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地球般大小的行星都有相对圆形轨道的研究发现

发布时间:2018-09-20 文章编辑:admin

For decades, researchers have studied our planet’;s orbit with growing interest: is there something special about the way the Earth revolves around the Sun, is it a necessary condition for life to emerge? A team of researchers from MIT studied 74 Earth-sized exoplanets and reports that all of them have fairly circular orbits around their stars。

Circular vs Eccentric

Image courtesy of NASA。

The study, published in the Astrophysical Journal, reports that the 74 exoplanets revolve their 28 stars at relatively circular trajectory, standing in stark contrast to larger exoplanets, which have much more eccentric orbits。

“Twenty years ago, we only knew about our solar system, and everything was circular and so everyone expected circular orbits everywhere,” says Vincent Van Eylen, a visiting graduate student in MIT’s Department of Physics。 “Then we started finding giant exoplanets, and we found suddenly a whole range of eccentricities, so there was an open question about whether this would also hold for smaller planets。 We find that for small planets, circular is probably the norm。”

It’;s not clear why this happens, or whether this has something to do with with their size, or whether it’;s a coincidence。 Having a circular orbit is one of the proposed requirements for supporting life; otherwise, the climatic swings between seasons are simply too massive。 It’;s not impossible for life to exist on planets with eccentric orbits, but it just seems much more unlikely。

“If eccentric orbits are common for habitable planets, that would be quite a worry for life, because they would have such a large range of climate properties,” Van Eylen says。 “But what we find is, probably we don’t have to worry too much because circular cases are fairly common。”

All in all, the study brings good news for detecting life outside our solar system。

本文源自: 环亚娱乐