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Can We Measure an Exoplanet’s Orbital Decay?

-- | March 21, 2013

Question:  Is it possible for a planet of an established solar system orbiting a star to be in a decaying orbit and if so how do astronomers confirm this as the star and its solar system can be vast numbers of light years away?  — David

Answer:  Yes, it is possible to see an exoplanet’s orbit decaying, but this would require measurements of its orbit over a period long enough to measure the decay, or change, in its orbital parameters (i.e. the orbital period).  Also, this would be a measurement referenced to the state of this planet’s orbit when the light we receive was emitted by the planet, which might be many light years away.

Jeff Mangum