Adds two datasets sourced from NASA’s Exoplanet Archive (retrieved via the REXoplanets package):
planets: one row per confirmed exoplanet from the Planetary Systems Composite Parameters (pscomppars) table, with host-star parameters merged in.
stars: reference-level stellar host parameters (stellarhosts table) — many rows per star, one per published parameter solution.
Column names have been simplified for classroom use and units baked into names where ambiguous. Original NASA short names are preserved in the data dictionaries shipped under inst/extdata/.
