5 Report of the Panel on Stars and Stellar Evolution
... The science frontier for stars and stellar evolution is as close as the Sun and as distant as exploding stars at redshift 8.3. It includes understanding processes of exquisite complexity that connect the rotation of stars with their magnetic fields and areas of nearly total ignorance about phenomena ...
... The science frontier for stars and stellar evolution is as close as the Sun and as distant as exploding stars at redshift 8.3. It includes understanding processes of exquisite complexity that connect the rotation of stars with their magnetic fields and areas of nearly total ignorance about phenomena ...
Inauguration Dossier - Gran Telescopio CANARIAS
... that occur when circles are grouped together, hexagons can use space more efficiently. The GTC needs to use every inch of its primary mirror if it is to collect the maximum possible amount of light. That is why, like composite eyes in insects, the mirror is divided into hexagonal segments. When ligh ...
... that occur when circles are grouped together, hexagons can use space more efficiently. The GTC needs to use every inch of its primary mirror if it is to collect the maximum possible amount of light. That is why, like composite eyes in insects, the mirror is divided into hexagonal segments. When ligh ...
Galaxy Sorting
... galaxies contain mostly old stars, with very little gas and dust found between stars. Since new stars form from clouds of interstellar gas and dust, elliptical galaxies lack the raw ingredients to make new stars. Spiral galaxies, on the other hand, have a mix of young and old stars. Interstellar ...
... galaxies contain mostly old stars, with very little gas and dust found between stars. Since new stars form from clouds of interstellar gas and dust, elliptical galaxies lack the raw ingredients to make new stars. Spiral galaxies, on the other hand, have a mix of young and old stars. Interstellar ...
PH607lec08
... 2.4 Barred spirals A large fraction of disk galaxies have bars: narrow linear structures crossing the face of the galaxy. In barred S0 galaxies the bar is often the only structure visible in the disk. In types SBa and later the bar often connects to a spiral pattern extending to larger radii (e.g. N ...
... 2.4 Barred spirals A large fraction of disk galaxies have bars: narrow linear structures crossing the face of the galaxy. In barred S0 galaxies the bar is often the only structure visible in the disk. In types SBa and later the bar often connects to a spiral pattern extending to larger radii (e.g. N ...
A search for debris disks in the Herschel
... the largest open time key programme on the Herschel Space Observatory (Pilbratt et al. 2010), and will ultimately map over 500 square degrees with both the PACS and SPIRE instruments (Poglitsch et al. 2010; Griffin et al. 2010). H-ATLAS is designed to revolutionise our view of dust and dust-obscured s ...
... the largest open time key programme on the Herschel Space Observatory (Pilbratt et al. 2010), and will ultimately map over 500 square degrees with both the PACS and SPIRE instruments (Poglitsch et al. 2010; Griffin et al. 2010). H-ATLAS is designed to revolutionise our view of dust and dust-obscured s ...
Galaxy formation in the Planck cosmology - II. Star
... over time. The latter follows only the history of the main component of the galaxy (along the ‘main branch’ of the merger tree) and has been investigated for the Millennium Simulation by Cohn & van de Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH ...
... over time. The latter follows only the history of the main component of the galaxy (along the ‘main branch’ of the merger tree) and has been investigated for the Millennium Simulation by Cohn & van de Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH ...
A New Science Strategy for Space Astronomy and Astrophysics
... NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee ...
... NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee ...
Galaxies
... e. the stars in the spiral arms emit most of their energy at radio wavelengths. If the spiral density wave were the only thing producing spiral arms, it would be expected that a. all spiral arms would be dust free. b. all galaxies would have only two smooth spiral arms. c. the Milky Way would be mor ...
... e. the stars in the spiral arms emit most of their energy at radio wavelengths. If the spiral density wave were the only thing producing spiral arms, it would be expected that a. all spiral arms would be dust free. b. all galaxies would have only two smooth spiral arms. c. the Milky Way would be mor ...
Measuring the Stars Section 29.2
... Red giants are large, cool, luminous stars. They are so large—more than 100 times the size of the Sun in some cases—that Earth would be swallowed up if the Sun were to become a red giant. ...
... Red giants are large, cool, luminous stars. They are so large—more than 100 times the size of the Sun in some cases—that Earth would be swallowed up if the Sun were to become a red giant. ...
- ANU Repository
... that can be compared with those around solar-type stars to test models of planet formation (e.g. Gaidos & Mann 2014). There have been several recent works estimating the occurrence of planets around M dwarfs, the distribution with radii, and the number of planets within a ‘habitable zone’ (HZ) bound ...
... that can be compared with those around solar-type stars to test models of planet formation (e.g. Gaidos & Mann 2014). There have been several recent works estimating the occurrence of planets around M dwarfs, the distribution with radii, and the number of planets within a ‘habitable zone’ (HZ) bound ...
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 ...
Ch. 20 - Astro1010
... 3rd law. We take the radius of our orbit and the period. Plugging those numbers into Kepler's 3rd law we can estimate the mass inside our orbit. This gives just shy of 100 billion solar masses. Other mass estimates of the Milky Way are up to 1 trillion solar masses. ...
... 3rd law. We take the radius of our orbit and the period. Plugging those numbers into Kepler's 3rd law we can estimate the mass inside our orbit. This gives just shy of 100 billion solar masses. Other mass estimates of the Milky Way are up to 1 trillion solar masses. ...
White dwarf cooling sequences and cosmochronology
... remaining quantities, the initial mass function, (M), and the star formation rate, (t), are not known a priori and depend on the astronomical properties of the stellar population under study. Since the total density of white dwarfs of a given population is not usually well known, to compare the th ...
