Kereksus is the closest neutron star to Kerbol.
"Neutron stars are the collapsed remnants of stars several times the mass of Kerbol. They have been theorized to exist for decades, but no real neutron star has ever been observed by Kerbalkind… until now. The discovery of Kereksus in the stellar neighborhood has mission planners scrambling to get a closer look. However, being basically a giant atomic nucleus, the neutron star is astronomically dense and has a surface gravity second only to a black hole. Manned missions are not recommended."
Kereksus is a neutron star. This means that its gravitational field is so potent that all the atoms inside it have all been crushed together to form neutron-degenerate matter. Kereksus is effectively a giant atomic nucleus made out of neutronium (otherwise known as element zero).
Kereksus is so dense that one teaspoon (5 milliliters) of its material would have a mass over 5.5×1012 kg (that is 1100 tonnes per 1 nanolitre), about 900 times the mass of the Great Pyramid of Kiza.
- Kereksus is actually a special type of rapidly rotating neutron star known as a pulsar. This means that two jets of deadly radiation emanate from Kereksus along its magnetic axis.