AAS Nova
Magnetar
A neutron star with a magnetic field a thousand trillion times Earth's.
A magnetar is a neutron star — a city-sized ball of matter left over from a supernova, so dense a teaspoon weighs a billion tonnes — with a magnetic field around a thousand times stronger than an ordinary one. The field is strong enough to distort atoms into needles and, closer than a thousand kilometres, would erase the magnetic strips on your bank cards. Occasionally the crust cracks under the strain and the star emits a burst of gamma rays. One such event in 2004 was bright enough to measurably ionise Earth's upper atmosphere from 50,000 light years away.
Where it has come up lately
Phys.org
ScienceDaily
Universe Today
ScienceDaily
Physics World
Related terms
Supernova (Type Ia and Type II)
Two unrelated ways for a star to explode, useful for two entirely different reasons.
The main sequence
The long, stable middle age a star spends fusing hydrogen in its core.
Hertzsprung–Russell diagram
The single plot that organises everything about stars.
Red giant
What a star becomes when the hydrogen in its core runs out.
Questions
What is Magnetar?
A neutron star with a magnetic field a thousand trillion times Earth's.
Why does it matter?
Occasionally the crust cracks under the strain and the star emits a burst of gamma rays. One such event in 2004 was bright enough to measurably ionise Earth's upper atmosphere from 50,000 light years away.