Caught by a Stellar Kick: Webb Finds a Neutron Star ⚡ экспресс
Analysis of the second epoch of SN 1987A observations with JWST NIRSpec (at higher spectral resolution) and MIRI/MRS confirmed the presence of narrow lines [Ar VI] 4.53 µm, [Ar II] 6.99 µm, [S IV] 10.51 µm, [S III] 18.71 µm from the central region. Additionally detected are [Ca V] 4.16 µm, [Cl II] 14.37 µm, and possibly [Fe II] 1.64 µm. The lines are blueshifted by ~ –250 km/s, and the emitting region is spatially unresolved and offset southeast from the center, indicating a neutron star kick velocity of 510 ± 55 km/s. The [Ca IV] 3.21 µm line, in contrast, is offset to the north and redshifted by ~700 km/s, explained by scattering off dust with a characteristic grain size ~0.3 µm; dust absorption dominates at wavelengths >8 µm. Photoionization models of a pulsar wind nebula and a cooling neutron star are consistent with the observations, except for the [Fe II] line; differences between the models will emerge at shorter wavelengths as the dust optical depth in the expanding ejecta decreases.
Nearly 40 years ago, a supernova blazed in a nearby galaxy — the 1987A explosion. For a long time, the heart of the catastrophe was hidden behind cosmic dust. The James Webb Space Telescope pierced the veil and found a neutron star — a super-dense ball the size of a city.
Analysis of the spectrum (light broken into colors) showed the star is shifting. It's racing away at 500 km/s — as if it were booted out from the explosion's center. For comparison, that’s like crossing the entire United States from coast to coast in about 8 seconds. Such a 'kick' could come from the asymmetry of the explosion itself or the pressure of its own radiation.
At this pace, the star will leave the galaxy in hundreds of millions of years. It’s unclear whether it will become a pulsar — a spinning cosmic radio beacon — or simply cool down. Further observations by Webb, once the dust finally clears, will shed light. This discovery confirms the foresight of Fritz Zwicky (1930s) and adds to the story of pulsars, discovered by Jocelyn Bell Burnell.
🎯 If this neutron star were heading toward Earth, it would reach the Moon in just 13 minutes.