3 items with the tag “proxies

  • Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements
    NAI 2009 Arizona State University Annual Report

    In our “follow the elements” strategy we work to refine searches for planetary systems likely to host life by identifying systems with favorable elemental compositions. Because some relevant elements or isotopes (for example 26Al) are difficult or impossible to observe due to low abundances or short lifetimes, we wish to find easily observable indicators of their presence. In most cases this involves identifying elements or isotopes that are either produced primarily by the same process as the isotope of interest or produced in unique ratios to other isotopes by that process. This requires simulating the synthesis of isotopes in stars and supernovae and their ejection into space and incorporation into forming planetary systems.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements
    NAI 2010 Arizona State University Annual Report

    Many of the elements important to life or to the development of potentially habitable solar systems are difficult or impossible to observe directly. We are working to understand where these elements are produced in stars and whether they correlate with elements that are more easily observed. This effort requires modeling of the dynamics and nuclear burning in supernova explosions to determine what elements are produced together and, equally important, how the ejected material is incorporated into the gas that forms stars and planets. We are also observing a region of star formation to detect the signature of enrichment of newly formed sunlike stars by the explosion of their nearby, more massive cousins.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements
    NAI 2011 Arizona State University Annual Report

    In this task we explore how key elements and radioactive isotopes are created by nucleosynthesis during the explosions of massive stars. We also study the formation and composition of structures in supernova explosions that may be relevant to delivery of bioessential elements to forming solar systems. In particular, we have investigated how the bioessential elements Ca and Fe are produced during supernovae. We have discovered that they are produced by 6 distinct nucleosynthetic pathways, and that their relative abundances can be probed by observations of the gamma-ray radiation from the radioactive decay of the isotopes 44Ti and 56Ni into 44Ca and 56Fe. We also have investigated the co-production of O isotopic anomalies with the short-lived radionuclide 26Al. We find that delivery of 26Al to the early solar system would not necessarily have altered significantly its O isotopic composition.

    ROADMAP OBJECTIVES: 1.1 3.1