Astrophysicists Find "Impossible" Planet

SpuriousLogic writes "Scientists have discovered a planet that shouldn't exist. The finding, they say, could alter our understanding of orbital dynamics, a field considered pretty well settled since the time of astronomer Johannes Kepler 400 years ago. The planet is known as a 'hot Jupiter,' a gas giant orbiting the star Wasp-18, about 330 light years from Earth. The planet, Wasp-18b, is so close to the star that it completes a full orbit (its "year") in less than an Earth day, according to the research, which was published in the journal Nature. Of the more than 370 exoplanets — planets orbiting stars other than our sun — discovered so far, this is just the second with such a close orbit. The problem is that a planet that close should be consumed by its parent star in less than a million years, say the authors at Keele University in England. The star Wasp-18 is believed to be about a billion years old, and since stars and the planets around them are thought to form at the same time, Wasp-18b should have been reduced to cinders ages ago."

Comments

Nature paper

[petaflop]

Nature paper here. Interesting quote:

For comparison, WASP-18b's infall timescale is an order of magnitude shorter than that of the much-discussed OGLE-TR-56b6, 7 (assuming that Q is the same for both), and gives a current rate of period change of â"0.00073 (106/Q) s/yr. For low values of Q this would accumulate to a detectable change in transit epoch in less than a decade (for Q = 106 the transit time shifts by 28 s after 10 yr, which compares with a currently achievable timing accuracy of 5 s). Thus WASP-18b is a diagnostic planet, either (for a low Q) being an exceptionally rare object in which the tidal decay is directly measurable, or forcing a reappraisal to much higher Q values; either way it will help establish the dynamical ages of the class of hot-Jupiter planets. WASP-18 will also help constrain our understanding of stellar interiors, given that the Q value depends on the dissipation of interior waves excited by the tidal forcing.

So if the orbit is decaying, we'll be able to measure it in 10 years, otherwise there will be useful data to refine theories about tidal forces in the surfaces of stars.

Maybe it was a "normal" planet...

[Osvaldo Doederlein]

...formed one billion years ago, but originally much more distant from the star. But its orbit was not stable, approaching quickly (in astronomical time) to the star; and we're just lucky to have found it in the final stage of the death spiral. If this is the case, it may even be possible to watch the final spectacle in a timeframe reasonable for human scale (a few thousand years, perhaps centuries, or even less).

Wild speculation of course... but just to be safe, I'm immediately canceling all my plans of space vacations near the Wasp18 system. I never liked wasps anyway.