NASA's TESS Spots Record-breaking Stellar Triplets

Professional and amateur astronomers teamed up with artificial intelligence to find an unmatched stellar trio called TIC 290061484, thanks to cosmic “strobe lights” captured by NASA’s TESS (Transiting Exoplanet Survey Satellite).

The system contains a set of twin stars orbiting each other every 1.8 days, and a third star that circles the pair in just 25 days. The discovery smashes the record for shortest outer orbital period for this type of system, set in 1956, which had a third star orbiting an inner pair in 33 days.

Flickers in starlight helped reveal the tight trio, which is located in the constellation Cygnus. The system happens to be almost flat from our perspective. This means the stars each cross right in front of, or eclipse, each other as they orbit. When that happens, the nearer star blocks some of the farther star’s light.

Using machine learning, scientists filtered through enormous sets of starlight data from TESS to identify patterns of dimming that reveal eclipses. Then, a small team of citizen scientists filtered further, relying on years of experience and informal training to find particularly interesting cases.

Partly because the stars in the newfound system orbit in nearly the same plane, scientists say it’s likely very stable despite their tight configuration (the trio’s orbits fit within a smaller area than Mercury’s orbit around the Sun). Each star’s gravity doesn’t perturb the others too much, like they could if their orbits were tilted in different directions.

As the inner stars age, they will expand and ultimately merge, triggering a supernova explosion in around 20 to 40 million years.