Since then profits warnings , public disputes with regulators , a stock market investigation into alleged improper disclosure practices and allegations of cronyism by sol Trujillo , the chief executive , have combined to produce one of the most turbulent periods in Telstra \' s history .
Planetary astronomer Michael Brown of the California Institute of Technology in Pasadena and postdoctoral scholar Chadwick Trujillo discovered the object in images taken June4 .