Al26Mg26

Al26Mg26 is a hypothetical diatomic isotopologue consisting of one Aluminum-26 nucleus bonded to one Magnesium-26 nucleus. As an isotopologue, it would differ from the more common AlMg species by the specific neutron configurations of its constituent nuclei, and its physical properties would be subtly altered by the isotopic masses.

Aluminum-26 is a radioactive nuclide with a mean lifetime of about 0.71 million years. It decays to Magnesium-26 through beta-plus decay (and electron capture), emitting characteristic gamma rays, the most notable being a 1.809 MeV line. The presence of Al-26 in astrophysical environments is a key tracer of recent nucleosynthesis in regions such as massive-star winds, supernovae, and novae, and its decay products contribute to the chemical evolution of the interstellar medium.

If Al26Mg26 exists, it would be a heteronuclear diatomic molecule whose rotational and vibrational spectra would be shifted relative to non-radioactive analogs due to the heavier isotopes. In principle, such a molecule could form in high-temperature, high-density stellar ejecta or in circumstellar environments where isotopic labeling occurs. Its lifetime would be governed by the Al-26 decay, after which the molecule would transform into Mg26Mg26 as the aluminum nucleus decays to magnesium.

Observationally, evidence for Al-26 comes from gamma-ray astronomy rather than molecular spectroscopy. Al26Mg26 remains a theoretical isotopologue; its detection would complement broader studies of Al-26 production, distribution, and nucleosynthetic yields in the galaxy. See also: aluminum-26, magnesium-26, isotopologues, gamma-ray astronomy.