The surname Asmus is a patronymic name derived from the German personal name Erasmus (which in turn was derived from the Latinized form of the Greek word "erasmos," meaning love), borne by an early Christian saint.  Generally, many of the family evolved the name to Rasmussen in Denmark. The suffix '-sen' is translatable as 'son of.'
^ Smith, Eldson Coles, New Dictionary of American Family Names New York: Harper & Row, 1956. Print
^ Filby, P. William, Meyer, Mary K., Passenger and immigration lists index : a guide to published arrival records of about 500,000 passengers who came to the United States and Canada in the seventeenth, eighteenth, and nineteenth centuries. 1982-1985 Cumulated Supplements in Four Volumes Detroit, Mich. : Gale Research Co., 1985, Print (ISBN 0-8103-1795-8)