New Oxygen Isotope Discovered!

 A newly discovered oxygen isotope is confounding all preconceptions about how it should behave.

It's oxygen-28, with the most neutrons ever seen in an oxygen atom's nucleus. Despite the fact that scientists believe it should be stable, it decays swiftly, throwing into doubt what we thought we knew about "magic" quantities of particles in an atom's nucleus.

An atom's nucleus includes subatomic particles called nucleons, which are made up of protons and neutrons.

The amount of protons in an element determines its atomic number, although the number of neutrons might vary. Isotopes are elements with varying neutron numbers; for example, oxygen contains 8 protons but different neutron numbers.

The most neutrons ever measured were 18, in the oxygen isotope oxygen-26 (8 protons + 18 neutrons = 26 nucleons). Now, a team led by nuclear physicist Yosuke Kondo of Japan's Tokyo Institute of Technology has discovered two previously unknown oxygen isotopes, oxygen-27 and oxygen-28, containing 19 and 20 neutrons, respectively. 

The research was carried out at the RIKEN Radioactive Isotope Beam Factory, a cyclotron accelerator facility intended to generate unstable isotopes. To begin, the researchers fired a beam of calcium-48 isotopes at a beryllium target to make lighter atoms such as fluorine-29, a fluorine isotope with 9 protons and 20 neutrons. 

This fluorine-29 was then separated and smashed with a liquid hydrogen target in an effort to make oxygen-28 by knocking off a proton.