Hansen - Petersen
HANSEN is a common Danish surname derived from the name of an ancestor, 'the son of Hans'.
PETERSEN is also a common Danish surname derived from the name of an ancestor, 'the son of Peter'.
Note: Danish surnames tended to be Patronymic, a name derived from the personal name of the father or to the father’s occupation. This means the surnames tend to change with each generation and with the gender of the child ('sen' for son of, 'datter' for daughter of). This means that someone is not likely to be related to someone else from Denmark with the same surname. This surname system gradually ended in the mid 1800s (depending on the family).