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Our universe is full of stars. These oddballs always mystify us. Let us know about some strange stars of our Milky Way galaxy.

You understand what stars are doing. They are out there, doing their thing, fusing into helium a whole lot of hydrogen, shining the joint.

But some stars differ slightly from the standard. Not content with just lighting the night sky like a gigantic disco, they are zooming, shimmering, dim and even hanging around seemingly older than the real Universe. These are the oddballs of our galaxy, and we love everybody.

RX J0806.4-4123

Strange stars of our Galaxy. (Nahks Tr’Ehnl, Penn State)

Dead star, Pulsar RX J0806.4-4123, was noted to emit lengthy distances of infrared radiation. It is another strange star of our galaxy. This is not so uncommon by itself, but the expanded emission of RX J0806.4-4123 is only infrared. That was never seen before. Generally, through X-ray and radio emissions we see pulsars.

“We noted an expanded region of infrared emissions around this neutron star. Its complete volume translates into about 200 astronomical units (or 2,5 times Pluto’s orbit around the Sun) at the pulsar’s presumed range.”

There are two possible reasons. A material fall-back disc that coalesced after the supernova around the star. Basically, the proper material of the dead star, interfering with its typical emissions. This could have consequences for our knowledge of the evolution of neutron stars.

Or it might be a pulsar wind nebula, formed when a strong wind from a pulsar blows back the material left behind from the explosion of the star. Hollowing out a cavity in the nebula. But in the X-ray spectrum, these are generally seen. A pulsar wind nebula infrared-only would actually be a fresh and interesting discovery.

PSR J0002+6216

Strange stars of our Galaxy. (J. English/University of Manitoba/NRAO/F. Schinzel et al./DRAO/Canadian Galactic Plane Survey/NASA/IRAS)

PSR J0002 + 6216 is a strange star of our galaxy. We are not sure where the star is headed, but we know it’s going quickly there. It travels at 1,130 kilometers per second (700 miles per second) at the absolute breakneck velocity. That could take in six minutes from Earth to the Moon. It is one of the fastest stars we ever saw.

In the Milky Way, there are some of these runaway “hypervelocity” stars, but few with roots as clear as J0002. It’s a pulsar, a sort of fast-rotating neutron star-a huge star’s collapsed core after it’s gone supernova.

It was expelled from the latest supernova explosion’s growing cloud. Leaving behind a path after punching through the exterior debris shell of the explosion. The supernova was so strong that the star was knocked out and sent through the galaxy careening.

Apep

(ESO/Callingham et al.)

Hidden in a sinuous cloud of glowing dust, last year astronomers discovered something incredible. A binary star named Apep on the brink of a dramatic supernova. And when it goes on, there’s a nice possibility that it will spew a gamma-ray burst, releasing more energy in 10 seconds than the Sun might have in 10 billion years.

We have never seen a gamma-ray burst in the Milky Way before. The two stars are also uncommon-stars from Wolf-Rayet. These are very warm, very luminous, very ancient stars that usually have at least twenty-five times the Sun’s mass that they lose at a tremendous pace. Since this stage in the life of a star is so short, we don’t see many of them at all.

As the two stars orbit each other, they churn into a spiral shape the mass they shed. Much like a lawn sprinkler, producing a rare nebula form called a pinwheel.

HD 140283

Strange stars of our Galaxy. (Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, and UKSTU/AAO)

HD 140283 is another strange star of our galaxy and is actually a very peculiar star. It’s ancient-super old. As in, the ancient start of the Universe. It’s not terribly unusual. Here and there, the Milky Way is sprinkled with ancient stars. But none of the others appear to be older than the Universe itself.

HD 140283 aka the Methuselah star. The Universe is approximately 13.8 billion years old. HD 140283 appeared to be about 14.5 billion years old based on Hubble measurements of its brightness in 2013.

Look, there was an error margin of 800 million years. Which implies it could readily still be younger than the Universe, even according to those calculations. And it should be, in fact, unless our perception of the Universe is incorrect.

Tabby’s Star

Strange stars of our Galaxy. (NASA/JPL-Caltech)

The hype is now dead. But we don’t believe we are ever going to stop being deeply curious about the secrets of KIC 8462852 aka Tabby’s Star. Discovered by Yale University’s astronomer Tabetha Boyajian, it showed some truly uncommon brightening and dimming behavior.

The changes are not of the kind you would expect from orbiting planets, nor are they a variable star. It is apparently random, with bright and dim periods lasting for arbitrary quantities of time and darkening up to 22 percent.

Some wavelengths are blocked more than others. Which excludes an “alien megastructure” such as a Dyson sphere. It is also too ancient to have enough of a protoplanetary disc left to trigger that amount of light blockage.

