Scientists described the discovery of an exoplanet with three stars. They described their work with direct imaging technology to study the triple-star system HD 131399. Researchers spotted what they believed to be an exoplanet approximately four times the size of Jupiter. They noted its apparent odd orbital system. The planet appeared to orbit just one of the stars while the other two stars were farther away.
Another team of researchers found evidence suggesting that the planet was not a planet after all was from a background object which can be a dwarf star. They said that the object was much more likely to be something moving unusually fast in the background in a path that coincided with star system HD 131399.
The study led scientists to take another look at their earlier work and then to observe star system HD 131399 over an extended period of time. This allowed scientists to capture imagery of the star system in motion. They discovered “a clear parallax difference between the object and HD 131399”. This confirmed that the light from what they had thought in 2016 was a planet was actually coming from much farther away than light from the stars in the system. This rule out the possibility that the light was from a planet in that system. It was instead from something much farther away in the distant background.
Scientists have suggested that their work highlights the risk in making assumptions about stationary backgrounds in star systems. They hope that their experience will help to improve astronomy.