Joheen Chakraborty

Astronomers have discovered a close pair of stars whose orbital dance is speeding up year after year. These are white dwarfs — superdense, cooled remnants of stars, roughly the size of Earth, where matter is compressed to a degenerate state.

Astronomers are monitoring X-ray flares from the vicinity of a black hole at the center of a galaxy. These flares repeat with a certain rhythm, like heartbeats. Normally, as a star approaches a black hole, the rhythm speeds up — just as a pulse quickens when running. But at the black hole 'Ansky,' the rhythm is slowing down.

At the centers of many galaxies lurk supermassive black holes. From time to time they 'scream' — unleashing powerful X-ray flares. Scientists have long puzzled over the nature of these 'quasi-periodic eruptions'.

A sugar cube sits on a saucer next to a cup of hot tea. Drop it in, and it dissolves within minutes. But if you lower it slowly, the sugar melts gradually, releasing its sweetness into the drink. Something similar is happening in two newly discovered stellar pairs, except the sugar is a brown dwarf and the tea is a star.

At the heart of galaxy 1ES 1927+654, a black hole behaves like a lighthouse with a faulty mechanism. Every six and a half minutes, it releases a burst of X-ray light, a rhythm astronomers have been tracking since 2022. At first, the beacon's tempo wandered — speeding up and slowing down, with intervals ranging from one beat every eighteen minutes to one every seven.

Two glowing embers left over from a fire whirl in the darkness, gradually drawing closer. With each turn, they lose tiny bits of energy that seep into the invisible ripple of space. That is exactly what the system eRASSU J060839.5−704014 looks like — a pair of white dwarfs (superdense stellar remnants) separated by a distance comparable to Earth's diameter.