Illustration of the binary stars (IMAGE) Northwestern University Caption Illustration of the oldest known pair of ultracool dwarf stars that orbit each other so closely, they take less than one Earth day to revolve around each other. Credit Adam Burgasser/UC San Diego Usage Restrictions Add credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.