5,468 research outputs found

    Candidate Members and Age Estimate of the Family of Kuiper Belt Object 2003 EL61

    Get PDF
    The collisional family of Kuiper belt object (KBO) 2003 EL61 opens the possibility for many interesting new studies of processes important in the formation and evolution of the outer solar system. As the first family in the Kuiper belt, it can be studied using techniques developed for studying asteroid families, although some modifications are necessary. Applying these modified techniques allows for a dynamical study of the 2003 EL61 family. The velocity required to change orbits is used to quantitatively identify objects near the collision. A method for identifying family members that have potentially diffused in resonances (like 2003 EL61) is also developed. Known family members are among the very closest KBOs to the collision and two new likely family members are identified: 2003 UZ117 and 1999 OY3. We also give tables of candidate family members which require future observations to confirm membership. We estimate that a minimum of ~1 GYr is needed for resonance diffusion to produce the current position of 2003 EL61, implying that the family is likely primordial. Future refinement of the age estimate is possible once (many) more resonant objects are identified. The ancient nature of the collision contrasts with the seemingly fresh surfaces of known family members, suggesting that our understanding of outer solar system surfaces is incomplete.Comment: 22 pages, 5 figures, accepted to AJ, author's cv available at http://www.gps.caltech.edu/~dari

    The Stellar Population of High Redshift Galaxies

    Full text link
    Using the VLT we have obtained high quality spectra of about 70 high redshift (1- 4.6) galaxies within the FORS Deep Field (FDF). As expected most of them turn out to be (bright) starburst galaxies and the observed spectra agree with synthetic ones. The equivalent width of the CIV(1550) absorption line turns out to be a good indicator for the galaxies metallicity. Furthermore our high-z starburst galaxies show increasing metal content with decreasing redshift. Compared with local starburst galaxies they tend to be overliminous for their metallicity.Comment: 3 pages, including 4 eps-figures, Latex2e, to appear in proceedings of MPA/ESO/MPE/USM Joint Astronomy Conference on "Lighthouses of the Universe" (Eds.: R. Sunyaev, M. Gilfanov, E. Churazov

    Gender types, self-esteem, and academic achievement in middle school students

    Get PDF
    The relationship among gender typing, self-esteem, and academic achievement was investigated in 314 middle school participants. Participants were administered the Children’s Sex Role Inventory (CSRI) and the Coopersmith Self-Esteem Inventory-School Form (CSEI). The results of the CSRI and CSEI were compared to each participant\u27s score on the California Achievement Test (CAT). Analysis of variance, chi-square, and Pearson product moment correlation\u27s were utilized to assess relationships among the variables. Results indicated that, in the current sample, self-esteem and achievement were unrelated, aschematic characteristics were correlated with high achievement, girls exhibited higher achievement than boys, both boys and girls responded most frequently to androgyny, and ethnic differences were noted. Implications of the results will be discussed
    • …