A Nitrogen-9 isotope was recently created and spotted by researchers, raising questions about the classifications of nuclei
The nucleus of isotope nitrogen-9 has just been created and spotted by a group of researchers from Michigan State University, as reported in the Oct. 27 Physical Review Letters. This has previously been near impossible as the fleeting nature of the atom results in its minimal existence of one billionth of a nanosecond, due to its extreme imbalance of nucleons.
Comprising seven protons, this newly spotted isotope is unmistakably a nitrogen atom. However, only two neutrons exist in the nucleus while a balanced atom has an equal number of protons and neutrons, held together with “the strong force”. This point where the number of neutrons is past the stability point, especially when the number of protons is in excess due to its positive charge, is known as “the drip line” - the theoretical limit of nuclear stability.
“People talk about the drip line as something like the end of the existence of nuclei,” Marek Płoszajczak, a nuclear physicist at the Grand Accélérateur National d’Ions Lourds in Caen, France, explains. To achieve stability, atoms usually undergo radioactive decay of the extra protons or neutrons. In this case, it is the five extra protons that will be released in the process of the decay.
The discovery pushes the limit of what was previously thought possible, as atoms with only four extra protons past the drip line had been spotted. Questions regarding this have also been raised about how a nucleus should be identified as one, as nitrogen-9 lasts just 10 times as long as the minimum cutoff for the existence of an atom to be considered a nucleus, for a total of 10-22seconds. Additionally, it introduces an interesting exploratory field regarding the life length of a nucleus past the drip line, or as Płoszajczak voices: “These experiments show that the life of the nucleus extends far beyond the drip line,” and “should give them a “push” to improve their models of nuclei beyond the drip line, which are still rather limited,” as reported by ScienceNews.