A Magnetar of Unknown Origin, Capable of Destroying Atoms a Thousand Kilometers Away, Is Crossing the Milky Way

A rogue magnetar, named SGR 0501+4516, is crossing our galaxy without a clear trace of its birth, according to a study published in the journal Astronomy & Astrophysics. This object, initially discovered in 2008 by NASA’s Swift observatory, is one of the 30 known magnetars in the Milky Way, but its behavior challenges conventional theories about their formation.

Magnetars are neutron stars, stellar corpses composed almost entirely of neutrons. What makes them unique is their extreme magnetic field, up to a trillion times more powerful than Earth’s. If a magnetar passed halfway between Earth and the Moon, it would erase the information on every credit card on the planet, explains Ashley Chrimes, lead author of the study and researcher at the European Space Agency (ESA).

Worse still, if a person got closer than 1,000 kilometers, the magnetar would destroy their atoms one by one, turning into a sort of cosmic “death ray.”

The Mystery of Its Origin

At first, astronomers believed that SGR 0501+4516 had formed in a supernova, like most magnetars. In fact, it’s near a supernova remnant called HB9, only 80 arcminutes away in the sky (equivalent to the width of a pinky finger held at arm’s length). However, a decade of observations with the Hubble Telescope and data from ESA’s Gaia mission revealed something unexpected: the magnetar does not come from that stellar explosion.

magnetar milky way destroy atoms — NIR image (JHK bands) of the field of SGR 0501+4516 as imaged with Gemini/NIRI (see Table 1). SGR 0501+4516 is marked with crosshairs and is notably redder than the surrounding field stars. The image has dimensions 45 × 36 arcsec and is oriented north up, east left. Credit: A.A. Chrimes et al.

All the movement we measured is smaller than a pixel in a Hubble image, notes Joe Lyman, co-author of the study and astrophysicist at the University of Warwick (UK). Being able to make these measurements demonstrates Hubble’s exceptional long-term stability.

By tracing its trajectory, the team discovered that SGR 0501+4516 is moving too fast and in a direction incompatible with the nearby supernova remnant. When they retraced its path thousands of years into the past, they found no other remnant or massive star cluster that could explain its birth.

If the magnetar wasn’t born in a supernova, how did it form? Researchers are considering two possibilities: it could be the result of the collision of two less massive neutron stars, or we may be looking at a scenario in which a white dwarf (the dead core of a Sun-like star) absorbs material from a companion star until it collapses and becomes a magnetar.

Normally, this process triggers a nuclear explosion and the white dwarf disappears. But under certain conditions, it could collapse directly into a neutron star, explains Andrew Levan, co-author of the study and researcher at Radboud University (Netherlands) and the University of Warwick.

Key to Understanding Fast Radio Bursts

This magnetar could be the missing piece to explain one of the greatest enigmas in modern astronomy: fast radio bursts (FRBs), extremely intense but very brief (milliseconds) pulses of radio waves.

Some FRBs come from regions with stars too old to host recent supernovae. If SGR 0501+4516 formed without a stellar explosion, its existence would support the theory that “orphan” magnetars could generate these signals.

Magnetars like this could be behind extreme cosmic events, such as gamma-ray bursts, superluminous supernovae, and FRBs, says Nanda Rea, researcher at the Institute of Space Sciences (Barcelona, Spain).

The team plans to use Hubble to study other magnetars in the Milky Way and determine whether there are more cases like SGR 0501+4516. Each discovery brings astronomers closer to solving the puzzle of how these magnetic monsters are born and their role in the most violent phenomena in the universe.

Meanwhile, this wandering magnetar continues its journey through the galaxy, defying everything we thought we knew about the fate of dead stars.

SOURCES

NASA Hubble Mission Team, NASA’s Hubble Tracks a Roaming Magnetar of Unknown Origin

A.A. Chrimes, A.J. Levan, et al., The infrared counterpart and proper motion of magnetar SGR 0501+4516. Astronomy & Astrophysics, vol.696, no. A127. doi.org/10.1051/0004-6361/202453479