Habitable Zone Greatly Influenced by Time and Host Star Parameters

A CATALOG OF STELLAR EVOLUTION PROFILES AND THE EFFECTS OF VARIABLE COMPOSITION ON HABITABLE SYSTEMS

Authors:

Truitt et al

Abstract:

We present stellar evolution models for 0.5–1.2 ${{M}_{\odot }}$ at scaled metallicities of 0.1–1.5 Z$_{\odot }$ and O/Fe values of 0.44–2.28 O/Fe$_{\odot }$. The time-dependent evolution of habitable zone (HZ) boundaries is calculated for each stellar evolution track based on stellar mass, effective temperature, and luminosity parameterizations. The rate of change of stellar surface quantities and the surrounding HZ position are strong functions of all three quantities explored. The range of orbits that remain continuously habitable, or habitable for at least 2 Gyr, are provided. The results show that the detailed chemical characterization of exoplanet host stars and a consideration of their evolutionary history are necessary to assess the likelihood that a planet found in the instantaneous HZ has had sufficient time to develop a biosphere capable of producing detectable biosignatures. This model grid is designed for use by the astrobiology and exoplanet communities to efficiently characterize the time evolution of host stars and their HZs for planetary candidates of interest.