Earth-size diamond

This is not the real image of pulsar PSR J2222-0137 and its companion, the diamond white dwarf

As a star is running out of hydrogen to undergo fusion, its mass will determine the fate of the star. For a star that has mass more than eight times of our sun’s mass will undergo an explosion called supernova, and it will become a black hole or a neuron star. A star than is smaller than or about the size of our sun, called medium-sized star will become a white dwarf.

900 light years away from the Earth, in the direction of constellation Aquarius, there is a pulsar spinning 30 times per second. Pulsar is a spinning neuron star, and this pulsar is called PSR J2222-0137. As it spins, it sends out a radio signal and it is detectable by radio telescopes on earth as it pass the earth. Sometimes, the radio signal get delayed as it passes its companion object. Astronomers used Einstein theory of relativity to find out that the mass of the companion object is 1.05 times our sun’s mass.

Their efforts of trying to observe the companion object that is believed to be a white dwarf is futile even with optical and infrared light as it is too cold and faint. The white dwarf’s temperature is about 2700 degree celsius, 5000 times colder than the sun’s core. Astronomers believed that as it is composed mainly of carbon and oxygen, extremely dense and cold, the carbon has crystallized to diamond. The diamond is about the size of the earth with the mass of the sun.

You can read more about this white dwarf here.