It’s been a big year for exoplanet news. A host of new planets and planetoids have been discovered in 2016, some even in our own solar system. As astronomical technology and computer power increases, new and unusual discoveries about our universe are becoming more and more common. Just this week, an international team of astronomers announced the discovery of two strange planets that defy current astronomical knowledge.
According to a release by Phys.org, these gas giants are much larger than they should be based on their masses. The stars, HAT-P-65 and HAT-P-66, are both around 3,000 light years away and both are less massive than our closest gas giant, Jupiter. Interestingly, however, both have radii much larger than Jupiter’s. Astronomers are currently unable to explain why these planets are so large yet have such small masses relative to their size.
The team behind this finding used the Hungarian Automated Telescope Network (HATNet) run by the Harvard-Smithsonian Center for Astrophysics and has published their findings in the journal Earth and Planetary Astrophysics. According to their research, the team believes that these stars are made so unusually large and hot by their close proximity to their stars:
[The data] suggests that after contracting during the pre-main-sequence, close-in giant planets are re-inflated over time due to the increasing level of irradiation received from their host stars.
As with any astronomical discovery, researchers are continuing to gather data before they make any conclusions about the unusual sizes of the two gas giants.
The authors of this study note that it is still unknown if such close-in gas giants are affected by the nucleosynthetic activities of their host stars or whether some internal force is behind the size fluctuation:
While it is well known that the radii of close-in giant planets are correlated with their equilibrium temperatures, whether or not the radii of planets increase in time as their hosts evolve and become more luminous is an open question.
While this research has left many astronomers scratching their heads at these two strange new planets, the discovery of the planets might lead to further data on the properties of gas giants. The researchers write that if they and other astronomers can gather a larger list of planets displaying such strange mass-to-radius ratios, then more definitive conclusions might be able to be drawn in the future about other anomalous planets.