Globular Clusters

Globular Clusters

Globular Cluster Ages
- Chaboyer, B., Demarque, P., Kernan, P. and Krauss, L.M. 1996, Science, 271, 957:"A lower Limit on the Age of the Universe"
- Chaboyer, B., Demarque, P. and Sarajedini, A. 1996, ApJ, 459, 558:"Globular Cluster Ages and the Formation of the Galactic Halo"
- Demarque, P. 1997, "The Ages of Globular Star Clusters", in The Extragalactic Distance Scale, STScI May 1996 Symposium, eds. M. Livio, M. Donahue & N. Panagia (Cambridge UP:Cambridge), p.30.
- Sarajedini, A., Chaboyer, B. & Demarque, P. 1997, Pub. Astron. Soc. Pacific, 109, 1321 :"The Relative Ages of Galactic Globular Clusters" (Review)
- Chaboyer, B., Demarque, P., Kernan, P. & Krauss, L.M. 1998, ApJ, 494, 96 :"The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem ?"
- Demarque, P., Kim, Y. -C. & Yi, S. 2002, in New Quests in Stellar Astrophysics: The Link between Stars and Cosmology, eds. M. Chavez, A. Bressan, A. Buzzoni & D. Mayya (Kluwer), p. 111 :"Update on Globular Cluster Ages" preprint pdf

Monte Carlo Age Histogram for the Oldest Globular Clusters (Chaboyer et al. 1998)

Star Mergers in Globular Clusters
- Sills, A.P., Bailyn, C.D and Demarque,P. 1995, ApJ, 455, L165:"Are Blue Stragglers Mixed During Collisions?"
- Sills, A., Lombardi, J.C.Jr., Bailyn, C.D., Demarque, P., Rasio,F.A. & Shapiro, S.L. 1997, ApJ, 487, 290 :"Evolution of Stellar Collision Products in Globular Clusters. I. Head-on Collisions"

Horizontal Branch Morphology and RR Lyrae Variables
- Lee, Y.-W., Demarque, P. & Zinn, R. J. 1990, ApJ, 350, 155:"The Horizontal-Branch Stars in Globular Clusters. I. The Period-Shift Effect, the Luminosity of the Horizontal- Branch, and the Age-Metallicity Relation (LDZI)"
- Horch, E., Demarque, P., Pinsonneault, M. H. 1992, ApJ, 388, L53:"The Evolution of High Metallicity Horizontal-Branch Stars and the Origin of the UV Light in Elliptical Galaxies"
- Lee, Y.-W., Demarque, P. & Zinn, R.J. 1994, ApJ, 423, 248: "Horizontal-Branch Stars in Globular Clusters. II. The Second Parameter Phenomenon (LDZII)"
- Koopmann, R.A., Lee, Y.-W., Demarque, P. & Howard, J.M., 1994, ApJ, 423, 380:"Mass Loss During the RR Lyrae Phase of the Horizontal Branch: Mass Dispersion on the Horizontal Branch and RR Lyrae Period Changes"
- Yi, S., Demarque, P. and Kim,Y.-C. 1997, ApJ, 482, 677 :"On the UV- Bright Phase of Metal Rich Horizontal-Branch Stars"
- Demarque, P., Zinn, R., Lee, Y.-W. & Yi, S. 2000, AJ, 119, 1398 : "The Metallicity Dependence of RR Lyrae Absolute Magnitudes from Synthetic Horizontal-Branch Models"
- Yong, H., Demarque, P. & Yi, S. 2000, ApJ, 531, 503:"Mass Loss on the Horizontal branch: An Application to NGC 6791"
- Lee, Y.-W., Joo, S.-J., Han, S.-I., Chung, C., Ree, C.-H., Sohn, Y.-J., Kim, Y.-C., Yoon, S.-J., Yi, S.K. & Demarque, P. 2005, ApJ, 621, 57L :"Super-Helium-rich Populations and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters"

LMC clusters and Calan-Yale Local Group Key Project

For a more detailed description of this research, return to the Department of Astronomy homepage, click on Research, then on Yale - Universidad de Chile Joint Program, then on Studies of Local Group Galaxies.
- Woo, J.-H., Gallart, C., Demarque, P., Yi, S. & Zoccali, M. 2001, to be published in Observed HR Diagrams and Stellar Evolution: the Interplay between Observational Constraints and Theory, ASP Conf. Ser., eds. Th. Lejeune & J. Fernandes, "Testing Overshoot with Intermediate-Age Magellanic Cloud Clusters" preprint ps
- Gallart, C., Zoccali, M., Bertelli, G., Chiosi, C., Demarque, P., Girardi, L., Nasi, E., Woo, J.-H. & Yi, S. 2002, AJ, 125, 742: "Testing intermediate-age stellar evolution models with VLT photometry of LMC clusters.I. The data"
- Woo, J.-H., Gallart, C., Demarque, P., Yi, S. & Zoccali, M. 2002, AJ, 125, 754: "Testing intermediate-age stellar evolution models with VLT photometry of LMC clusters.II. Analysis with the Yale models"
- Bertelli, G., Nasi, E., Girardi, L., Chiosi, C., Gallart, C. & Zoccali, M. 2002, AJ, 125, 770: "Testing intermediate-age stellar evolution models with VLT photometry of LMC clusters.III. Padova results"

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