As gas giants go, Neptune might be a gentle one.
Scientists studying pairs of planetoids in the outer solar system say they likely were moved there by the most distant planet from the sun as it settled into its orbit. But the fact that these small interlopers in the Kuiper Belt remain loosely bound to each other suggests Neptune nudged, rather than shoved, them to their current positions.
That’s the findings of a recent study of these objects, known as “blue binaries,” done with the Gemini and Canada-France-Hawaii telescopes atop Mauna Kea.
Gemini astronomer Meg Schwamb said the research gives astronomers greater insight into what was going on during the early days of the solar system, including how Neptune and the other gas giants migrated to their current paths.
“They (planetoids) are so tenuously bound to each other that Neptune had to basically move outward very slowly, very gracefully,” she said.
Neptune might have moved as much as 10 astronomical units (1 au is the distance from the Earth to the sun) within the first 800 million years, said Schwamb, who co-authored the report.
Schwamb said these planetoids, which are much smaller than the dwarf planet Pluto, were the material that formed the core of the gas planets, and possibly terrestrial ones.
“They’re like fossils sitting in plain view but nobody noticed them,” she said.
The research could improve models of the early solar system.
“The broad strokes we’ve always known but the devil is in the details,” Schwamb said.
The study was led by Wes Fraser of Queen’s University in Belfast, Northern Ireland.
Email Tom Callis at tcallis@hawaiitribune-herald.com.
