White Dwarfs in Globular Clusters:Hubble Space TelescopeObservations of M4
| Autor: | Howard E. Bond, Rodrigo A. Ibata, Carlton Pryor, William E. Harris, Peter B. Stetson, N.C. Ivanans, Michael Bolte, Harvey B. Richer, James E. Hesser, Georgi Mandushev, Steve Holland, Gregory G. Fahlman, Matt A. Wood, Roger A. Bell |
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| Rok vydání: | 1997 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Red dwarf Age of the universe Astrophysics::High Energy Astrophysical Phenomena White dwarf Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Stars Space and Planetary Science Globular cluster 0103 physical sciences Cluster (physics) Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Stellar evolution Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Luminosity function (astronomy) |
| Zdroj: | The Astrophysical Journal. 484:741-760 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed and sizeable WD populations were found in all three. The location of these WDs in the color-magnitude diagram, their mean mass of 0.51($ \pm 0.03$)M$_{\odot}$, and their luminosity function confirm basic tenets of stellar evolution theory and support the results from current WD cooling theory. The WDs are used to extend the cluster main-sequence mass function upward to stars that have already completed their nuclear evolution. The WD/red dwarf binary frequency in M4 is investigated and found to be at most a few percent of all the main-sequence stars. The most ancient WDs found are about 9 Gyr old, a level which is set solely by the photometric limits of our data. Even though this is less than the age of M4, we discuss how these cooling WDs can eventually be used to check the turnoff ages of globular clusters and hence constrain the age of the Universe. |
| Databáze: | OpenAIRE |
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