Q&A WITH A STELLAR ECLIPSE SPECIALIST

Many stars are gravitationally locked inside multi-star systems, but a rare new triple-star system has set a new record for how cosy these clusters can get

- Vaselin Kostav

What is a triply eclipsing three-star system?

While orbiting their parent star(s), planets can sometimes cross the line of sight between the star and Earth. When they do, they produce a 'transit' that we can detect. Eclipsing star systems are similar. Instead of a planet, a star moves in front of another star, blocking some of its light. Triply eclipsing three-star systems consist of three stars orbiting a common gravitational centre. Two stars closely orbit one another, and both orbit a more distant third star. Sometimes, from Earth we can detect three sets of eclipses from these systems.

What did your study discover?

We discovered a triply eclipsing three-star system called TIC 290061484, consisting of a pair of inner stars orbiting one another in about 1.8 days and a third star in a wider orbit of around 24.5 days.

What is significant about TIC 290061484?

It's the shortest known orbit in a triple system, by far. The previous record-holder, Lambda Tauri, was discovered over 60 years ago and had an outer orbit of 33 days. Since then, many people have looked for even shorter outer periods.