NASA's WISE survey: No planet X...

[MargaritaMc]

NASA's WISE Survey Finds Thousands of New Stars, But No 'Planet X'

March 07, 2014

After searching hundreds of millions of objects across our sky, NASA's Wide-Field Infrared Survey Explorer (WISE) has turned up no evidence of the hypothesized celestial body in our solar system commonly dubbed "Planet X."

Researchers previously had theorized about the existence of this large, but unseen celestial body, suspected to lie somewhere beyond the orbit of Pluto. In addition to "Planet X," the body had garnered other nicknames, including "Nemesis" and "Tyche."

This recent study, which involved an examination of WISE data covering the entire sky in infrared light, found no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (au), and no object larger than Jupiter exists out to 26,000 au. One astronomical unit equals 93 million miles. Earth is 1 au, and Pluto about 40 au, from the sun.

...
But searches of the WISE catalog are not coming up empty. A second study reveals several thousand new residents in our sun's "backyard," consisting of stars and cool bodies called brown dwarfs.

"Neighboring star systems that have been hiding in plain sight just jump out in the WISE data," said Ned Wright of the University of California, Los Angeles, the principal investigator of the mission.

More at:
http://www.jpl.nasa.gov/wise/newsfeatur ... e=2014-075

[BDanielMayfield]

This topic relates to my question about how many planets exist.
http://asterisk.apod.com/viewtopic.php?f=8&t=32706

After all, if we can’t even be sure how many planets there are in our own backyard, how would we ever be able to come up with a reasonable estimate for planetary numbers in the whole galaxy or the observable part of the universe? So I dug a little deeper as I was curious about the limits of what this WISE study has ruled out as far as the potential for less massive planets that might still be lurking in the depths of our solar system. I found this wonderful graphic from JPL that charts what can and cannot be detected by WISE.
http://www.jpl.nasa.gov/spaceimages/det ... d=pia17990

Yes, the existence of a large as yet to be detected planet does seem to be ruled out by WISE, but small planets, and that depends critically on what is meant by “small planet,” could still be out there. But this study goes far in telling us that the main planetary family of our system is basically complete.

Bruce