Matkovic, A.Guzmán, R.Sánchez Blázquez, P.Cardiel López, NicolásGorgas García, Francisco Javier2023-06-202023-06-2020091. Dekel, A., & Silk, J., 1986, ApJ, 303,39 2. Lin, D. N. C, & Faber, S. M., 1983, ApJ, 266, L21 3. Matkovic, A., Guzmán, R., Sánchez Blázquez, P., Gorgas, J., Cardiel, N., and Gruel, N., accepted to ApJ, arXiv:0810.3237 4. Matkovic, A. 2008, Ph.D. Dissertation, Internal Kinematics and Stellar Populations of Dwarf Early-Type Galaxies in the Coma Cluster 5. Moore, B., Katz, N., and Lake, G. 1996, ApJ, 457,455 6. Smith, R.J., Hudson, M.J., Nelan, J.E., Moore, S.A., Quinney, S.J., and 6 co-authors 2004, AJ, 128, 1558S 7. Thomas, D., Maraston, C, & Kom, A. 2004, MNRAS, 351, L19 8. Trippico, M. J., & Bell, R. A. 1995, AJ, 110,30350094-243Xhttps://hdl.handle.net/20.500.14352/51296© 2009 American Institute of Phiysics. International Conference on Probing Stellar Populations out to the Distant Universe (2008. Cefalu, Italy). I thank the SOC for financial support to attend the conference.We derive ages, metallicities and [alpha/Fe] ratios for dwarf early-type galaxies (dE/dS0) in the center and a region believed to be infalling into the Coma cluster. We find that a set of metallic indices cannot be described by linear relations with velocity dispersion (sigma), while another group of indices exhibits linear index-sigma relations. dE/dS0 galaxies in the core of the cluster are on average younger, and have lower metallicities and lower alpha-ratios (solar to sub-solar) than the more luminous elliptical galaxies. On the other hand, dEs/dSos in the infall region of Coma form a less homogeneous population. We find an unusually high fraction of dE/dS0s with high [alpha/Fe] ratios, suggesting short time scales for the star formation histories for these galaxies. Furthermore, the dE/dS0s with high alpha-ratios have a range of ages and metallicities implying multiple formation scenarios where some galaxies have experienced their short star formation bursts at more recent epochs.engjournal articlehttp://link.aip.org/link/?APCPCS/1111/23/1http://scitation.aip.org/open access52IndexesMatterAstrofísicaAstronomía (Física)Física atmosférica2501 Ciencias de la Atmósfera