Lowercase the e and don’t hyphenate (Note: this is an exception to AP style.)
Emeritus is an honorary rank bestowed on retired University faculty. Always use the construction “professor emeritus” NOT “emeritus professor.” The title should be in lowercase; avoid constructions with the title before the name. Emeritus and emeriti are the preferred singular and plural terms of professors of any gender. The feminine term emerita may be used given the preference of the subject.