Remove the mappedBy attribute from the OneToMany annotation and add the following annotation.
@JoinColumn(name="Heat")
mappedBy is not supported when using OrderColumn unless you want to set the property yourself.
If you do want to set the property yourself you would have to add the following to team and increment the index yourself.
@Column(name="Heat_index")
public int getHeatIndex() {
return heatIndex;
}