To date, more than 4000 exoplanets have been discovered. However an exoplanet found in 2004, has since disappeared from Hubble’s observations.
Direct evidence of a planet moving around the star Fomalhaut b was made using Hubble data.
When astronomers first discovered this exoplanet, it appeared to be as large as 3x Jupiter in size. Later images showed the exoplanet had shrunk dramatically.
The planet was very unusual because it was very bright in the light spectrum, but showed no infrared signature. It’s orbit was also very unusual.
Scientists are now trying to explain what they have observed, as now the planet has disappeared completely from observations.
One theory is that the planet never existed all, but rather a dense gas cloud was giving a false positive, and has been expanding and becoming less dense, appearing to disappear.