White Dwarf Plays Hide-and-Seek with Cosmic Dust ⚡ экспресс
Deep (over 30%) irregular eclipses with a period of 4.97 hours have been detected around the white dwarf ZTF J1944+4557 — near the Roche limit, where tidal forces tear bodies apart. This is only the second known system with debris transits after WD 1145+017. Spectra revealed circumstellar gas, and the lack of color dependence points to large dust grains (larger than 0.2 microns). The transits completely vanished for seven months and then resumed, as if someone restarted a cosmic pendulum. This system is a natural laboratory for studying the depletion and replenishment of disks from destroyed planets.
A dead star the size of Earth — a white dwarf, first spotted by William Herschel back in 1783 — has decided to play hide-and-seek. The ZTF telescope, heir to the ideas of Fritz Zwicky, caught it undergoing eclipses every 4 hours 58 minutes: the light drops by a third. The culprits: clouds of cosmic dust. Precise brightness measurements show the dust grains are larger than smoke particles, because they dim both blue and red light equally. Splitting light into colors reveals hot gas — the remains of a shredded asteroid.
The game is rigged: the pattern of eclipses changes faster than the clouds complete one orbit. In 2024, they disappeared entirely for seven months, only to return and block the star again in 2025. This isn't just hide-and-seek — it's the death throes of a planetary system, where a dusty ring is born and dies before our eyes.
🎯 The 4.97-hour orbital period is so short that one 'year' for these dust clouds lasts less than a polar day in Murmansk.