Image: This artist’s conception shows a lump of material in a swirling, planet-forming disk. (Credit: NASA/JPL-Caltech)
Astronomers have witnessed odd behavior around a young star. Something, perhaps another star or a planet, appears to be pushing a clump of planet-forming material around. The observations, made with NASA’s Spitzer Space Telescope, offer a rare look into the early stages of planet formation.
Planets form out of swirling disks of gas and dust. Spitzer observed infrared light coming from one such disk around a young star, called LRLL 31, over a period of five months. To the astronomers’ surprise, the light varied in unexpected ways, and in as little time as one week. Planets take millions of years to form, so it’s rare to see anything change on time scales we humans can perceive.
One possible explanation is that a close companion to the star — either a star or a developing planet — could be shoving planet-forming material together, causing its thickness to vary as it spins around the star.
“We don’t know if planets have formed, or will form, but we are gaining a better understanding of the properties and dynamics of the fine dust that could either become, or indirectly shape, a planet,” said James Muzerolle of the Space Telescope Science Institute, Baltimore, Md. Muzerolle is first author of a paper accepted for publication in the Astrophysical Journal Letters. “This is a unique, real-time glimpse into the lengthy process of building planets.”