It can be made in an electric discharge, and was the first noble gas molecular ion to be found in interstellar space.

[5] Artificial ArH+ made from earthly argon contains mostly the isotope 40Ar rather than the cosmically abundant 36Ar.

[10] Brault and Davis were the first to detect the molecule using infrared spectroscopy to observe vibration–rotation bands.

A 15.8 eV to a repulsive A1Σ+ state is at a shorter wavelength than the Lyman limit, and so there are very few photons around to do this in space.

[6] Possible the energy required to excite the ions so that then can emit comes from collisions with electrons or hydrogen molecules.

[5] Two isotopologs of argonium 36ArH+ and 38ArH+ are known to be in a distant unnamed galaxy with a redshift of z = 0.88582 (7.5 billion light years away) which is on the line of sight to the blazar PKS 1830−211.

[4] Electron neutralization and destruction of argonium outcompletes the formation rate in space if the H2 concentration is below 1 in 10−4.

[11] Using the McMath solar Fourier transform spectrometer at Kitt Peak National Observatory, James W. Brault and Sumner P. Davis observed ArH+ vibration-rotation infrared lines for the first time.