Kepler Discovers a Very Wobbly Planet with Weird Seasons

[gwillybj]

Kepler Discovers a Very Wobbly Planet with Weird Seasons

The planet – Kepler-413b – wobbles wildly on its spin axis. Its season changes are wild and fast.


This illustration shows the unusual orbit of planet Kepler-413b around a close pair of orange and red dwarf stars. The planet’s 66-day orbit is tilted 2.5 degrees with respect to the plane of the binary star’s orbit. The orbit of the planet wobbles around the central stars over 11 yearsImage Credit: NASA, ESA, A. Feild (STScI)

Imagine living on a planet with seasons so erratic you would hardly know whether to wear Bermuda shorts or a heavy overcoat. That is the situation on a weird, wobbly world found by NASA’s planet-hunting Kepler space telescope.

The planet, designated Kepler-413b, precesses, or wobbles, wildly on its spin axis, much like a child’s top. The tilt of the planet’s spin axis can vary by as much as 30 degrees over 11 years, leading to rapid and erratic changes in seasons. In contrast, Earth’s rotational precession is a relatively tame 23.5 degrees over 26,000 years. Researchers are amazed that this far-off planet is precessing on a human timescale.

Kepler 413-b is located 2,300 light-years away in the constellation Cygnus. It circles a close pair of orange and red dwarf stars every 66 days. The planet’s orbit around the binary stars appears to wobble, too, because the plane of its orbit is tilted 2.5 degrees with respect to the plane of the star pair’s orbit. As seen from Earth, the wobbling orbit moves up and down continuously.

Kepler finds planets by measuring the dimming of starlight when a planet passes in front of its parent sun–or, in this case, suns because the planet circles a pair of stars. Normally, planets transit like clockwork. Astronomers using Kepler discovered the wobbling when they found an unusual pattern of transiting for Kepler-413b.

“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. After that, we saw five more transits in a row,” said Veselin Kostov, the principal investigator on the observation. Kostov is affiliated with the Space Telescope Science Institute and Johns Hopkins University in Baltimore, Md. “[The next transit visible from Earth is not predicted to occur until 2020.]”

Astronomers are still trying to explain why this planet is out of alignment with its stars. There could be other planetary bodies in the system that tilted the orbit. Or, it could be that a third star nearby that is a visual companion may actually be gravitationally bound to the system and exerting an influence.

“Presumably there are planets out there like this one that we’re not seeing because we’re in the unfavorable period,” said Peter McCullough, a team member with the Space Telescope Science Institute and Johns Hopkins University. “And that’s one of the things that Veselin is researching: Is there a silent majority of things that we’re not seeing?”

Even with its changing seasons, Kepler-413b is too warm for life as we know it. Because it orbits so close to the stars, its temperatures are too high for liquid water to exist, making it inhabitable. It also is a super Neptune — a giant gas planet with a mass about 65 times that of Earth — so there is no surface on which to stand.

Via NASA: http://science.nasa.gov/science-news/science-at-nasa/2014/04feb_wobble/

http://earthsky.org/space/kepler-discovers-a-very-wobbly-planet-with-erratic-seasons

[Geo]

65 Earth masses? That one is a borderline Saturn then (about 100 EM's).

And if (an)other planet(s) in this system is the cause of the wobble, they must be real heavies...

[gwillybj]

I'm just wondering if its inhabitants get dizzy. 

[Geo]

I'm sure (if they existed) they'd believe in a fickle pantheon.

[gwillybj]

What was that movie?

"The Gods Must Be Crazy"

http://www.imdb.com/title/tt0080801/

[Geo]

I especially liked the Great White Hunter (well, guide actually) in that movie. And his complexicies.

[Buster's Uncle]

Wobbly Alien Planet with Wild Seasons Found by NASA Telescope
SPACE.com
by Megan Gannon, News Editor  8 hours ago



This illustration shows the unusual orbit of newly discovered planet Kepler-413b. The alien world circles around a close pair of orange and red dwarf stars and the tilt of its spin axis can vary by as much as 30 degrees over 11 years



Astronomers have discovered an alien planet that wobbles at such a dizzying rate that its seasons must fluctuate wildly.

Throughout all of the planet's fast-changing seasons, however, no forecast would be friendly to humans. The warm planet is a gassy super-Neptune that orbits too close to its two parent stars to be in its system's "habitable zone," the region where temperatures would allow liquid water, and perhaps life as we know it, to exist.

The faraway world, which lies 2,300 light-years away in the constellation Cygnus, was discovered by NASA's planet-hunting Kepler space telescope. Dubbed Kepler-413b, the planet orbits a pair of orange and red dwarf stars every 66 days.

Kepler was designed to detect exoplanets by noticing the dips in brightness caused when these worlds transit, or cross in front of, their parent stars. Normally these transits occur in a regular pattern, but Kepler-413b behaved strangely.

"What we see in the Kepler data over 1,500 days is three transits in the first 180 days (one transit every 66 days), then we had 800 days with no transits at all," study lead investigator Veselin Kostov, of the Space Telescope Science Institute and Johns Hopkins University, said in a statement. "After that, we saw five more transits in a row."

Kostov and colleagues concluded that the planet's wobble must be causing it to move up or down relative to our view, so much so that it sometimes doesn't appear to cross in front of its parent stars. (A NASA statement compared the planet's motions to a child's spinning top on the rim of a wobbling bicycle wheel rotating on its side.)

The scientists determined that the planet's axial tilt can vary by as much as 30 degrees over 11 years,. For comparison, Earth's tilt has shifted 23.5 degrees over 26,000 years. The researchers say it's amazing that this planet is wobbling, or precessesing, so much on a human time scale, and they say it's possible that there are other planets like Kepler-413b awaiting discovery.

"Presumably there are planets out there like this one that we're not seeing because we're in the unfavorable period," Peter McCullough, a team member from STScI and JHU, said in a statement.

Kostov and colleagues are still investigating what causes the extreme wobble of the gas planet, which has a mass about 65 times that of Earth. They say Kepler-413b's orbit may have been tilted by other planets in the system or by a nearby star exerting gravitational influence.

The research was detailed in the Jan. 29 issue of The Astrophysical Journal.

Kepler was disabled last year after suffering a major failure, but engineers are have developed a possible new mission that would use the spacecraft in its compromised state. The $600 million Kepler mission launched in 2009 and has detected more than 3,500 exoplanet candidates to date.


http://news.yahoo.com/wobbly-alien-planet-wild-seasons-found-nasa-telescope-114446808.html

[Geo]

Wait a sec. Earth's tilt changes 23 degrees over 26,000 years? Are they telling us Earth's tilt goes to zero and back? Or 23 to 46 degrees?
AFAIK, the variance of Earth's tilt is roughly 2.3 degrees over the course of 26,000 years.

[gwillybj]

Yes, Earth's tilt has changed from zero to 23.5 degrees. The seasons have not always been so clearly defined. There was a time when the temperate zone reached from pole to pole and woolly mammoths ate daisies.

[Geo]

Not according to the stuff I read. Earth's axial tilt should only vary between 22 and 24,3 degrees over a timespan of 41,000 years. So I did mix precession with obliquity.
The 26,000 year timespan is the precession cycle, it doesn't change the physical angle of Earth's tilt.