Methyl acetylene (CH₃CCH) was reported by Buhl and Snyder in the early 1970s. They reported a single rotational line in Sgr B2 observed with the 36-foot telescope at Kitt Peak. Subsequent work by Hollis et al. in 1981 and Kuiper et al. in 1984 identified sufficient additional lines to confirm the initial detection. Methyl acetylene has also been observed in the atmospheres of Jupiter, Saturn, and Uranus, all via IR spectroscopy. The Jupiter and Saturn detections were made with the Infrared Space Observatory, while the 2006 Uranus detection was made with the Spitzer Space Telescope. Finally, methyl acetylene has also been observed in the atmosphere of Titan.

Methyl acetylene or propyne is a very reactive and flammable gas at standard temperature and pressure. As a symmetric top molecule, it is useful in astronomy as a means of ascertaining temperature.