Hubble Discovered an Unusual Infrared Emission around a Neutron Star

Hubble Discovered an Unusual Infrared Emission around a Neutron Star

The detection of infrared emission around RX J0806.4-4123 opens up a new chapter in the exploration of interstellar space.

The collapsed core of a huge star, which has a total of between 10 and 29 solar masses before collapsing, is known as a Neutron Star. Generally, the mass of a neutron star ranges from 1.4 to 2.16 solar masses. According to scientists, they are the densest and smallest stars known to humanity if we ignore hypothetical objects like strange stars. A combination of Supernova Explosion and Gravitational Collapse of a massive star gives birth to these stars. Typically, they cool over time after their formation as they don’t generate heat, actively. Having said that, they may evolve even further due to a collision or an accretion.

Recently, the Hubble Space Telescope of NASA detected a strange Infrared emission from a nearby neutron star. Researchers have not managed to figure out the exact reason for that and a number of theories are circulating in the scientific community about the causes of this unusual light. One of them suggests that an energetic wind is originating from this neutron star which smashes into the gas of the interstellar space to produce these emissions. Another explanation claims that a dusty disk surrounding the neutron star is responsible for this amazing glow. Bettina Posselt, the Lead Author of the paper who works as an Associate Research Professor of Astronomy and Astrophysics at the Pennsylvania State University, referred to that in the following words:

One theory is that there could be what is known as a ‘fallback disk’ of material that coalesced around the neutron star after the supernova. Such a disk would be composed of matter from the progenitor massive star. Its subsequent interaction with the neutron star could have heated the pulsar and slowed its rotation. If confirmed as a supernova fallback disk, this result could change our general understanding of neutron star evolution.”

An international team of researchers comprising of experts from the Sabanci University, University of Arizona, and Pennsylvania State University came up with this outstanding discovery. Contrary to previous beliefs, they found that the neutron stars can be studied in infrared light for exciting information. Prior to this study, neutron stars were observed only in high-energy emissions like radio and X-rays. The scientists associated with this research are confident that this observation will help astronomers to understand the evolution of neutron stars. Posselt mentioned that by saying,

This particular neutron star belongs to a group of seven nearby X-ray pulsars — nicknamed ‘the Magnificent Seven’ — that are hotter than they ought to be considering their ages and available energy reservoir provided by the loss of rotation energy. We observed an extended area of infrared emissions around this neutron star — named RX J0806.4-4123 — the total size of which translates into about 200 astronomical units (approximately 18 billion miles) at the assumed distance of the pulsar.”

Due to their very fast rotation, neutron stars are also called ‘Pulsars’. The fact that this rotation causes time-variable emission from light-emitting regions is the reason behind this name. The researching team published their findings in the Astrophysical Journal and explained the two possible explanations which might have led to this unusual emission. The first one of them is linked with a disk of dust (already discussed above) while the second one refers to a ‘Pulsar Wind Nebula’. Posselt explained it to the world and said,

A pulsar wind nebula would require that the neutron star exhibits a pulsar wind. A pulsar wind can be produced when particles are accelerated in the electrical field that is produced by the fast rotation of a neutron star with a strong magnetic field. As the neutron star travels through the interstellar medium at greater than the speed of sound, a shock can form where the interstellar medium and the pulsar wind interact. The shocked particles would then emit synchrotron radiation, causing the extended infrared signal that we see. Typically, pulsar wind nebulae are seen in X-rays and an infrared-only pulsar wind nebula would be very unusual and exciting.”

Scientists, from all parts of the world, have appreciated this effort and are determined to explore more about the evolution of neutron star by studying them in infrared light. They believe that it will improve their understanding of this awesome celestial object in the coming years.

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