The icy satellites around Jupiter are considered to have formed in a circumplanetary disk .
While previous models focused on the formation of satellites starting from satellitesimals , the question of how satellitesimals form from smaller dust particles has not been addressed so far .
In this work , we study the possibility that satellitesimals form in situ in a circumplanetary disk .
We calculate the radial distribution of the surface density and representative size of icy dust particles that grow by colliding with each other and drift toward the central planet in a steady circumplanetary disk with a continuous supply of gas and dust from the parent protoplanetary disk .
The radial drift barrier is overcome if the ratio of the dust to gas accretion rates onto the circumplanetary disk , \dot { M } _ { \mathrm { d } } / \dot { M } _ { \mathrm { g } } , is high and the strength of turbulence , \alpha , is not too low .
The collision velocity is lower than the critical velocity of fragmentation when \alpha is low .
Taken together , we find that the conditions for satellitesimal formation via dust coagulation are given by \dot { M } _ { \mathrm { d } } / \dot { M } _ { \mathrm { g } } \geq 1 and 10 ^ { -4 } \leq \alpha < 10 ^ { -2 } .
The former condition is generally difficult to achieve , suggesting that the in-situ satellitesimal formation via particle sticking is viable only under an extreme condition .
We also show that neither satellitesimal formation via the collisional growth of porous aggregates nor via streaming instability is viable as long as \dot { M } _ { \mathrm { d } } / \dot { M } _ { \mathrm { g } } is low .