Why astronomers aren't worried after a wobbly exoplanet vanished from view
A planet on an uneven schedule
Astronomers began observing TOI-2535 b with NASA’s TESS telescope in April 2019. TESS detects planets by measuring changes in a star’s brightness when a planet passes across its face.
The planet is about 1,000 light-years away and orbits its star every 8.25 days, much faster than Mercury circles the sun. Over seven years of observations, its transits arrived as much as six hours earlier or later than expected, and grew shorter and less pronounced.
A neighbor shifts its orbit
Researchers think TOI-2535 b has a nearby gas giant whose orbit is tilted in comparison. The planets’ gravitational interaction appears to make their orbits wobble, shifting TOI-2535 b out of the alignment needed for observers on Earth to see its transit.
Eclipses offer a comparison
The effect resembles the dynamics that keep eclipses from occurring on a perfectly regular schedule. UCLA astrophysicist Erik Petigura said that if the moon’s orbit were aligned with Earth’s path around the sun, an eclipse would happen every month.
Based on their calculations, the team expects TOI-2535 b’s next transit in 30 to 50 years. They may see its companion planet sooner, after it emerges from behind its star.
Key points
- TOI-2535 b disappeared from a TESS scan, but researchers say it did not evaporate.
- A nearby gas giant may be tilting the planet’s orbit through gravitational interaction.
- The planet’s transits shifted by up to six hours and became shorter and shallower.
- Researchers estimate its next transit may be 30 to 50 years away.