... remaining quantities, the initial mass function, (M), and the star formation rate, (t), are not known a priori and depend on the astronomical properties of the stellar population under study. Since the total density of white dwarfs of a given population is not usually well known, to compare the th ...
Wandering in the Redshift Desert
... COSMOS pBzKs (and along with them a much larger number of star-forming galaxies in the desert) would take about a quarter of the time we have estimated above for FORS2, i.e., some 350 VLT nights. This still looks like a lot of time, yet is somewhat more affordable than a mere FORS2 brute force effor ...
... COSMOS pBzKs (and along with them a much larger number of star-forming galaxies in the desert) would take about a quarter of the time we have estimated above for FORS2, i.e., some 350 VLT nights. This still looks like a lot of time, yet is somewhat more affordable than a mere FORS2 brute force effor ...
On the nature and detectability of Type Ib/c supernova progenitors
... tor masses. The caveat here is that Meynet et al. (1994) applied a correction to the radii of their WR star models to take into account the radial extension of the star due to an optically thick wind, following Langer (1989) and Maeder (1990). This correction is particularly large as they employed h ...
... tor masses. The caveat here is that Meynet et al. (1994) applied a correction to the radii of their WR star models to take into account the radial extension of the star due to an optically thick wind, following Langer (1989) and Maeder (1990). This correction is particularly large as they employed h ...
Is there a Supermassive Black Hole at the Center of the Milky Way?
... parsecs, the system would be dynamically unstable with less massive stars being expelled (“evaporated”) and more massive stars sinking to the center, colliding and possibly forming a black hole. The timescale for the cluster to evaporate would be fairly short, ∼ 109 years, making it unlikely that a ...
... parsecs, the system would be dynamically unstable with less massive stars being expelled (“evaporated”) and more massive stars sinking to the center, colliding and possibly forming a black hole. The timescale for the cluster to evaporate would be fairly short, ∼ 109 years, making it unlikely that a ...
Behaviour of elements from lithium to europium in stars with and
... Our group has investigated nearly 600 stars, dwarfs and giants, over several years. We determined their atmospheric parameters and chemical composition in order to study the chemical and dynamical evolution of the Galaxy and, primarily, the chemical enrichment of various Galactic substructures (Mish ...
... Our group has investigated nearly 600 stars, dwarfs and giants, over several years. We determined their atmospheric parameters and chemical composition in order to study the chemical and dynamical evolution of the Galaxy and, primarily, the chemical enrichment of various Galactic substructures (Mish ...
arXiv:astro-ph/0508448v1 22 Aug 2005
... over 50% of massive runaways have enhanced surface He abundances and high rotational velocities, suggesting that their parent systems experienced mass transfer and therefore are good candidates for supernova separation. It should be noted that rapid rotation and enhanced abundances are not in themse ...
... over 50% of massive runaways have enhanced surface He abundances and high rotational velocities, suggesting that their parent systems experienced mass transfer and therefore are good candidates for supernova separation. It should be noted that rapid rotation and enhanced abundances are not in themse ...
Planet formation around stars of various masses: The snow line and
... evolution of accretion and the central star to investigate how gas giant frequency changes with stellar mass. The snow line distance changes weakly with stellar mass; thus giant planets form over a wide range of spectral types. The probability that a given star has at least one gas giant increases l ...
... evolution of accretion and the central star to investigate how gas giant frequency changes with stellar mass. The snow line distance changes weakly with stellar mass; thus giant planets form over a wide range of spectral types. The probability that a given star has at least one gas giant increases l ...
The cosmological significance of high
... We have used new and archival infrared and radio observations to search for a dwarf galaxy associated with the high-velocity cloud (HVC) known as Complex H. Complex H is a large (Ω & 400 deg2 ) and probably nearby (d = 27 kpc) HVC whose location in the Galactic plane has hampered previous investigat ...
... We have used new and archival infrared and radio observations to search for a dwarf galaxy associated with the high-velocity cloud (HVC) known as Complex H. Complex H is a large (Ω & 400 deg2 ) and probably nearby (d = 27 kpc) HVC whose location in the Galactic plane has hampered previous investigat ...
Problem Statement
... Sometime after launch on 4/24/1990, engineers testing images from the Hubble Space Telescope (HST) noticed that the images were blurry. They were unable to focus the image through normal equipment adjustments. The blurry images were determined through testing to be a form of spherical aberration. Sp ...
... Sometime after launch on 4/24/1990, engineers testing images from the Hubble Space Telescope (HST) noticed that the images were blurry. They were unable to focus the image through normal equipment adjustments. The blurry images were determined through testing to be a form of spherical aberration. Sp ...
Stellar Properties
... • a star could be very bright because is was very close to us; not because it was truly bright • two stars in the same constellation might not be close to each other; one could be much farther away ...
... • a star could be very bright because is was very close to us; not because it was truly bright • two stars in the same constellation might not be close to each other; one could be much farther away ...
Plotting Variable Stars on the H
... the H-R diagram above the Mira variables and are generally spectral class K, M, C or S. Since stars are plotted on the H-R diagram by absolute magnitude and/or luminosity and surface temperature (stellar classification), each star is plotted as one data point. Main sequence stars, giants and supergi ...
... the H-R diagram above the Mira variables and are generally spectral class K, M, C or S. Since stars are plotted on the H-R diagram by absolute magnitude and/or luminosity and surface temperature (stellar classification), each star is plotted as one data point. Main sequence stars, giants and supergi ...
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.