Abstract

Complex organic molecules (COMs), which are the seeds of prebiotic material and precursors of amino acids and sugars, form in the icy mantles of circumstellar dust grains(1) but cannot be detected remotely unless they are heated and released to the gas phase. Around solar-mass stars, water and COMs only sublimate in the inner few au of the circumstellar disk(2), making them extremely difficult to spatially resolve and study. Sudden increases in the luminosity of the central star will quickly expand the sublimation front (the so-called snow line) to larger radii, as seen previously in the FU Ori outburst of the young star V883 Ori(3). Here, we take advantage of the rapid increase in disk temperature of V883 Ori to detect and analyse five different COMs-methanol, acetone, acetonitrile, acetaldehyde and methyl formate-in spatially resolved submillimetre observations. The abundances of COMs in the disk around V883 Ori are in reasonable agreement with cometary values4, suggesting that outbursting young stars can provide a special opportunity to study the ice composition of material directly related to planet formation.