If the discovery announced Wednesday Confirmed, it will be The type of “star explosion” is not yet known : And astronomers announced three at once, respectively at 1680 light-years, 3720 light-years and 4900 light-years.

The basic principle It remains the same as with a supernova and a supernova: a thermonuclear explosion – the fusion of hydrogen atoms – which occurs on the surface of a star that has reached the end of its life. With a nova and a micronova, we are talking about a white dwarf: a dead star the size of the Earth, but whose mass is equal to the mass of the Sun. The Micronova privacy The explosion appears to have occurred only at the poles, and not at the entire surface: so we are talking about a relatively small explosion, about one millionth of the power of its big sisters, as European astronomers explained.

The fact that the ejection of material only occurred at the poles leads these astronomers to wonder whether one or more explosions It cannot occur on the same white dwarf. Une explication possible: la naine blanche ferait partie d’un système d’étoile double (illustration ci-dessus) et « volerait » à son compagnon de la matière —de l’hydrogène— qui, lorsqu’elle dépasse un certain seuil, proque Explosion.

The three events detected so far are based on data from the US satellite TESS (Transiting a satellite to survey the outer planets). Then, the European VLT telescope, in Chile, was able to confirm that they emanated from white dwarfs. Results Released on April 20 in the magazine temper nature.

However, if it is small on a cosmological scale, it remains “relatively” small. Such an explosion could burn about 20,000,000 billion pounds of matter. And those that occurred at 1,680 light-years away remained visible for 10 hours despite this distance.

Image: Artist’s drawing of a white dwarf, in the center of the blue disk, with a stream of energy stolen from the other star / Source: ESO / L. Calcada, M. Kornmeiser.