The largest piece of Mars ever found on Earth was sold for just over $5 million at an auction of rare geological and archaeological objects in New York on Wednesday, while a juvenile dinosaur skeleton went for more than $30 million.

The newfound exoplanet, called Kepler-139f, is a gigantic world roughly twice the mass of Neptune and 35 times the mass of Earth, and it takes 355 days to orbit its star, astronomers reported in a study published May 2 in The Astrophysical Journal Letters. Despite its giant size, Kepler-139f had evaded detection.