
Chemical Evolution
... 2005 eq 4; from numerical models) ; (clearly does not work if [α/Fe] >0.2) The larger∆t is the lower is the [α/Fe] ratio due to the late time enrichment of Fe due to SNIa; ∆t =10Gyrs gives solar abundance ...
... 2005 eq 4; from numerical models) ; (clearly does not work if [α/Fe] >0.2) The larger∆t is the lower is the [α/Fe] ratio due to the late time enrichment of Fe due to SNIa; ∆t =10Gyrs gives solar abundance ...
Chapter 7: The Galaxy, structure and content File
... One reason that these parameters are useful is that A vanishes for solid body rotation (i.e. A = 0 when the angular velocity Ω(R) = hvφ i/R = constant). Another useful property is that the gradient of the rotational velocity is ∂hvφ i/∂R = −(A + B) at R = R0 , which means that A + B = 0 if the rotat ...
... One reason that these parameters are useful is that A vanishes for solid body rotation (i.e. A = 0 when the angular velocity Ω(R) = hvφ i/R = constant). Another useful property is that the gradient of the rotational velocity is ∂hvφ i/∂R = −(A + B) at R = R0 , which means that A + B = 0 if the rotat ...
Feedback - Cambridge University Press
... Inventories of both stars and gas suggest that the most massive clusters contain most if not all of their cosmic abundance of baryons, i.e., fb ≈ fb,cos (Leauthaud et al. 2012, Dai et al. 2010). Lower mass halos appear to have fb < fb,cos , with fb dropping to 0.1 or smaller for halos with Mh < 1011 ...
... Inventories of both stars and gas suggest that the most massive clusters contain most if not all of their cosmic abundance of baryons, i.e., fb ≈ fb,cos (Leauthaud et al. 2012, Dai et al. 2010). Lower mass halos appear to have fb < fb,cos , with fb dropping to 0.1 or smaller for halos with Mh < 1011 ...
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.