Epsilon Eridani's debris belt is almost circular

Astronomers reanalyzed ALMA 1.29-millimeter observations of epsilon Eridani, a Sun-like star only 10.5 light-years away that hosts the nearest detected debris disk and a known Jupiter analogue. Two disk models place 99.7-percent upper limits of 2.6 percent on forced eccentricity and 6.8 percent on the belt particles' proper eccentricity. One fit shows tentative four-sigma evidence for a small forced eccentricity of 1.62 percent, but the broader conclusion is that the outer belt is dynamically cold and close to circular.

Combining the ALMA limits with Spitzer and Webb imaging, the team explored additional planets compatible with the belt's shape. Depending on orbit, an unseen companion from roughly 0.0002 to 0.3 Jupiter masses could remain between about 6 and 60 astronomical units. Those are allowed architectures, not detections. The accepted paper constrains how a planet could sculpt the disk without claiming that another planet—or life—has been found.

Why it matters

Epsilon Eridani is one of the nearest planetary systems and a frequent target for direct imaging. A dynamically quiet belt supplies a stringent, local laboratory for testing planet-disk interactions and planning future searches.

What the source establishes

Worth Revisiting · Accepted Astrophysical Journal manuscript posted September 30. The belt geometry is measured through ALMA modeling; the extra-planet ranges are constraints on possibilities, not a new object.