Study: Warm Jupiters Might Have Many Unexpected Planetary Companions

A new study from the University of Toronto revealed that many of the exoplantes called "warm Jupiters" were not alone in their system and have unexpected planetary companions.

Warm Jupiters are gas-giants that are comparable in size to the gas-planets in our solar system. However, unlike our gas-planets, warm Jupiters orbit around their parent star with approximately same distance as the inner planets of our solar system. Warm Jupiters usually take 10 to 200 days to complete a single orbit.

The study, published in the Astrophysical Journal, suggests that there are two types of warm Jupiters. The first types have companions, while the other type don't have companion. The presence and absence of companion might actually explain how these warm Jupiters got to their current location.

"Our findings suggest that a big fraction of Warm Jupiters cannot have migrated to their current positions dynamically and that it would be a good idea to consider more seriously that they formed where we find them," explained Chelsea Huang, a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, in a statement.

For the study, the researchers analyzed four years worth of data from the observations of Kepler space Telescope. Astronomers discovered that 11 of the 27 warm Jupiters they studied have companions ranging in size from Earth-like to Neptune-like.

These findings suggests that it is possible for warm Jupiters to be formed in their current location, as opposed to the commonly accepted theory that warm Jupiters have migrated inwards to their parent star. Migration theory was proposed due to the close distance of warm Jupiters to their parent star, making it seems like impossible to accumulate large, gas giant-like atmosphere.

During migration, the gravity of any warm Jupiter would have disrupted neighboring and companion planets, ejecting them from the solar system. Researchers are then lead to believe that warm Jupiters that have planetary companions might have been formed near their parent star.