Precise new measurements reveal Tabby's Star shares a complex orbital dynamic with a companion star, potentially explaining its irregular luminosity dips.
Located 1,470 light-years away in the Cygnus constellation, KIC 8462852—known as Tabby's Star—has fascinated astronomers since its 2015 discovery due to its irregular, unpredictable brightness drops, reaching up to 22%. These far exceed the typical 1% dips from transiting exoplanets, which occur regularly.
The dimming also affects some wavelengths more than others, ruling out solid objects like a hypothetical extraterrestrial megastructure, which would block light uniformly across the spectrum.
Instead, leading astronomers point to clouds of dust or debris from disintegrating comets or colliding asteroids. A recent study strengthens this hypothesis.
University of Arizona researchers, led by Logan Pearce, have long suspected a binary companion to KIC 8462852. Their work, accepted for publication in The Astrophysical Journal, drew on Keck Telescope observations in Hawaii and Gaia satellite data for precise astrometry of the faint nearby star.
The study confirms it: the stars are 880 astronomical units apart—< strong>about 132 billion kilometers. Tabby's Star (KIC 8462852 A) is 1.36 times the Sun's mass and 1.5 times its radius; its red dwarf companion (KIC 8462852 B) is roughly half the Sun's size and mass.
The wide orbit makes direct effects on A unlikely, but researchers propose gravitational tugs could destabilize small orbiting bodies. These interactions might stretch and fragment them, forming debris clouds that cause the observed dimming.
Computer simulations of such wide binaries show this sensitivity to perturbations. For now, this emerges as the strongest explanation, though further observations are essential to clarify their interplay.
