Stars originate and disappear according to strictly written rules. Their weight determines the length of their life and the method of extinction. Apparently, we all know about the stars so far, this newly discovered fast-rotating star (pulsar) should not exist.

Sun-like stars have been living for about 10 billion years. At the end of life, after all the hydrogen burns out, it increases its volume and becomes red giants. Later, the gaseous shell is dropped, becoming a nebula, leaving an extremely dense object called a white dwarf instead of a star.

Much more massive stars than the Sun live only tens to hundreds of millions of years. Their end is faster and more turbulent. The star explodes, leaving a neutron star in its place.

Huge Matter in a Small Orb

Scientists named the newly discovered neutron star PSR J0740 + 6620. In order to understand why this star is unusual, we need to look at the comparison of parameters:

The Sun is about 1.4 million kilometers in diameter, the neutron star PSR J0740 + 6620 is 30 kilometers in diameter, and its mass is 2.17 times bigger than of the Sun. This suggests that the newly discovered neutron star is a huge mass matter packed into a relatively small sphere.

Neutron star (left) and white dwarf

Another extreme is that the neutron star revolves around its axis 350 times in one second, while Earth can do it once every 24 hours. A fast-roating star is called a pulsar.

Measurement in Space

The pulsar PSR J0740 + 662 has a white dwarf near it. The two bodies orbit and obscure each other from the Earth’s perspective – astronomers used it to measure both bodies. Although it sounds a bit strange and it is hard to imagine for a man, very massive bodies can curl the entire space. As the white dwarf passes in front of the pulsar, the curvature of the space will delay its otherwise very accurate pulses. Astronomers measured it and were able to determine the weight of the white dwarf and then the weight of the pulsar.

According to scientists’ theory, the maximum possible weight of any pulsar is about 2.16 times that of the Sun. If the mass were larger and increased, for example, by collision with another pulsar, then the object collapses into a black hole. PSR J0740 + 6620 slightly exceeds this limit by one hundredth. Theoretically, it should not exist and is therefore an important discovery.

Source & credit:,B. Saxton/NRAO/AUI/NSF),,,