WASHINGTON: Scientists have spotted a burst of X-rays emanating from the core of a galaxy near our Milky Way, with a gradual increase in frequency that appears to be coming from a white dwarf – one on a destructive path. Very compact star grapes.
According to the researchers, observations made using the European Space Agency’s X-ray telescope orbiting XMM-Newton show a white dwarf that is near the point of no return – known as the event horizon – as it orbits the galaxy’s supermassive black hole.
“This is probably the closest thing we’ve ever seen orbiting a massive black hole,” said Megan Masterson, a doctoral student in physics at the Massachusetts Institute of Technology and lead author of the study. “The event is very close to the horizon.” which was presented this week at the American Astronomical Society meeting in Maryland and will be published in the journal Nature.
Black holes are extraordinarily dense objects with gravity so strong that even light cannot escape. While their immense gravitational pull pulls in anything — like stars, gas and dust — that strays too close, the researchers said the white dwarf doesn’t seem to be dying. Rather, it has stabilized its orbit around the black hole.
The galaxy is located about 270 million light years from Earth. A light year is the distance light travels in one year, 5.9 trillion miles (9.5 trillion kilometers).
Most galaxies have a supermassive black hole at their center. The new observations show the mass of the black hole, called 1ES 1927+654, is about a million times the mass of our Sun. The supermassive black hole at the center of the Milky Way, known as Sagittarius A*, is about four times as massive.
White dwarfs are among the most compact objects in the universe, although not as dense as black holes. Stars up to eight times the mass of our Sun appear destined to end up as a white dwarf. They eventually burn all the hydrogen they use as fuel. Gravity then causes them to collapse into the “red giant” phase and blow off their outer layers, eventually leaving behind a compact core roughly the diameter of Earth—a white dwarf.
It appears to have about 10% the mass of the Sun, traveling at about half the speed of light. It is passing through the extremely high-energy atmosphere surrounding the black hole and emits X-ray flashes as it circulates in this atmosphere. These flashes initially became shorter and shorter, dropping from every 18 minutes to seven minutes over a period of about two years, as the white dwarf got closer to the black hole and its orbit decreased in size, but then became stable.
Researchers estimate that the white dwarf is orbiting the black hole at about 5 percent of the distance that separates Earth from the Sun, or a little less than 5 million miles (8 million km).
He said its orbit is stabilizing, perhaps because the white dwarf’s outer layers are being sucked into the black hole, providing a kickback action that pushes the object past the event horizon and into oblivion. have to face He added that a white dwarf might actually be able to survive such a close encounter.
Scientists may be able to confirm that it is indeed a white dwarf using next-generation observatories such as NASA’s Laser Interferometer Space Antenna (LISA), which detects waves in spacetime. Designed for what are called gravitational waves.
“What’s interesting to me about this result is that it shows that objects can orbit very close to massive black holes, and so I’m looking at X-ray light and gravitational wave emissions with LISA. I am optimistic about the joint detection of these objects. It is scheduled to begin in 2035,” said Erin Kara, an MIT astronomer and co-author of the study.