This article summarizes findings showing that the Spitzer telescope has observed the spectral signature of tryptophan in an extrasolar system.

This isn’t the first instance of amino acids found extra-terrestrially (previously found on asteroids), but is the first found outside our solar system. Tryptophan has a very strong and very clear spectral signature (it is ubiquitously used in life sciences for example).

doi: https://dx.doi.org/10.1093/mnras/stad1535