Notice: This is an archived and unmaintained page. For current information, please browse astrobiology.nasa.gov.
NAI
Login
NASA: National Aeronautics and Space Administration

nai
You are here: Home » Annual Science Reports » Team » Report

2014 Annual Science Report

Arizona State University Reporting  |  SEP 2013 – DEC 2014

Astrophysical Controls - Task 2 - Model the Chemical & Dynamical Evolution of Massive Stars

Project Summary

Stars create the chemical elements heavier than hydrogen and helium, with the majority arising from the lives and violent deaths of massive stars in supernova explosions. The starting chemical composition of stars also affects their evolution and that of their associated planets. We have performed computational simulations for a large range of stellar masses to provide predictions for important stellar characteristics (i.e., brightness, temperature, stellar winds, composition) over the stars’ lifetimes and made the data available to the public. We have also simulated the explosions of massive stars to predict the chemical abundances of material ejected from the dying stars and how that material is distributed in the surrounding universe. As a complement, we are modeling how the habitable zones and planets of stars with different abundances evolve.

4 Institutions
3 Teams
3 Publications
0 Field Sites
Field Sites

Project Progress

The composition of stars strongly influences their evolution and properties of their planets. Patrick Young and Amanda Truitt (ASU) have created a grid of stellar models for 0.5 – 1.2 solar masses, 0.1 to 1.5 times solar metallicity, and O/Fe ratios of 0.5 to 2 times solar with the TYCHO stellar evolution code. These models include predicted habitable zone locations as a function of time for each stellar model for a range of assumptions. With Jeremy Dietrich (Harvard) they have created a web-based interface for accessing and visualizing simulations data and producing interpolated stellar and habitable zone evolutionary tracks for any arbitrary combination of mass, metallicity, and O/Fe ratio in the parameter space. The majority of stars in the solar neighborhood of interest to astrobiologists should fall in this range. A pilot project for characterizing individual stars and planetary systems with detailed compositional information was carried out for tau Ceti (see also task 7) by Young, Truitt, and Michael Pagano (ASU). The TYCHO stellar evolution code is updated to start production of massive star models using the compositional variations determined from task 7 and used here for low mass stars.

Publications

  • Pagano, M., Truitt, A., Young, P. A., & Shim, S-H. (2015). THE CHEMICAL COMPOSITION OF τ CETI AND POSSIBLE EFFECTS ON TERRESTRIAL PLANETS. The Astrophysical Journal, 803(2), 90. doi:10.1088/0004-637x/803/2/90

  • Truitt, A., Young, P. A., Spacek, A., Probst, L., & Dietrich, J. (2015). A CATALOG OF STELLAR EVOLUTION PROFILES AND THE EFFECTS OF VARIABLE COMPOSITION ON HABITABLE SYSTEMS. The Astrophysical Journal, 804(2), 145. doi:10.1088/0004-637x/804/2/145

  • Young, P. A., Desch, S. J., Anbar, A. D., Barnes, R., Hinkel, N. R., Kopparapu, R., … Truitt, A. (2014). Astrobiological Stoichiometry. Astrobiology, 14(7), 603–626. doi:10.1089/ast.2014.1143