A team made of researchers of the IPAG1 and the IRAP2 has announced the presence of formamide in the gas surrounding IRAS 16293-2422, a star similar to our Sun, in formation in the nebula of Rho Ophiuchi3 . This discovery, published on January 16, 2013 in the International Astrophysical Journal Letter, could be an important step in the understanding of the origin of life on Earth after the formation of our solar system.
Recent biochemical studies suggest that the molecule of formamide, NH2CHO, is the common starting point of the prebiotic synthesis of metabolic as well as genetic molecules : amino acids, sugars, nucleic acids, carboxylic acids … In this context, it is possible that the discovery of formamide in the environment of a sun-like star in formation, marks a new step in our understanding of the development of the chemical complexity in the history of the Sun and the Solar System.
Hence the importance of the detection made by researchers from Grenoble and Toulouse of 39 lines of formamide in the radio spectrum emitted by the gas which surrounds a star similar to our Sun, IRAS 16293-2422, in the process of forming in the nebula of Rho Ophiuchi. Their observations were obtained with the new spectral receptors installed on the 30m telescope of the IRAM4, located at about 3000m in the Sierra Nevada in southern Spain.
Thanks to its proximity to Earth (400 light-years), the IRAS 16293-2422 source is easy to observe. For nearly 30 years, it is considered as the prototype of solar-type stars in formation, and has therefore given rise to many works of observation and modeling, especially with the instruments of the IRAM, the Herschel satellite and most recently with the large international interferometer ALMA . Thanks to previous studies , which enable to know the size of the cocoon of gas responsible for the observed emission, it has been possible to deduce the abundance of the molecule by comparing the observed rays to those predicted by a model of emission of the molecule.
So far, formamide was detected in only two objects located outside the solar system, the clouds of Orion and of Sagittarius B2. These two sources are well known to form massive stars which emit ultraviolet and X radiations; chemistry models attributed the mechanisms of formation of interstellar formamide to the presence of these energetic radiations in a very different environment than the one that has known the Sun during its formation. That the formamide appears as abundant in the vicinity of IRAS 16293-2422 as in the heavily irradiated regions therefore leads to revise the scenario of formation of of this molecule.
Even more interesting, a comparison of the abundances of formamide and water, a molecule essential to life, in the environment of IRAS 16293-2422 with the abundances measured in the halo of the Hale-Bopp comet, provides similar ratios in the two sources, which may indicate a relationship between the chemistry that is currently taking place in the environment of IRAS 16293-2422 and that that experienced our solar system during its formation.
- Institut de planétologie et d’astrophysique de Grenoble (IPAG-Université Joseph Fourier/CNRS-OSUG)
- Institut de recherche en astrophysique et planétologie (IRAP-Université Paul Sabatier Toulouse III/CNRS-OMP)
- Nebula located in the constellation Ophiuchus
- Institut de RadioAstronomie Millimétrique (IRAM-CNRS)
- Publication scientifique : Detection of Formamide, the simplest but crucial amide in a solar type protostar, C. Kahane et al. 2013 ApJ 763 L38
- Emmanuel Caux, IRAP-OMP (CNRS/Université Paul Sabatier-Toulouse III), email@example.com, 05 61 55 66 89