Like the mythical Phoenix Bird rising from the ashes of its own funeral pyre to soar again through the skies, a pulsar rises from the wreckage of its massive progenitor star–which has just expired from the fiery explosion of a supernova. A pulsar is a newborn neutron star; a dense, rapidly rotating city-sized relic of an erstwhile massive star that has collapsed under the stupendous weight of its own crushing gravity–into the deadly point that its constituent protons and electrons have merged together to form neutrons. In September 2018, a team of astronomers announced that they are the first to have witnessed the arrival of a pulsar emerging from the funeral pyre of its dead parent-star. This came at the same time that the Selection Committee of the Breakthrough Prize in Fundamental Physics recognized the British astrophysicist Dr. Jocelyn Bell Burnell for her discovery of pulsars–a detection initially announced in February 1968.
This Special Breakthrough Prize was given to Dr. Bell Burnell”for fundamental contributions to the discovery of pulsars, and a lifetime of inspiring leadership in the scientific community.” Her discovery of pulsars half a century ago proved to be among the biggest surprises in the history of astronomy. This discovery raised neutron stars right out of the realm of science fiction to reach the status of virtual reality at a very dramatic way. Among a large number of later significant impacts, it led to several strong tests of Albert Einstein’s General Theory of Relativity (1915), and also led to a new comprehension of the origin of heavy elements in the Universe. Called metals by astronomers, heavy atomic elements are those that are heavier than helium.
The supernovae that provide birth to pulsars can take months or even years to fade away. Sometimes, the gaseous leftovers of the fierce stellar explosion itself crash into hydrogen-rich gas and–for a short time–recover their former brilliance. However, the question that has to be answered is this: could they remain luminous without this sort of interference, resulting in their bright encore performance?
In an effort to answer this nagging question, Dr. Dan Milisavljevic, an assistant professor of physics and astronomy at Purdue University in West Lafayette, Indiana, declared that he had witnessed this event six years after a supernova–dubbed SN 2012au–had blasted its progenitor star to smithereens.
“We haven’t seen an explosion of this kind, at this late timescale, remain visible unless it had some kind of interaction with hydrogen gas left behind by the star before explosion. But there’s no spectral spike of hydrogen from the data–something else has been energizing this thing,” Dr. Milisavljevic explained in a September 12, 2018 Purdue University Press Release.
If a newborn pulsar sports a magnetic field and rotates rapidly enough, it’s able to speed-up nearby charged particles and evolve to what astronomers term a pulsar wind nebula. This is likely what happened to SN 2012au, according to the new study published in The Astrophysical Journal Letters.
“We all know that supernova explosions create these kinds of rapidly rotating neutron stars, but we never saw direct evidence of it in this unique time frame. This is a vital moment when the pulsar wind nebula is bright enough to behave like a lighbulb illuminating the explosions outer ejecta,” Dr. Milisavlievic continued to explain in the Purdue University Press Release.
Lighthouses In The Sky
Pulsars shoot out a normal beam of electromagnetic radiation, and weigh-in at roughly twice our Sun’s mass, since they spin wildly about 7 times each second! The beams emanating from brilliant pulsars are so tremendously regular that they are often likened to lighthouse beams on Earth, and this beam of radiation is detectable as it sweeps our way. The radiation flowing out from a pulsar can only be seen when the light is targeted at the direction of the planet–and it is also responsible for the pulsed look of the emission. Neutron stars are extremely compact, and they have brief, regular rotational periods. This creates an extremely exact interval between the pulses that range approximately from milliseconds to seconds for any individual pulsar. Astronomers find most pulsars through their radio emissions.
Neutron stars can wander around space either as solitary”oddballs” or as members of a binary system in close contact with the other still”living” main-sequence (hydrogen-burning) star–or perhaps in the business of another stellar-corpse like itself. Neutron stars have also been observed nesting within brilliant, beautiful, and multicolored supernova remnants. Some neutron stars can even be orbited by a system of doomed planets that are utterly and completely inhospitable spheres which suffer a constant shower of deadly radiation screaming out from their murderous leading parent. Indeed, the first package of exoplanets, found in 1992, were the tragic planetary offspring of a mortal parent-pulsar. Pulsars switch off and on brightly, projecting their regular beams of light through the space between stars. Certain pulsars even rival atomic clocks in their precision at keeping time.
The newly-spotted pulses were separated from 1.35 second intervals that originated from the same location in space, and maintained to sidereal time. Sidereal time is set from the motion of Earth (or a planet) relative to the distant stars (rather than in respect to our Sun).
