Can WISE Find the Hypothetical Planet 'Tyche'?

WISE. Artist rendering. Credit:NASA
In November 2010, the scientific journal Icarus published a paper by astrophysicists John Matese and Daniel Whitmire, who proposed the existence of a binary companion to our sun, larger than Jupiter, in the long-hypothesized "Oort cloud" -- a faraway repository of small icy bodies at the edge of our solar system. The researchers use the name "Tyche" for the hypothetical planet.

Their paper argues that evidence for the planet would have been recorded by the Wide-field Infrared Survey Explorer (WISE).

WISE is a NASA mission, launched in December 2009, which scanned the entire celestial sky at four infrared wavelengths about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets relatively close to Earth.

WISE Catches Comet 65P/Gunn
credit: NASA/JPL
Following its successful survey, WISE was put into hibernation in February 2011.
Analysis of WISE data continues. A preliminary public release of the first 14 weeks of data is planned for April 2011, and the final release of the full survey is planned for March 2012.

It will take time to be able to analyse all data from WISE, and, to confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not.

The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.

It is likely but not a foregone conclusion that WISE could confirm whether or not Tyche exists. Since WISE surveyed the whole sky once, then covered the entire sky again in two of its infrared bands six months later, WISE would see a change in the apparent position of a large planet body in the Oort cloud over the six-month period.

The two bands used in the second sky coverage were designed to identify very small, cold stars (or brown dwarfs) -- which are much like planets larger than Jupiter, as Tyche is hypothesized to be. Tyche would be too cold and faint for a visible light telescope to identify. Sensitive infrared telescopes as WISE could pick up the glow from such an object, if they looked in the right direction.


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