1E .1, commonly shortened to 1E 161348-5055, is a
neutron star
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...
found in the centre of
RCW103 supernova remnant. It is a periodic
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
source with a period of 6.67 hours. It is approximately 2000 years old. It is 10,000 light years away in the
constellation Norma.
The star was discovered by the
Einstein Observatory
Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. Named HEAO B before launch, the observatory's name was changed to honor Albert E ...
.
This star is unusual because of its
rotation period
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...
of 6.7 hours. Its period is too long for a star of 2000 years, which should be rotating thousands of times faster. Instead, it is behaving more like a multi-million-year-old star. Another oddity occurred between October 1999 and January 2000. The star became 50 times brighter. The flare has faded since its peak but has not returned to its pre-1999 level. Two theories have been put forward to explain these phenomena.
The first is that the star possesses a massive
magnetic field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...
. This strong field would brake against the
debris disk left behind by the supernova, which has thus far been unknown to science. This theory would account for the slower than expected rotation but not for the increase in brightness.
An alternate explanation is that the star has a
low-mass X-ray binary
X-ray binaries are a class of binary stars that are luminous in X-rays.
The X-rays are produced by matter falling from one component, called the ''donor'' (usually a relatively normal star), to the other component, called the ''accretor'', which ...
. The companion star would orbit in an elongated orbit. When the companion is close to the neutron star, it would feed mass into it, creating the increased brightness. The drag created by the companion on the neutron star's magnetic field would also slow the rotation of the neutron star. If this scenario is the case, it is the youngest such system yet observed.
References
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External links
Supernova Leaves Behind Mysterious Object(SpaceDaily)
{{DEFAULTSORT:1E 161348-5055
Neutron stars
Norma (constellation)