Kepler Discovers 'Phantom' Exoplanet 78
astroengine writes "The Kepler space telescope has spotted an extra-solar planet with a very odd orbit. Sometimes Kepler-19b slows down by five minutes during its 9-day orbit. Other times it speeds up by five minutes. Johannes Kelper's laws of orbital dynamics never said a celestial body can arbitrarily speed up and slow down; another planetary body must therefore be gravitationally acting on Kepler-19b. Enter Kepler-19c, a world that hasn't been observed, but its gravitational effects have. This is an unprecedented discovery, one that could potentially be used in multi-planetary star systems to discover more 'phantom' worlds that would have otherwise gone unnoticed."
Not 'unprecedented' (Score:3, Informative)
This is an unprecedented discovery
Er, no. Neptune [wikipedia.org] and Pluto [wikipedia.org] were both discovered because of the perturbations they caused of the orbit of Uranus.
Re:Unprecedented? (Score:2, Informative)
From TFA:
So that's the exact criterion that makes it unprecedented.
Re:Not 'unprecedented' (Score:4, Informative)
They aren't exoplanets, and hence not a precedent.
Binary planet? (Score:4, Informative)
+/- 5 minutes in a 9 day orbit is a huge variation. This almost has to be a binary planet system, or planet with a massive moon, or something similar. Enough gravitational force to slow or speed up a planet large enough that we can detect it by transit dimming of it's star 650 LY from Earth, that's either a really light planet, or it's got a massive companion orbiting it. The other possibility is that there is a dark star (white/brown dwarf) orbiting the same star, but we should be able to detect that wobble via doppler shift, so the companion moon/planet seems more likely.
Re:Binary planet? (Score:4, Informative)