The Atacama Cosmology Telescope: A search for Planet 9

Understand

We use Atacama Cosmology Telescope (ACT) observations at 98 GHz (2015--2019), 150 GHz (2013--2019) and 229 GHz (2017--2019) to perform a blind shift-and-stack search for Planet 9.

• The search explores distances from 300 AU to 2000 AU and velocities up to 6.3 arcmin per year, depending on the distance.
• For a 5 Earth-mass Planet 9 the detection limit varies from 325 AU to 625 AU, depending on the sky location.
• For a 10 Earth-mass planet the corresponding range is 425 AU to 775 AU.