Taiwanese scientists have investigated the strange behavior of exoplanet HAT-P-12b, according to which the irregularity of the passages through the disk of its star was picked up. According to researchers, this may indicate the presence of another world in this star system.
Planet HAT-P-12b
Astronomers from Taiwan’s Tsing Hua University have tried to explain what’s going on with the planet HAT-P-12b and found out something interesting about the system. They reported the results in the journal New Astronomy.
HAT-P-12 is a star in the constellation Canes Venatici that became famous after the discovery of a planet orbiting it in 2009. HAT-P-12b is a “hot Saturn” with a mass 21% of that of Jupiter, and it makes one orbit around the star in just over 3 days.
This planet is transiting, meaning it passes through the disk of its star from time to time. This makes it a convenient object of observation, but apart from that it has little of interest. The only thing that interested scientists in it: the time of its transits can differ from the average value for up to 152 s.
The last fact may not seem so important, but the planet’s spin is a very precise thing and a 2 minute deviation in transit time over such a short period of time is a lot. It is this feature that scientists have attempted to explain in a new study.
What’s behind the planet’s strange behavior
Fortunately, they had a fairly large observational data set for HAT-P-12b: as many as 46 light curves. By the way, the star has the proper name Komondor, and the planet is Puli. Both are names of dog breeds, which is due to the fact that the system is located in the constellation Canes Venatici.
The available data allowed scientists to test four possible models that could explain why the planet behaves this way. The first model assumed that HAT-P-12b was an ordinary planet orbiting quietly around its star. However, it could not explain the observations fundamentally.
The second model was based on the assumption that the planet was falling into the sun. But then, the speed of transits would have to slowly increase, while it jumps back and forth. The third model was based on the assumption that the planet’s orbit is highly eccentric and thus constantly shifting. It matched the observations pretty well, but there was a model that matched them better.
We are talking about a case where another planet would orbit near HAT-P-12b and its gravity would influence the behavior of the strange world. Scientists calculated that if it had a mass of about 2% of Jupiter’s and orbited in 6.24 days, it would have exactly the effect on transits that was observed.
According to phys.org
