Kilonova

A kilo Nova (alternatively Macro Nova ) is an outburst of a binary star, whose electromagnetic radiation is powered by the radioactive decay of elements that were formed in the r-process. The concept of Kilo Nova refers to the released energy, which is approximately reached the thousand times the value of a classical nova and fainter than a normal supernova.

Kilo novae can form in a merger of two neutron stars or the merger of a black hole with a neutron star. Here, the less massive neutron star is destroyed by the tidal forces of the heavier companion. While most of the matter of the destroyed star is accreted from an accretion disk to the more massive companion, are 0.001 to 0.1 solar masses of the destroyed isotropic neutron star with a speed of 0.1 - discharged to 0.2 times the speed of light. The neutron-rich matter is converted within a few seconds by fission and beta decay in elements around, caused by the r-process. The newly synthesized radioactive elements decay, and this emitted radiation can be used as a 0.5- to 10 days continuous eruption with a luminosity 1041erg / s to 1042.5 erg / s are detected.

The spectrum of a kilo Nova should be unique as a quasi -thermal point with a temperature of 10,000 K and because of the high rate of expansion no spectral lines. The merger of two compact stars emit gravitational waves and also should be observable with future gravitational wave detectors such as LIGO. The ejected matter interacts with existing circumstellar matter, and by means of bremsstrahlung is likely a several days lasting Radio outbreak be detected.

The merger of two compact stars is also seen as the cause of gamma -ray bursts of short duration. Of the relatively close GRB 130603B, which can be interpreted as a kilo Nova, an afterglow in the infrared was observed.

Kilo novae are considered a major source for the heavy elements in the r- process viewed with atomic masses above 130, since the contribution of supernova ejecta to these elements seem to be too small to explain the measured values ​​in the interstellar medium.