Habitable zones about main sequence stars
1979; Elsevier BV; Volume: 37; Issue: 1 Linguagem: Inglês
10.1016/0019-1035(79)90141-6
ISSN1090-2643
Autores Tópico(s)Space Science and Extraterrestrial Life
ResumoCalculations show that a main sequence star which is less massive than the Sun has a continuously habitable zone about it which is not only closer in than the corresponding zone about the Sun, but is also relatively narrower. Let L(t) represent the luminosity after t billion years of a main sequence star of mass M, and let rinner and router represent the boundaries of the continuously habitable zone about such a star—that is, the zone in which an Earthlike planet will undergo neither a runaway greenhouse effect in the early stages of its history nor runaway glaciation after it develops an oxidizing atmosphere. Then our computer results indicate that routerrinner is roughly proportional to [L(3.5)L(1.0)]12. This ratio is smaller for stars less massive than the Sun (because they evolve more slowly), and the width of the continuously habitable zone about a main sequence star is therefore a strong function of the initial stellar mass. Our calculations show that rinner = router for M∼0.83M⊚ (i.e., K1 stars), and it therefore appears that there is no continuously habitable zone about most K stars, nor any about M stars.
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