  To explain the unusual distribution of Kuiper Belt objects, several authors
have advocated the existence of a super-Earth planet in the outer solar system.
It has recently been proposed that a 10 M$_{\oplus}$ object with an orbit of
700 AU semi major axis and 0.6 eccentricity can explain the observed
distribution of Kuiper Belt objects around Sedna. Here we use the INPOP
planetary ephemerides model as a sensor for testing for an additional body in
the solar system. We test the possibility of adding the proposed planet without
increasing the residuals of the planetary ephemerides, fitted over the whole
INPOP planetary data sample. We demonstrate that the presence of such an object
is not compatible with the most sensitive data set, the Cassini radio ranging
data, if its true anomaly is in the intervals $[-130^\circ:-100^\circ]$ or
$[-65^\circ : 85^\circ]$. Moreover, we find that the addition of this object
can reduce the Cassini residuals, with a most probable position given by a true
anomaly $v = {117.8^\circ}^{ + 11^\circ}_{ - 10^\circ} $.