In their efforts to describe these exotic pulses, Dr. Bell Burnell and Dr. Hewish came to the realization that the extremely brief period of the pulses ruled out most known astrophysical sources of radiation, like stars. Indeed, because the pulses followed sidereal time, they couldn’t be explained by radio frequency interference originating from intelligent aliens living elsewhere in the Cosmos. When more observations were conducted, using a different telescope, they confirmed the presence of the truly odd and mysterious emission, and also ruled out any type of instrumental effects. It wasn’t till a second similarly pulsating source was discovered in a different region of the sky the playful”LGM” theory was completely ruled out.
All celebrities are immense spheres composed of fiery, roiling searing-hot gas. These monumental glaring stellar objects are mostly composed of hydrogen gas that’s been pulled into a sphere very tightly as the consequence of the relentless squeeze of the star’s own gravity. This is the reason why a star’s core becomes hot and dense. Stars are so extremely hot because their raging stellar fires are lit as a result of nuclear fusion, which causes the atoms of lighter elements (such as hydrogen and helium) to fuse together to form increasingly heavier and heavier atomic elements. The creation of heavier atomic elements from lighter ones, happening deep inside the searing-hot heart of a star, is termed stellar nucleosynthesis. The process of stellar nucleosynthesis begins with the fusion of hydrogen, which is both the lightest and most abundant atomic component in the Cosmos. The method ends with nickel and iron, which are fused only by the most massive stars. This is because smaller stars like our Sun are not hot enough to fabricate atomic elements heavier than carbon. The heaviest atomic elements–such as uranium and gold–are created in the supernovae explosions that end the”lives” of massive stars. Smaller stars go gentle into that good night and puff off their beautiful multicolored outer gaseous layers to the space between stars. Literally all of the atomic elements heavier than helium–the metals–were created in the hot hearts of the Universe’s myriad stars.
The procedure for atomic fusion churns out a monumental amount of energy. This is why stars shine. This energy is also responsible for developing a star’s radiation pressure. This pressure produces a necessary and delicate balance that fights against the relentless squeeze of a star’s gravity. Gravity tries to pull all of a celebrities substance in, while pressure tries to push everything out. This ceaseless battle keeps a star bouncy against its inevitable collapse that will come as it runs from its necessary supply of nuclear-fusing fuel. At that tragic point, gravity wins the battle and the star collapses. The progenitor star has reached the end of that long stellar road, and if it is sufficiently massive, it goes supernova. This powerful, relentless, merciless gravitational pulling speeds up the nuclear fusion responses in the doomed star. Where once a star existed, a star exists no longer.
Before they meet their inevitable death, massive stars succeed in fusing a core of iron in their searing-hot hearts. Iron cannot be used for fuel, and at this point the progenitor star-that-was makes its sparkling farewell performance to the Cosmos–sometimes leaving behind a wildly spinning pulsar.
Prior to the new study, astronomers already understood that SN 2012au was an odd beast inhabiting the celestial zoo. The weird relic was extraordinary and odd in a number of ways. Even though the supernova blast was not brilliant enough to be termed a “superluminous supernova”, it was bright enough to be quite energetic and continue for quite a long time. It finally dimmed in a similarly slow light curve.
Dr. Milisavljevic forecasts that if astronomers continue to observe the sites of exceptionally bright supernovae, they might see similar sea-changes.
“If there is a pulsar or magnetar end nebula at the center of the exploded star, it may push from the inside out and even accelerate the gas. If we return to some of those events a few years after and take careful measurements, we might observe the oxygen-rich gas racing away from the explosion even faster,” Dr. Milisavljevic commented in the September 12, 2018 Purdue University Press Release.
Superluminous supernovae are passing celestial objects of great interest in the astronomical community. This is because they are potential sources of gravitational waves and black holes, and lots of astronomers also theorize that they may be related to other forms of celestial blasts, such as gamma-ray bursts and rapid radio bursts. Astronomers are trying to understand the fundamental physics which is the foundation for them, but they are hard to observe. This is as they’re relatively rare and are located very far from Earth.
This new study aligns with one of Purdue University’s Giant Leaps, distance, which is a part of Purdue’s Sesquicentennial 150 Decades of Giant Leaps.
Dr. Milisavljevic continued to note that”This is a basic process in the Universe. We would not be here unless this was happening. Lots of the elements essential to life come from supernova explosions–calcium in our bones, oxygen we breathe, iron in our blood–I think it’s crucial for us, as citizens of the Universe to understand this procedure.” Wildlife Removal New York NY can assist with any wildlife issues you may have.