Fomalhaut star system is a triple

Fomalhaut A (center) tugs not only on a debris ring (orange circle) but also a planet and two other stars (not shown).

P. Kalas and J. Graham/UC Berkeley, M. Clampin, GSFC, NASA, ESA

Planets and debris aren’t the only things gravitationally bound to Fomalhaut A, a star twice the mass of the sun that sits 25 light-years away in the constellation Piscis Austrinus. It turns out that not one but two other stars are also in its clutches. Astronomers describe the triple star system in a paper posted October 3 on arXiv.org and accepted for publication in the Astronomical Journal. The team notes that the Fomalhaut triple system is one of the most massive and widest among multiple-star systems closest to Earth. The discovery of the new star in the system may help explain the eccentric orbit of the contentious exoplanet Fomalhaut b.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.