This Neutron Star Mystery Has Left Astronomers Scratching Their Heads

Photo Credit: NASA's Goddard Space Flight Center/S. Wiessinger

Scientists have found a neutron star that might be holding mysteries to how these space objects evolve. The newly-discovered neutron star is way lighter than it was previously thought possible, undermining the understanding of space researchers about the evolution of stars.

According to a new paper, the neutron star has a mass equivalent to 77% of the Sun but has a radius of only 6.2 miles. This makes it much lighter than the neutron stars that have been observed until now, which usually have the same radius but their mass is 1.4 times the mass of the Sun.

Defying The Laws?

The team of researchers is led by Victor Doroshenko of the Eberhard Karls University of Tübingen in Germany. Their study, published in the journal Nature Astronomy, suggests the newly-discovered neutron star could be a new type of star altogether.

"Our mass estimate makes the central compact object in HESS J1731-347 the lightest neutron star known to date, and potentially a more exotic object — that is, a 'strange star' candidate," the paper reads.

Neutron stars are among the densest objects in the observable universe. They are usually born when supergiant stars come to the end of their life and go supernova. The star’s core can compress all the mass into an extremely dense object. As per scientific calculations, a teaspoon of a neutron star will have a mass of 2.2 trillion pounds. However, the newly found neutron star defies these boundaries.

Challenging Our Understanding Of The Universe

The team of researchers used the data gathered by the European Space Agency's Gaia spacecraft and discovered that the star is closer than was thought. The data enabled the team to recalculate the star’s mass.

The results, however, don’t align with the current definition of a neutron star, making this discovery a potential “strange star,” as per the team. This type of star is a hypothetical space object believed to be made up of mostly “strange quark” matter, making its temperature and mass low compared to other neutron stars.

The team has also hinted that such a strange star could be the reason behind fast radio bursts, powerful bursts of radio pulses that are yet to be understood completely. Simply put, this discovery could alter our understanding of the cosmos.

Are We Wrong About Universe’s Expansion Rate As Well?

Recently, a team comprising international researchers observed the light emitted from 1,550 supernova events. Some of these events happened near the Milky Way galaxy while some were observed millions of light-years away.

Interestingly, the findings of the study align with a few existing dark matter theories. Dark matter is an unknown substance that is yet to be measured or observed directly. However, the study fails to solve one of cosmology’s biggest puzzles -- the Hubble tension.