Astronomers have discovered a massive exoplanet, estimated to be between three and ten times the size of Jupiter, concealed within the gas and dust surrounding a young star named MP Mus. Initially thought to be devoid of planets, further observations using data from the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Space Agency’s Gaia mission revealed otherwise.
Led by researchers from the University of Cambridge, an international team detected a significant gas giant in MP Mus's protoplanetary disc. This is notable as it marks the first time Gaia has identified an exoplanet within such a disc. The findings were published in Nature Astronomy.
Dr Álvaro Ribas from Cambridge’s Institute of Astronomy stated, “We first observed this star at the time when we learned that most discs have rings and gaps, and I was hoping to find features around MP Mus that could hint at the presence of a planet or planets.” Initial ALMA observations showed no signs of planet formation. However, subsequent analysis at longer wavelengths revealed previously obscured structures.
Simultaneously, Miguel Vioque from the European Southern Observatory noted unusual wobbling in MP Mus using Gaia data. “My first reaction was that I must have made a mistake in my calculations,” said Vioque. The wobbling aligned with new findings presented by Ribas regarding an inner cavity in the disc.
The combined data suggests a gas giant less than ten times Jupiter's mass is orbiting MP Mus at one to three times Earth's distance from the Sun. “Our modelling work showed that if you put a giant planet inside the new-found cavity, you can also explain the Gaia signal,” Ribas explained.
This discovery highlights potential challenges in detecting young planets due to interference from surrounding material. Future telescope advancements may offer deeper insights into these hidden planetary bodies.
The research received support from various organizations including the European Union’s Horizon Programme and UK Research and Innovation (UKRI).