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
Hayden Planetarium was created in 1935.
Eisinga Planetarium was created in 1781.
Expensive Planetarium was created in 1962.
Expensive Planetarium happened in 1962.
London Planetarium ended in 2006.
London Planetarium was created in 1958.
Alfa Planetarium was created in 1978.
Jawahar Planetarium was created in 1979.
McLaughlin Planetarium was created in 1968.
McLaughlin Planetarium ended in 1995.