The Lightest Black Hole Ever Detected?

Or the heaviest neutron star?

This is the question astronomers are asking, nearing a conclusion to a decades long mystery.

Some 800 million light years away (a light year equaling 6 trillion miles), the most extreme recorded mass ratio gravitational wave event has taken place, labeled as GW190814.

On August 12, 2019, a cataclysmic event was detected by gravitational wave machines in Italy and the United States. Ripples in space and time from an event 8,550 million trillion kilometers from our blue planet.

Both black holes and neutron stars are the remnants of dead stars.

“When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive die, they explode in a supernova and leave behind dense, dead remnants of stars called neutron stars.” per LIGO, the Laser Interferometer Gravitational Wave Observatory operated by MIT and Caltech and supported by the National Science Foundation.

This discovery toes the line between the two, a mass gap, occurring between the heaviest known mass neutron star (2.5x the mass of our sun) and the lightest known black hole (5x the mass of our sun or 5 solar masses). The object of the study clocked in at 2.6 solar masses.

In a publication in the Astrophysical Journal Letters, this object was found only “as it merged with a black hole of 23 solar masses, generating a splash of gravitational waves detected back on Earth.”

The paper concluded:

“The unique combination of masses and inferred merger rate for this event is difficult to produce in population synthesis models. The discovery of GW190814 may therefore reshape our understanding of the processes by which the lightest black holes or the most massive neutron stars form. Based on our rate density estimate, we may reasonably expect to detect more systems of this kind after a year at design sensitivity. This discovery may prove to be the first hint of a larger population that could change our perspective on the formation and mass spectrum of compact objects.”

Source

Comments

comments