A Comet-Hunter`s Legacy -
... near-collision about six hundred million years in the past; and each time they pass by each other, they undergo episodes of star formation caused by their gravitational interaction. M81's bright spiral arms are the site of star formation, partially caused by density waves raised by the most recent p ...
... near-collision about six hundred million years in the past; and each time they pass by each other, they undergo episodes of star formation caused by their gravitational interaction. M81's bright spiral arms are the site of star formation, partially caused by density waves raised by the most recent p ...
Variations in Integrated Galactic Initial Mass Functions due to
... SFR over the age of the Universe is not likely to be a good approximation. However, other studies (see e.g. Sandage (1986)) find approximately constant SFR for late-type spiral galaxies (Sd/Irr), and declining SFRs with time for earliertype galaxies (where the decline time decreases while going from ...
... SFR over the age of the Universe is not likely to be a good approximation. However, other studies (see e.g. Sandage (1986)) find approximately constant SFR for late-type spiral galaxies (Sd/Irr), and declining SFRs with time for earliertype galaxies (where the decline time decreases while going from ...
The Origin and Evolution of Dust in Galaxies
... Dust formation process around stars is affected not only by the metallicities of the parent galaxies but also by elements formed inside stars, in particular, carbon Amorphous carbon, PAHs ...
... Dust formation process around stars is affected not only by the metallicities of the parent galaxies but also by elements formed inside stars, in particular, carbon Amorphous carbon, PAHs ...
Do We Know of Any Maunder Minimum Stars?
... (Perryman et al. 1997; Perryman & ESA 1997). To increase the confidence in the results here, only those WMBV stars with more than two Keck observations are used in this work. The bulk of the ∼ 1000 stars in WMBV are currently being monitored for radial velocity variations and are typically bright, w ...
... (Perryman et al. 1997; Perryman & ESA 1997). To increase the confidence in the results here, only those WMBV stars with more than two Keck observations are used in this work. The bulk of the ∼ 1000 stars in WMBV are currently being monitored for radial velocity variations and are typically bright, w ...
Dark Matter, Dark Energy, and the Fate of the Universe
... Orbits of Galaxies in Clusters The idea of dark matter is not particularly new. In the 1930s, astronomer Fritz Zwicky was already arguing that clusters of galaxies held enormous amounts of this mysterious stuff (Figure 18.5). Few of his colleagues paid attention, but later observations supported Zw ...
... Orbits of Galaxies in Clusters The idea of dark matter is not particularly new. In the 1930s, astronomer Fritz Zwicky was already arguing that clusters of galaxies held enormous amounts of this mysterious stuff (Figure 18.5). Few of his colleagues paid attention, but later observations supported Zw ...
Wolf-Rayet Stars
... advent of faster computers with large memories, new numerical techniques, and the availability of atomic data have now made it feasible to include iron and other species in non-LTE. ...
... advent of faster computers with large memories, new numerical techniques, and the availability of atomic data have now made it feasible to include iron and other species in non-LTE. ...
MPhil Thesis - Final - Suzanne Knight
... In the past number of years, an increasing number of planets detected by transit and radial velocity surveys (Borucki et al. 2011; Mayor et al. 2011) have given credence to the quest of finding life elsewhere in the universe 1. The NASA Kepler Mission for example, was designed to use the transit met ...
... In the past number of years, an increasing number of planets detected by transit and radial velocity surveys (Borucki et al. 2011; Mayor et al. 2011) have given credence to the quest of finding life elsewhere in the universe 1. The NASA Kepler Mission for example, was designed to use the transit met ...
thick disk - asteroSTEP
... the rapid chemical evolution which took place in the inner disk before the instability acted ...
... the rapid chemical evolution which took place in the inner disk before the instability acted ...
– 1 – 1. Emission Lines in Nearby Galaxies 1.1.
... electron temperature. The strength of forbidden lines is easy to calculate since they are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in an overpopulation of the metastable states and the forbidden transitions dominate ...
... electron temperature. The strength of forbidden lines is easy to calculate since they are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in an overpopulation of the metastable states and the forbidden transitions dominate ...
Precision engineering for astronomy
... mechanics, without which the scientific and industrial revolutions of the next centuries would have been impossible. Since Tycho’s time, precision of measurement in astronomy has progressed by three orders of magnitude, with interferometers such as the European Southern Observatory’s Very Large Teles ...
... mechanics, without which the scientific and industrial revolutions of the next centuries would have been impossible. Since Tycho’s time, precision of measurement in astronomy has progressed by three orders of magnitude, with interferometers such as the European Southern Observatory’s Very Large Teles ...
Elliptical Galaxies
... found in de Zeeuw and Franx (1992). Dark haloes: mass at large radius Spiral galaxy rotation curves have been used to show that they are embedded in dark haloes that contain three to ten times as much mass as is visible in stars, gas and dust. Can dark haloes be detected in elliptical galaxies? The ...
