No, it is not an adverb. Planetarium is a noun, an astronomical theater.
The Adler Planetarium was built in 1930 and is the oldest planetarium in existence today.
Birla planetarium
Alfa Planetarium was created in 1978.
Jawahar Planetarium was created in 1979.
Planetarium - Burma - was created in 1968.
Planetarium of Nantes was created in 1980.
Minnesota Planetarium was created in 2003.
McLaughlin Planetarium was created in 1968.
McLaughlin Planetarium ended in 1995.
Hayden Planetarium was created in 1935.
Eisinga Planetarium was created in 1781.
Montreal Planetarium was created in 1966.