Planets Form Earlier Than Thought Around Baby Stars

The Sun and its planets formed out of the solar nebula, around 4.6 billion years ago. But what was the delay between the Sun's formation and the planets? Astronomers have surveyed 78 protoplanetary disks in the Ophiuchus star-forming region and seen examples of every step in the planetary formation process. They found that the planets start forming much earlier than previously believed, when the disk is still filled with gas and dust, growing together with their host stars.

Jun 27, 2025 - 04:12
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Planets Form Earlier Than Thought Around Baby Stars

Images of protoplanetary disks in the Ophiuchus star-forming region, created with super-resolution imaging with sparse modeling versus a conventional imaging method. The resolution is shown by the white ellipse in the lower left of each panel, with a smaller ellipse indicating higher resolution. The white line in the lower right of each panel indicates a scale of 30 AU. The evolution stage of the central stars progresses from left to right, and from top to bottom in the same row. Credit: ALMA(ESO/NAOJ/NRAO), A. Shoshi et al.

The Sun and its planets formed out of the solar nebula, around 4.6 billion years ago. But what was the delay between the Sun's formation and the planets? Astronomers have surveyed 78 protoplanetary disks in the Ophiuchus star-forming region and seen examples of every step in the planetary formation process. They found that the planets start forming much earlier than previously believed, when the disk is still filled with gas and dust, growing together with their host stars.