A stellar corpse reveals the origin of radioactive molecules – AIM Digital

Using Alma and Noema, a team of astronomers realized the first definitive detection of a radioactive molecule in interstellar space. The radioactive part of the molecule is an isotope of aluminum. The observations reveal that the isotope was dispersed in space after the collision of two stars, leaving a remainder known as CK Vulpeculae. This is the first time that a direct observation of this element is made in a known source. This isotope had already been identified, but it came from the detection of gamma rays and its exact origin was unknown.

The team, led by Tomasz Kamiński (Center of Harvard astrophysics) Smithsonian, Cambridge, USA), used Alma (Atacama's large submillimeter / sub-millimeter group) and the Noema ensemble (expanded millimetric array) to detect a source radioactive isotope of aluminum-26. The fountain, known as CK Vulpeculae, was seen for the first time in 1670 and at that time, what the observers saw looked like a "new star", bright and red. Although initially visible to the naked eye, it quickly disappeared and powerful telescopes are now needed to see the remains of this fusion, a tenuous central star surrounded by a halo of incandescent material that in derives

348 years after the merger. The initial event will be observed, the remains of this explosive stellar melting led to the clear and convincing signature of a radioactive version of aluminum, known as aluminum – 26. It is the first unstable radioactive molecule definitely detected outside the solar system. Unstable isotopes have an excess of nuclear energy and, finally, disintegrate in a stable form.

"The first observation of this isotope in a stellar type object is also important in a broader context: that of the chemical evolution of the galaxy," says Kamiński. "This is the first time that the origin of the radioactive nuclide aluminum-26 is directly identified. "

Kamiński and his team detected the only spectral signature of molecules composed of aluminum-26 and fluorine (26AlF) in the remains that CK Vulpeculae, which is about 2000 light-years away from the Earth, when these molecules rotate and fall through space, they emit a distinctive luminous fingerprint at millimeter wavelengths, a process known as the name of rotational transition.The astronomers consider that it is the best way to detect molecules.

The observation of this particular isotope provides new information on the fusion process that He has also created CK Vulpeculae and shows that the deep, dense inner layers of a star, where heavy elements and radioactive isotopes are forged, can be shaken and thrown into space by stellar collisions.

"We observe the bowels of a broken star. "The astronomers also determined that the two stars that merged had relatively low mbades, one of them being a red giant star with a mbad of between 0.8 and 2.5. that of our Sun.

Being radioactive, aluminum 26 will disintegrate to be more stable and, in this process, one of the protons of the nucleus will disintegrate into a neutron. excited emits a photon of very high energy, which is observed as a gamma ray.

Previously, gamma ray emission detections showed that there are about two solar mbades of aluminum in the Milky Way -26, but the process that created the radioactive atoms was unknown.Because of the way in which gamma rays are detected, their precise origin was also, to a large extent, unknown. new measurements, astronomers have detected for the the first time, confirmed, an unstable radioisotope in a molecule outside our solar system.

At the same time, the team concluded that it is unlikely that the production of aluminum-26 by objects similar to CK Vulpeculae is the main source of aluminum-26 in the Milky Way. The mbad of aluminum-26 in CK Vulpeculae is about a quarter of Pluto's mbad and since these events are so rare, it is highly unlikely that they are the only producers of the isotope in the Milky Way. This leaves the door open to continue studying these radioactive molecules

Source: ESO