... found in de Zeeuw and Franx (1992). Dark haloes: mass at large radius Spiral galaxy rotation curves have been used to show that they are embedded in dark haloes that contain three to ten times as much mass as is visible in stars, gas and dust. Can dark haloes be detected in elliptical galaxies? The ...
Abstract book
... is currently matter of controversy and depends very much on the own definition of cluster. The cluster definition and hence the morphologies of individual clusters appear to vary significantly from region to region, as well as with age, which suggests that either, star formation in clusters is not uni ...
... is currently matter of controversy and depends very much on the own definition of cluster. The cluster definition and hence the morphologies of individual clusters appear to vary significantly from region to region, as well as with age, which suggests that either, star formation in clusters is not uni ...
ALMA - ESO
... Detect the Milky Way at z=3 Measure dust broadband emission and spectral line radiation from atoms and molecules in high-z galaxies to obtain detailed morphology and kinematics ...
... Detect the Milky Way at z=3 Measure dust broadband emission and spectral line radiation from atoms and molecules in high-z galaxies to obtain detailed morphology and kinematics ...
FIRST STELLAR ABUNDANCES IN THE DWARF IRREGULAR
... stars, thermal pulsing in low and intermediate mass AGB stars. Thus, more elements than just those observed in nebulae need to be measured, since each have different formation sites which sample different constituents. The α elements like oxygen are created primarily in short-lived massive stars, wh ...
... stars, thermal pulsing in low and intermediate mass AGB stars. Thus, more elements than just those observed in nebulae need to be measured, since each have different formation sites which sample different constituents. The α elements like oxygen are created primarily in short-lived massive stars, wh ...
DUSTY CIRCUMSTELLAR DISKS B. Zuckerman
... range, because such stars are hard to identify with IR and optical techniques. Recently, surveys of X-ray emission, especially with the German ROSAT satellite, have enabled detection of many stars that appear to be old or post T Tauri stars (e.g., Neuhäuser 1997). Such stars have been discovered be ...
... range, because such stars are hard to identify with IR and optical techniques. Recently, surveys of X-ray emission, especially with the German ROSAT satellite, have enabled detection of many stars that appear to be old or post T Tauri stars (e.g., Neuhäuser 1997). Such stars have been discovered be ...
The Collision Between The Milky Way And Andromeda
... galaxies. Together with their ∼ 40 smaller companions, the Milky Way and Andromeda comprise our galactic neighborhood, and as such, represent the nearest laboratory, and therefore the most powerful tool, to study the formation and evolution of galactic structure. Like most extragalactic groups, the ...
... galaxies. Together with their ∼ 40 smaller companions, the Milky Way and Andromeda comprise our galactic neighborhood, and as such, represent the nearest laboratory, and therefore the most powerful tool, to study the formation and evolution of galactic structure. Like most extragalactic groups, the ...
Zapartas_deMink_Izzard_AA_2017
... Most massive stars, the progenitors of core-collapse supernovae, are in close binary systems and may interact with their companion through mass transfer or merging. We undertake a population synthesis study to compute the delay-time distribution of core-collapse supernovae, that is, the supernova ra ...
... Most massive stars, the progenitors of core-collapse supernovae, are in close binary systems and may interact with their companion through mass transfer or merging. We undertake a population synthesis study to compute the delay-time distribution of core-collapse supernovae, that is, the supernova ra ...
than a one-hit wonder. Falk, Dan Astronomy
... Army at its rocket-testing site in White Sands, New Mexico. One of his main tasks was to design ...
... Army at its rocket-testing site in White Sands, New Mexico. One of his main tasks was to design ...
The first carbon-enhanced metal-poor star found in the Sculptor
... continuum points became rarer, and a continuum could only be estimated from points close to the continuum. At the bluest part of the spectrum, the B-X band of CN at 3888 Å is extremely strong, and wipes out all continuum points making normalization in the region very uncertain, so the bluest part of ...
... continuum points became rarer, and a continuum could only be estimated from points close to the continuum. At the bluest part of the spectrum, the B-X band of CN at 3888 Å is extremely strong, and wipes out all continuum points making normalization in the region very uncertain, so the bluest part of ...
A Budget and Accounting of Metals at z~ 0: Results from the COS
... of oxygen in their ISM. COS-Halos has specifically addressed the metal content of diffuse halo gas. The current study aims to place these findings on highly ionized oxygen into the larger context of metal masses contained within all galactic and circumgalactic components: stars, dust, and the other ...
... of oxygen in their ISM. COS-Halos has specifically addressed the metal content of diffuse halo gas. The current study aims to place these findings on highly ionized oxygen into the larger context of metal masses contained within all galactic and circumgalactic components: stars, dust, and the other ...
