Anirban Das and colleagues in their recent paper showed that, when dark asteroids travels through a star, it produces shock waves, which quickly propagate to the stellar surface, where it is released in the form of a transient optical, UV or X-ray emission. They also suggested how we can search and detect such signature. Their study recently appeared in Arxiv.
If you read our articles everyday, you may came across several studies which demonstrated that light dark matter (DM) particles can capture or produce inside stars or compact objects and can change their properties like mass, orbital period, luminosity etc. However, DM could also be in the form of objects of macroscopic mass and size. Such objects are hard to detect because of their rarity. According to several studies heavy DM asteroids can pass through earth but we haven’t detected one yet since the advent of human civilization. Now, Anirban Das and colleagues suggested that dark asteroids in the mass range of 10¯20–10¯11 can pass through stars. Thus, we must look them in the stars.
They point out that, because dark asteroids move supersonically in stars, dissipation through any non-gravitational interaction will generate shock waves. This allows the dissipated energy to quickly propagate to the stellar surface, where it is released in the form of a transient, thermal ultraviolet (UV) emission.
“Crucially, such events are correlated with the local DM density, but uncorrelated with the underlying activity of the star.”
We can detect such events without requiring a dedicated search with the help of next-generation survey telescopes. While, in a dense globular cluster, such events occur far more often than flare backgrounds, so, an existing UV telescopes could find them by monitoring regions of high DM density.
“At the opposite end of the mass range, impacts on the Sun are expected to occur annually for mass of dark matter, MDM ≲ 10¯19M, and would be energetic enough to be easily detected by solar observatories.”
“It would be interesting to see if the resolution of these instruments permits such impacts to be distinguished from solar flares. In many of these cases, it may be possible to find impact events in a reanalysis of archival data.”, concluded authors of the study.
Reference: Anirban Das, Sebastian A. R. Ellis, Philip C. Schuster, Kevin Zhou, “Stellar Shocks From Dark Matter”, Arxiv, pp. 1-13, 2021. https://arxiv.org/abs/2106.09033
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