We did know something about this system already, but more work has led to today’s announcement.
Astronomers have never seen anything like this before, says Space.com: Seven Earth-size alien worlds orbit the same tiny, dim star, and all of them may be capable of supporting life as we know it, a new study reports.
“Looking for life elsewhere, this system is probably our best bet as of today,” study co-author Brice-Olivier Demory, a professor at the Center for Space and Habitability at the University of Bern in Switzerland, said in a statement.
The exoplanets circle the star TRAPPIST-1, which lies just 39 light-years from Earth — a mere stone’s throw in the cosmic scheme of things. So speculation about the alien worlds’ life-hosting potential should soon be informed by hard data, study team members said.
“We can expect that, within a few years, we will know a lot more about these planets, and with hope, if there is life there, [we will know] within a decade,” co-author Amaury Triaud, of the Institute of Astronomy at the University of Cambridge in England, told reporters on Tuesday (Feb. 21).
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The six inner planets are in near-resonance, meaning their orbital periods are related to each other by a ratio of two small integers. This arrangement suggests that the worlds formed farther out in the system and then migrated in to their current positions, study team members said.
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For the six inner planets [1b to 1g] (7th lacks accurate data so far) we find the synodic period ratios line up like this:
g-f : f-e = 2:1
f-e : e-d = 3:2
e-d : d-c = 2:1
d-c : c-b = 3:2
[g-f : c-b = 9:1]
The exactness of the ratios is very good.