Am I obligated to visit my father who lives far away from us after he married another woman and left my mother and siblings?

Your father must be just between his two wives, otherwise he will be subject to punishment on the Day of Resurrection. Your mother must obey him in what is right and not sever ties with him if she is still his wife. However, if he divorces her, she owes him no right. The children must visit their father and obey him in what is right, and they are not obligated to obey their mother if she commands them to sever ties with their father.