Coupling capacitor (for power-line carrier). Style 2.
The asterisk is not part of the symbol.
If specific identification is desired, the asterisk is to be replaced by one of the following letter combinations:

COM Carrier communication
LC Carrier load control
REL Carrier relaying
SUP Carrier supervisory
TLM Carrier telemetering
TT Carrier transferred trip
Derivative from this file 
(in English) (1993)  315-1975 - IEEE Standard American National Standard Canadian Standard Graphic Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters), IEEE, p. 27  DOI:  10.1109/IEEESTD.1993.93397. ISBN:  0738109479.
Michel Bakni