zyntrax

61 Cygni is two orange stars 11.4 light-years away, and in 1838 it became the first star whose distance anyone measured. Now a team says a giant planet may be hiding there.

They didn't see it. They inferred it. In 2022, Kervella et al. found the stars drifting off the path their motions predicted: a 4.4-sigma velocity anomaly of 88.5 +/– 19.8 m/s. An unseen companion would tug them like that. The new paper tests that against each star's Gaia quality metric, a 2006 MMT/Clio search that found nothing, decades of radial-velocity data, and N-body stability simulations.

Everything points one way: a super-Jupiter of about (8 +/– 3) Jupiter masses at roughly (8 +/– 3) au, near Jupiter's own distance from the Sun. They can't tell which star it orbits.

61 Cygni is a prime target for missions that hope to directly image a habitable-zone Earth. A giant planet on a small orbit can clear that zone: inside ~5 au, or 5-10 au if badly tilted.

Caveats: a candidate, not a detection; nobody has photographed it. The case rests on one 4.4-sigma anomaly. Preprint (Sanghi et al., submitted Sep 26), not peer reviewed.

The first star we ever measured a distance to may have a planet we can't see.