Other theories include a ringed planet passing before the star. Either totally huge or lower with an orbital wobble. A swarm of comets, space junk, a star swallowing a planet or something occurring within the star itself.

The most probable culprit is some kind of dust and a heck ton of it. But we will never really understand it as well.

EPIC 204376071

Strange stars of our Galaxy. (GrandpaFluffyClouds/reddit)

Wait until you hear about EPIC 204376071 if you thought KIC 8462852 was intriguing. Astronomers revealed earlier this year that something blocked this star’s light. A mere 440 light-years away, for a whole day by up to 80 percent.

It dimmed quite abruptly, hit that 80 percent peak, and then lit up again more slowly, likely because there was something going on before it.

A tilted ring system orbiting the star would be the nearest match for the light curve. However, it would have to be very big, and the model did not fit precisely. It needed a tighter orbit than was feasible based on the observation span of 160 days.

Astronomers take more star readings to attempt and find out if something orbits it. So, for now, we just have to sit tight. And the suspense is killing us!

HD 101065

Now, this star is just an utter strange legend. It’s called HD 101065, or the Przybylski’s Star. Nothing really is normal about it. It belongs to a speedily oscillating class called Ap stars. That implies it’s a chemically strange Ap star class subtype (the p stands for’ peculiar’) whose light pulsates very fast.

Yet the star itself has a very slow rotation. Every 188 years, HD 101065 rotates only once. That might be due to unusual chemistry, as it tends to have Ap stars. There is chemistry like no other Ap star except HD 101065.

It has small iron and nickel quantities, but elevated quantities of heavy elements like strontium, caesium, uranium, and neodymium. Moreover, it appears to have an elevated amount of components called actinides. The only star they were discovered in.

These are the heavy elements with atomic numbers from 89 to 103. All of which are radioactive from actinium to lawrencium. They appear as short-lived radioactive isotopes in HD 101065. It is quite disconcerting as their short half-life implies they should be gone for a long time.

The best explanation is that these actinides are hypothesized to exist somewhere out there in the Universe as the decayed form of as-yet unknown and long-sought super-heavy elements.

XTE J1810-197

Magnetars are some of the strangest dead stars out there, and XTE J1810-197 is the oddest of all. They are neutron stars with extremely intense magnetic fields. About a quadrillion time, stronger than those of Earth.

XTE J1810-197 is one of just four of the 23 known radio waves emitting magnetars, and it did so fairly reliably until around 2008. Then it fell totally silent on the radio-until its radioactivity began again in December last year.

But there was something else. The activity was less dramatic and the pulse profile more subdued. With millisecond-scale oscillations that as the magnetic field shifts could potentially be related to surface waves in the stellar crust.

We still don’t comprehend these strange star beasts but keeping track of XTE J1810-197 could pone up some hints.

Swift J0243.6+6124

Okay, so neutron stars are pretty strange. Another is Swift J0243.6 + 6124, and gosh it is always a puzzle.

It has accreted matter from a nearby binary companion and sprawled something called relativistic jets. These are not uncommon for neutron stars, as are active black holes-plasma high-speed jets, shooting out of the neutron star or black hole perpendicular to the accretion disc.

The accurate mechanism behind jet manufacturing is not known to scientists. They believe that material from the innermost edge of the accretion disc is funneled along magnetic field lines. That function as a synchrotron to accelerate the particles before starting them at tremendous speeds.

The issue with Swift J0243.6 + 6124 is that for a neutron star it has an extraordinarily strong magnetic field. Previously, jets were only found in neutron stars with weak magnetic fields. Leading to a hypothesis that they might be restricted by magnetic fields. It is compensated for by Swift J0243.6 + 6124. But it also offers a fresh source to test how magnetic fields impact jet launch, so it’s fairly nice.

Mira

(NASA/JPL-Caltech/C. Martin, Caltech/M. Seibert, OCIW)

Mira is another strange star of our galaxy. It is going to die. One portion of it, Mira A, once bright like the Sun, is now a red giant. With a periodic 11-month cycle shucking off its exterior layers over time. It is only noticeable in that process to the naked eye as part of the Cetus constellation for a month.

It has a binary companion, Mira B, a dead star called a white dwarf. The developmental endpoint of stars not sufficiently huge to fall into a neutron star. This white dwarf is accreting the matter shucked off by Mira A. Fascinatingly, this seems to start forming a protoplanetary disc, which was earlier only feasible with very young stars.

Baby planets forming a dead star-how poetic they are. As the whole structure passes through the night sky, it leaves in its wake a path of shed stuff. This ‘tail’ feels like a comet a little bit. If a comet could trail behind it 13 light-years of material. In a sky complete of stunning stuff, it’s one of the most amazing things.

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