A team of astronomers has detected the faintest known white dwarf , an ancient stellar remnant so cold that the carbon it contains has crystallized and given rise to a kind of immense diamond, the size of our planet .
Astrophysicist David Kaplan, a professor at the University of Wisconsin, Milwaukee, who participated in the study, is convinced that it is not a unique case. “These types of objects are out there , but they are so weak that it is very difficult to find them,” he says.
In fact, to discover this stellar gem, the researchers used data obtained by some of the largest radio telescopes in the world , including the Green Bank Observatory in West Virginia (USA).
White dwarfs of this type, a kind of stellar “corpses” that form when a star with a mass similar to that of the Sun collapses and forms an object the size of our planet, are composed mainly of carbon and oxygen.
These bodies slowly cool down over a very long process . The one that has just been announced is about 11,000 million years old, approximately the same as the Milky Way, and it accompanies the pulsar PSR J2222-0137 (a neutron star that emits intense radio emissions at intervals), located at about 900 light years from Earth.
“This white dwarf is 10 times fainter than any other that we have news of and 100 times more than any other found around a neutron star,” says Bart Dunlap, another member of the team, from the University of Carolina del North in Chapel Hill. As these experts describe in the Astrophysical Journal , the remnant would be at a temperature of 2,700 ºC, 5,000 times less than that found inside the Sun.
Foto: B. Saxton (NRAO/AUI/NSF)
