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Дата изменения: Thu Dec 11 17:51:17 2008 Дата индексирования: Wed Jan 14 14:23:01 2009 Кодировка: Поисковые слова: universe |
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Program Number | Principal Investigator | Program Title | Links |
11103 | Harald Ebeling, University of Hawaii | A Snapshot Survey of The Most Massive Clusters of Galaxies | Abstract |
11110 | Stephan McCandliss, The Johns Hopkins University | Searching for Lyman alpha Emission from FUSE Lyman Continuum Candidates | Abstract |
11130 | Luis Ho, Carnegie Institution of Washington | AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II | Abstract |
11213 | Gerard T. van Belle, California Institute of Technology | Distances to Eclipsing M Dwarf Binaries | Abstract |
11289 | Jean-Paul Kneib, Laboratoire d'Astronomie Spatiale | SL2S: The Strong Lensing Legacy Survey | Abstract |
11704 | Brian Chaboyer, Dartmouth College | The Ages of Globular Clusters and the Population II Distance Scale | Abstract |
11942 | George Fritz Benedict, University of Texas at Austin | Increasing the Accuracy of HST Astrometry with FGS1r | Abstract |
11943 | Douglas R. Gies, Georgia State University Research Foundation | Binaries at the Extremes of the H-R Diagram | Abstract |
11945 | Asteroseismology of Extrasolar Planet Host Stars | Ron Gilliland, Space Telescope Science Institute | Abstract |
11962 | Adam Riess, The Johns Hopkins University | A New Supernova in the Antennae; Narrowing in on the Hubble Constant and Dark Energy | Abstract |
GO 11110: Searching for Lyman alpha Emission from FUSE Lyman Continuum Candidates
GO 11704: The Ages of Globular Clusters and the Population II Distance Scale
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Globular clusters are the oldest structures within the Milky Way that are directly accessible to observation. They are relatively simple systems, with relatively simple colour-magnitude diagrams (albeit with some complexities adduced from recent HST observations, see GO 11233 ). Matching those CMDs against theoretical models allows us to set constraints on the age of the oldest stars in the Galaxy, and hence on the age of the Milky Way and the epoch of galaxy formation. However, the accuracy of those age determinations rest crucially on the accuracy of the cluster distance determinations. The clusters themselves lie at distances of several kpc at best, and tens of kpc at worst; thus, direct trigonometric parallax measurements must await microacrsecond astrometric missions. The classical method of deriving distances is main sequence fitting - using nearby stars, with similar chemical abundances and accurate parallax measurements, to map out the main sequence in absolute units, and then scaling the clusetr data to fit. The problem with this method is that metal-poor subdwarfs are rare, so even Hipparcos was only able to obtain accurate distances to a handful of stars. The present program aims to improve the distance measurements by using the Fine Guidance Sensors on HST to determine sub-millarcsecond trigonometric parallaxes to 9 subdwarfs, almost doubling the sample available for MS fitting. |
GO 11945: Asteroseismology of Extrasolar Planet Host Stars