Galway PhD student leads major discovery of second planet 

By Rosa Boran

A University of Galway PhD student has led a team of astronomers to the discovery of a second planet, WISPIT 2c, in the same system where another planet was discovered last year.  

WISPIT 2c, is estimated to be around 5 million years old and roughly ten times the mass of Jupiter. 

The study was led by PhD researcher Chloe Lawlor from the University of Galway’s Centre for Astronomy and the Ryan Institute. Ms Lawlor worked in collaboration with PhD student Richelle van Capelleveen, Leiden Observatory, Netherlands and postdoctoral researcher Guillaume Bourdarot, Max Planck Institute for Extraterrestrial Physics in Garching, Germany.

“There was definitely an element of disbelief. I didn’t expect to be the one to find a second planet in the system,” Ms Lawlor said. “When I sent the spectrum to my supervisor Dr Christian Ginski, it was a huge shock and upon further examination, he confirmed I’d found a planet!” Lawlor said.  

The discovery is of a second forming planet orbiting the star WISPIT 2, making it only the second known example of a multi-planet system caught in the act of formation.  

The team detected the planet by using the European Southern Observatory’s Very Large Telescope Interferometer (VLTI) in Chile.  

They identified carbon monoxide gas which has a strong, distinctive chemical signature commonly found in the atmospheres of young giant planets.  

The recently upgraded GRAVITY+ instrument was also used, allowing astronomers to combine the light of four eight-metre telescopes, making it possible to pick out the faint planet despite the brightness of WISPIT 2.  

Professor Frances Fahy, Director of the Ryan Institute, University of Galway, said the discovery offers scientists “a rare opportunity to study how massive planets form and evolve, shedding new light on the early processes that ultimately led to the formation of Earth.”

She highlighted its broader significance saying, “Discoveries like this capture the imagination and can inspire a whole new generation of astronomers.”