Open clusters and associations in the Gaia era
... Another difference between a cluster and an association arising directly from their definition is the lifetime. An open cluster is loosely bound and its star members will stay together for about 100 Myr to a few Gyr for the densest ones, before it gets disrupted by the galactic tidal field. On the c ...
... Another difference between a cluster and an association arising directly from their definition is the lifetime. An open cluster is loosely bound and its star members will stay together for about 100 Myr to a few Gyr for the densest ones, before it gets disrupted by the galactic tidal field. On the c ...
Rocky planetesimals as the origin of metals in DZ stars
... evidence of pollution via circumstellar material, as yet there is none favouring the ISM. Aannestad et al. (1993) provided an extensive spatial, kinematical and calcium abundance analysis against which they tested likely scenarios of interstellar accretion based on the best available data at that ti ...
... evidence of pollution via circumstellar material, as yet there is none favouring the ISM. Aannestad et al. (1993) provided an extensive spatial, kinematical and calcium abundance analysis against which they tested likely scenarios of interstellar accretion based on the best available data at that ti ...
Direct Imaging of Exoplanets - American Museum of Natural History
... and spectra of exoplanet systems. For this information, planets around nearby stars will be essential, because these systems will have larger apparent sizes and photon fluxes than more distant systems, and will therefore be relatively accessible to the techniques in this chapter. A combination of as ...
... and spectra of exoplanet systems. For this information, planets around nearby stars will be essential, because these systems will have larger apparent sizes and photon fluxes than more distant systems, and will therefore be relatively accessible to the techniques in this chapter. A combination of as ...
Science with IMACS on Magellan
... advantage. Michael Rauch plans to use narrow-band filters to search for high-redshift galaxies through the detection of Lyα. Again, at a given redshift these systems are sufficiently rare that a large imaging field offers a crucial advantage. Alan Dressler has been measuring the distances to galaxie ...
... advantage. Michael Rauch plans to use narrow-band filters to search for high-redshift galaxies through the detection of Lyα. Again, at a given redshift these systems are sufficiently rare that a large imaging field offers a crucial advantage. Alan Dressler has been measuring the distances to galaxie ...
Space Interferometry Mission
The Space Interferometry Mission, or SIM, also known as SIM Lite (formerly known as SIM PlanetQuest), was a planned space telescope developed by the U.S. National Aeronautics and Space Administration (NASA), in conjunction with contractor Northrop Grumman. One of the main goals of the mission was the hunt for Earth-sized planets orbiting in the habitable zones of nearby stars other than the Sun. SIM was postponed several times and finally cancelled in 2010.In addition to hunting for extrasolar planets, SIM would have helped astronomers construct a map of the Milky Way galaxy. Other important tasks would have included collecting data to help pinpoint stellar masses for specific types of stars, assisting in the determination of the spatial distribution of dark matter in the Milky Way and in the Local Group of galaxies and using the gravitational microlensing effect to measure the mass of stars.The spacecraft would have used optical interferometry to accomplish these and other scientific goals. This technique collects light with multiple mirrors (in SIM's case, two) which is combined to make an interference pattern which can be very precisely measured.The initial contracts for SIM Lite were awarded in 1998, totaling US$200 million. Work on the SIM project required scientists and engineers to move through eight specific new technology milestones, and by November 2006, all eight had been completed.SIM Lite was originally scheduled for a 2005 launch, aboard an Evolved Expendable Launch Vehicle (EELV). As a result of continued budget cuts, the launch date has been pushed back at least five times. NASA has set a preliminary launch date for 2015 and U.S. federal budget documents confirm that a launch date is expected ""no earlier"" than 2015. The budget cuts to SIM Lite are expected to continue through FY 2010. As of February 2007, many of the engineers working on the SIM program had moved on to other areas and projects, and NASA directed the project to allocate its resources toward engineering risk reduction. However, the preliminary budget for NASA for 2008 included zero dollars for SIM.In December 2007, the Congress restored funding for fiscal year 2008 as part of an omnibus appropriations bill which the President later signed. At the same time the Congress directed NASA to move the mission forward to the development phase. In 2009 the project continued its risk reduction work while waiting for the findings and recommendations of the Astronomy and Astrophysics Decadal Survey, Astro2010, performed by the National Academy of Sciences, which would determine the project's future.On 13 August 2010, the Astro2010 Decadal Report was released and did not recommend that NASA continue the development of the SIM Lite Astrometric Observatory. This prompted NASA Astronomy and Physics Director, Jon Morse, to issue a letter on 24 September 2010 to the SIM Lite project manager, informing him that NASA was discontinuing its sponsorship of the SIM Lite mission and directing the project to discontinue Phase B activities immediately or as soon as practical. Accordingly, all SIM Lite activities were closed down by the end of calendar year 2010.