Amateur astronomers found nebulae around two stars, revealing hidden binary systems.

Astronomers surveying faint planetary nebulae found two pulsating stars wrapped in glowing gas clouds discovered by amateur astronomers. These clouds did not look normal. One, named StDr Objet 14, looks like a double-ring bull's-eye. The other, StDr 4, forms a bow shock shape inside a larger cloud. When the researchers analyzed the light from both systems, they discovered that neither central star is alone. Each system is a symbiotic binary. In this pair, a cool, swollen red giant star constantly leaks gas, and a small, hot companion star pulls in that gas with its gravity. One star, GR Cyg, is a cool carbon star that also shot out a knot of gas about 1.6 arcsec away. The other, [D75] 141, is a red giant whose gas may be colliding with an interstellar cloud. These accidental finds show that many more of these star pairs remain hidden in space.

Why it matters

This discovery hints at many more symbiotic stars hiding in our galaxy. Astronomers can now search more effectively, improving our knowledge of how stars evolve and interact.

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