Hidden Planet Found Orbiting Distant Star WIth Aid Of Kepler Space Telescope

By: Clara Moskowitz
Published: 05/10/2012 02:09 PM EDT on SPACE.com

Detective astronomers have discovered at least one unseen alien planet, and possibly another, around a distant star by observing the odd behavior of a planet already known to orbit the same star.

The newfound planet has about the mass of Saturn and orbits its host star once every 57 days. It was revealed by its gravitational effects on the previously known planet around the parent star KOI-872. The find is an apparent validation of what scientists call the transit timing variation method of finding extrasolar planets.

The idea of looking for oddities in a main planet's transit of its star to search for other planets was suggested in 2005, but "this is the first occasion where there is great confidence that the method works," said astronomer David Nesvorný of the Southwest Research Institute in Boulder, Colo., who led the new study.

In fact, when the researchers looked in more detail at the system, they found signs of yet another planet, one only a bit larger than our own world. This "super-Earth" is likely circling very close to the star with an orbital period of 6.8 days.

Here's how the alien planet detective story played out:

The first look at data from NASA's planet-hunting telescope Kepler had identified only one planet around the star KOI-872. But a closer inspection by scientists outside the Kepler team revealed telltale signs of an extra planet.

As part of its systematic search for alien planets, Kepler looks for stars whose brightness dims periodically — a signal that something, presumably a planet, is passing in front of it and blocking its light. The Kepler team identified a light dip in KOI-872 (KOI stands for "Kepler Object of Interest") and attributed it to a planet that orbited the star every 34 days. However, that timing appeared to vary by a few hours.

"The planet should show transits equally spaced, which is not the case," Nesvorný said. "Sometimes the transit is two hours late, sometimes two hours early."

Using a computer model, Nesvorný and his colleagues concluded that the most likely explanation for the timing variations was the presence of another planet in the system, the Saturn-mass world. Their calculations suggested a likelihood greater than 99 percent that this mystery planet exists. [Gallery: A World of Kepler Planets]

Nesvorný and his team are now combing through the wealth of Kepler data for signs of exomoons — moons orbiting alien planets. So far none has been found.

"It mainly depends on if you can have really large moons, because if the moon is small, it wouldn't change transits too much," Nesvorný said. "At some point the first exomoon will be discovered. My guess is it will happen within a few years from now."

Scientists analyzed Kepler telescope data and identified KOI-872 as a stellar system where measured transits of a planet orbiting the star show large time variations (the shifting bumps in image).

After the Kepler team runs its main analysis of data, it releases the data publicly to any scientists who want to study it.

"This is an enormous amount of data, so there's no way the Kepler team would have time to look at everything," Nesvorný said. "I think there are many more additional gems waiting to be discovered in the data set, either by the Kepler team or by scientists not related to Kepler."

The new discovery is detailed in a paper published in the May 11 issue of the journal Science.

You can follow SPACE.com assistant managing editor Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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Comments

[Riverman]

01:49 PM on 05/14/2012

What a species, humans are exploring the stars and calculating their way through hyper dimensional space and grasping at what may just be a multi universe. On the other hand we humans also spend tons of time refining ways to fear and hate our fellow humans. Often this involves belief systems based on magical creatures and entities. We are literally all over the place.

[roc-o-rama]

01:08 PM on 05/14/2012

I can't wait for the James Webb Space telescope to be completed it will own help further our understanding of our universe where Kepler left off. I just wish we could divert funds from the MIC to our Space program that would be money well spent as opposed to another state of the art tank or fighter jet.

[LMPE]

05:36 PM on 05/13/2012

The transit timing variations look like a conga line.

[Riverman]

01:53 PM on 05/14/2012

When I first looked at it I didn't envision swinging hips but now I can't see it any other way. Thanks

[SavageLeto]

05:30 PM on 05/13/2012

I find it fascinating that Kepler shows us how many of these fairly massive planets are out there almost kissing their stars they are so close.

It really puts a dent into accretion disk formation of solar systems to me.

[mbkeefer]

08:04 PM on 05/11/2012

Interesting video. Did not know we had found so many M class planets around red dwarf stars so soon. Should we ever get around the light limit, there is a lot of real estate out there to develope and settle.

[BannedInBoston]

10:19 PM on 05/13/2012

There are probably even a fair number that are reachable at sub-light speeds (with a little patience). They just haven't been discovered yet. It is interesting that the most "earthlike" ones all orbit so-called red dwarfs. That's got to have weird effects on habitability....

[mbkeefer]

11:51 PM on 05/13/2012

With red dwarfs the habital zone is close in and the orbital period in short. You need three or four orbits of data to find the planet. It would take 3 or 4 years to find Earth and Keplar has not been up there that long.
All those planets are either tide locked (one side always facing the star). That leaves only a small band with habital climate. Or they are in a resonace like Mercury and the days will last some multiple of the orbital period. Going to be rough, but better than being on a tide locked world.

[Jarrod Putnam]

02:12 PM on 05/11/2012

Who would have thought 50 years ago that we would be finding planets to easily, and at such a high rate. Can't wait until they get buffed up Hubble to actually see the planets like we see galaxies.

[BannedInBoston]

10:22 PM on 05/13/2012

I seem to recall as late as the early eighties, many scientists were expressing strong doubts that we would ever be able to observe any exoplanets at all....