Changing Planet

Newly Discovered Planet Wobbles as It Spins

The unusual orbit of Kepler-413b around a pair of orange and red dwarf stars. Courtesy NASA, ESA, A. Feild (STScI)

A newly discovered planet wobbles as it spins, astronomers say, though it’s in no danger of falling down.

The planet, dubbed Kepler-413b, wobbles as it spins around on its north-south axis circling its stars. The wobbles have altered the planet’s tilt by as much as 30 degrees (the angle between the 12 o’clock and the 1 o’clock position on a timepiece) over the last 11 years, reports an astronomy team led by Veselin Kostov of the Space Telescope Science Institute in Baltimore.

Earth, by contrast, has spun on the same 23.5-degree tilt for at least 26,500 years.

Located some 2,300 light-years away in the constellation Cygnus, the Swan, the planet orbits a pair of stars once every 66 days. Its wobbling is so intense that it affects how we observe its orbit; astronomers detected its peculiar motion in data from NASA’s Kepler Space Telescope.

The Kepler telescope usually detects planets by spotting eclipses, or transits, of stars made by their orbiting worlds. Kepler-413b transited its stars, but in a wildly uneven pattern, which tipped off astronomers to its existence.

“Looking at the Kepler data over the course of 1,500 days, we saw three transits in the first 180 days—one transit every 66 days—then we had 800 days with no transits at all,” Kostov said in a statement. “After that, we saw five more transits in a row.”

The wobbles seen on Kepler-413b would induce wildly transient seasons on a planet such as Earth, but Kepler-413b is a gassy world some 65 times heavier than ours and is too hot to sustain life as we know it.

The study detailing the Kepler telescope observations of the planet’s wobble appears in the January 29 edition of the Astrophysical Journal.

  • Chris

    360/12=30 The angle between 12 and 1 is 30 deg. Between 11 and 1 is twice that.

  • Dan Vergano

    Hey, you are right, I was revolving the axis around the center in my head when I wrote that, doubling the wobble. Will fix the mistake, thanks for the note.

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