![\"Hydrocarbons](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14540e-IRAS-07251-0248.jpg\")
<\/a><\/p>\nHydrocarbons play a key role in shaping the chemistry of the interstellar medium, but their enrichment and relation with carbonaceous grains and polycyclic aromatic hydrocarbons still lack clear observational constraints. Garc\u00eda-Bernete et al. report on the Webb infrared observations of the local ultra-luminous infrared galaxy (ULIRG) IRAS 07251-0248, which revealed the extragalactic detection of small gas-phase hydrocarbons. Image credit: Garc\u00eda-Bernete et al., doi: 10.1038\/s41550-025-02750-0.<\/p>\n
The nucleus of IRAS 07251-0248<\/a> (also known as 2MASS J07273756-0254540) is hidden behind vast amounts of gas and dust.<\/p>\n This material absorbs most of the radiation emitted by the central supermassive black hole, making it extremely difficult to study with conventional telescopes.<\/p>\n However, the infrared wavelength range penetrates the dust and provides unique information about these regions, revealing the dominant chemical processes in this extremely dusty nucleus.<\/p>\n Dr. Ismael Garc\u00eda Bernete and his colleagues used spectroscopic observations from Webb\u2019s NIRSpec and MIRI instruments covering the 3-28 micron wavelength range.<\/p>\n These observations allow the detection of chemical signatures from gas-phase molecules, as well as features from ices and dust grains.<\/p>\n Thanks to these data, the astronomers were able to characterize the abundance and temperature of numerous chemical species in the nucleus of this buried galaxy.<\/p>\n The observations revealed an extraordinarily rich inventory of small organic molecules, including benzene, methane, acetylene, diacetylene, and triacetylene, and, detected for the first time outside the Milky Way, the methyl radical<\/a>.<\/p>\n In addition to gas-phase molecules, a large abundance of solid molecular materials was found, such as carbonaceous grains and water ices.<\/p>\n \u201cWe found an unexpected chemical complexity, with abundances far higher than predicted by current theoretical models,\u201d said Dr. Garc\u00eda Bernete, an astronomer at the Centro de Astrobiolog\u00eda.<\/p>\n \u201cThis indicates that there must be a continuous source of carbon in these galactic nuclei fueling this rich chemical network.\u201d<\/p>\n \u201cThese molecules could play a key role as fundamental building blocks for complex organic chemistry, of interest for processes relevant to life.\u201d<\/p>\n \u201cAlthough small organic molecules are not found in living cells, they could play a vital role in prebiotic chemistry representing an important step towards the formation of amino acids and nucleotides,\u201d said University of Oxford\u2019s Professor Dimitra Rigopoulou.<\/p>\n