The Far Distant Future of Alpha Centauri
M. Beech (2011), JBIS, 64, 387-395Refcode
: Stars, structure and evolution, Centauri, orbital evolution, Planets, habitabilityAbstract:
A study is made of the dynamical evolution of the Centauri star system. On the basis that Centauri is composed of the twin Sun-like binary Cen AB and the ternary M-dwarf star Proxima Centauri, we consider the affects of mass loss, first from Cen A and then from Cen B upon the systems orbital characteristics and gravitational bound state. We find that as a result of system mass loss during the advanced evolutionary stages of Cen A that Proxima becomes unbound in approximately 3.5 billion years from the present. We also find that additional mass loss during the advanced evolutionary stages of Cen B results in the disassociation of Cen AB itself in about 12 billion years. The currently iconic Centauri system will ultimately disassemble, therefore, into two white dwarfs (the remnants of Cen A and Cen B) and one M-dwarf (Proxima), which will ply independent and steadily diverging paths about the galactic center. In terms of the potential exploration and even human colonization of hypothetical planets within the system, we find that Proxima Centauri offers the longest-lived and potentially most stable environment in which to settle. In contrast, Cen A will evolve away from the main sequence and enter its giant stage of evolution in about 3 billion years from now, and accordingly any (hypothetical) planets within its habitability zone will become uninhabitable. We additionally find that the habitability zone about Cen B will also be sterilized as Cen A evolves through its red giant phase.
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