Peanut Stars Share Outer Atmospheres

Contact binaries, often nicknamed "peanut stars," form when two stars orbit so closely that they touch and share a gaseous outer envelope. Both stars fill their Roche lobes, allowing the more massive star to transfer mass and energy to its companion. Although the shared envelope gives the system a peanut-like shape, the two components remain a binary rather than becoming one star. These arrangements can persist for millions or even billions of years.

Previous Fact Next Fact