Abstract
We employed data from the Spitzer Space Telescope to investigate the presence of the aromatic amino acids tyrosine and phenylalanine in the interstellar gas of the young star cluster IC 348. Our analysis revealed emission lines in the observed spectrum that closely matched the strongest mid-infrared laboratory bands associated with tyrosine and phenylalanine in terms of wavelength and intensity. Through flux measurements, we estimated column densities along the line of sight toward the core of IC 348, ranging from 0.8-1.0 × 10(11) cm(-2). Additionally, these emission lines were evident in the combined spectra of more than 30 interstellar locations spanning various unrelated star-forming regions observed by Spitzer, indicating a widespread distribution of the molecules responsible for the emission throughout interstellar space. Prospective endeavors employing high spectral resolution mid-infrared searches for proteinogenic amino acids in protostars, protoplanetary disks, and the interstellar medium will play a pivotal role in elucidating the external origins of meteoritic amino acids and understanding the prebiotic conditions that laid the groundwork for life on early Earth.