Reclusive Neutron Star May Have Been Found in Famous Supernova

Supernova 1987A Images and Illustration.

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Since astronomers captured the bright explosion of a star on February 24, 1987, researchers have been searching for the squashed stellar core that should have been left behind. A group of astronomers using data from NASA space missions and ground-based telescopes may have finally found it.

As the first supernova visible with the naked eye in about 400 years, Supernova 1987A (or SN 1987A for short) sparked great excitement among scientists and soon became one of the most studied objects in the sky. The supernova is located in the Large Magellanic Cloud, a small companion galaxy to our own Milky Way, only about 170,000 light-years from Earth.

While astronomers watched debris explode outward from the site of the detonation, they also looked for what should have remained of the star’s core: a neutron star. 

Data from NASA’s Chandra X-ray Observatory and previously unpublished data from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), in combination with data from the ground-based Atacama Large Millimeter Array (ALMA) reported last year, now present an intriguing collection of evidence for the presence of the neutron star at the center of SN 1987A.

“For 34 years, astronomers have been sifting through the stellar debris of SN 1987A to find the neutron star we expect to be there,” said the leader of the study, Emanuele Greco, of the University of Palermo in Italy. “There have been lots of hints that have turned out to be dead ends, but we think our latest results could be different.”

When a star explodes, it collapses onto itself before the outer layers are blasted into space. The compression of the core turns it into an extraordinarily dense object, with the mass of the Sun squeezed into an object only about 10 miles across. These objects have been dubbed neutron stars, because they are made nearly exclusively of densely packed neutrons. They are laboratories of extreme physics that cannot be duplicated here on Earth. 

Rapidly rotating and highly magnetized neutron stars,called pulsars, produce a lighthouse-like beam of radiation that astronomers detect as pulses when its rotation sweeps the beam across the sky. There is a subset of pulsars that produce winds from their surfaces – sometimes at nearly the speed of light – that create intricate structures of charged particles and magnetic fields known as “pulsar wind nebulae.”

With Chandra and NuSTAR, the team found relatively low-energy X-rays from SN 1987A’s debris crashing into surrounding material. The team also found evidence of high-energy particles using NuSTAR’s ability to detect more energetic X-rays. 

There are two likely explanations for this energetic X-ray emission: either a pulsar wind nebula, or particles being accelerated to high energies by the blast wave of the explosion. The latter effect doesn’t require the presence of a pulsar and occurs over much larger distances from the center of the explosion. 

The latest X-ray study supports the case for the pulsar wind nebula – meaning the neutron star must be there – by arguing on a couple of fronts against the scenario of blast wave acceleration. First, the brightness of the higher energy X-rays remained about the same between 2012 and 2014, while the radio emission detected with the Australia Telescope Compact Array increased. This goes against expectations for the blast wave scenario. Next, authors estimate it would take almost 400 years to accelerate the electrons up to the highest energies seen in the NuSTAR data, which is over 10 times older than the age of the remnant.

“Astronomers have wondered if not enough time has passed for a pulsar to form, or even if SN 1987A created a black hole,” said co-author Marco Miceli, also from the University of Palermo. “This has been an ongoing mystery for a few decades and we are very excited to bring new information to the table with this result.”

The Chandra and NuSTAR data also support a 2020 result from ALMA that provided possible evidence for the structure of a pulsar wind nebula in the millimeter wavelength band. While this “blob” has other potential explanations, its identification as a pulsar wind nebula could be substantiated with the new X-ray data. This is more evidence supporting the idea that there is a neutron star left behind.

If this is indeed a pulsar at the center of SN 1987A, it would be the youngest one ever found.

“Being able to watch a pulsar essentially since its birth would be unprecedented,” said co-author Salvatore Orlando of the Palermo Astronomical Observatory, a National Institute for Astrophysics (INAF) research facility in Italy. “It might be a once-in-a-lifetime opportunity to study the development of a baby pulsar.”

The center of SN 1987A is surrounded by gas and dust. The authors used state-of-the-art simulations to understand how this material would absorb X-rays at different energies, enabling more accurate interpretation of the X-ray spectrum, that is, the amount of X-rays at different energies. This enables them to estimate what the spectrum of the central regions of SN 1987A is without the obscuring material.

As is often the case, more data are needed to strengthen the case for the pulsar wind nebula. An increase in radio waves accompanied by an increase in relatively high-energy X-rays in future observations would argue against this idea. On the other hand, if astronomers observe a decrease in the high-energy X-rays, then the presence of a pulsar wind nebula will be corroborated.

The stellar debris surrounding the pulsar plays an important role by heavily absorbing its lower energy X-ray emission, making it undetectable at the present time. The model predicts that this material will disperse over the next few years, which will reduce its absorbing power. Thus, the pulsar emission is expected to emerge in about 10 years, revealing the existence of the neutron star. 

A paper describing these results is being published this week in The Astrophysical Journal and a preprint is available online. The other authors of the paper are Barbara Olmi and Fabrizio Bocchino, also from INAF-Palermo; Shigehiro Nagataki and Masaomi Ono from the Astrophysical Big Bang Laboratory, RIKEN in Japan; Akira Dohi from Kyushu University in Japan, and Giovanni Peres from the University of Palermo. 

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory for the agency’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corporation in Dulles, Virginia (now part of Northrop Grumman). NuSTAR’s mission operations center is at UC Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror archive. JPL is a division of Caltech.

Image credit: Chandra (X-ray): NASA/CXC/Univ. di Palermo/E. Greco; Illustration: INAF-Osservatorio Astronomico di Palermo/Salvatore Orlando

Read more from NASA’s Chandra X-ray Observatory.

For more Chandra images, multimedia and related materials, visit:

http://www.nasa.gov/chandra

Last Updated: Feb 23, 2021

Editor: Lee Mohon

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mwhite
February 24, 2021 2:51 am

Supernova 1987A x-ray image, reminds me of something?????



Vuk
Reply to  mwhite
February 24, 2021 4:31 am

Imagination running wild is ok for artists but scientists are meant to be a bit more realistic
https://youtu.be/My_Y20TK0Pc

Nicholas McGinley
Reply to  Vuk
February 24, 2021 8:24 am

I have to wonder about calling this object the most famous object in astronomy.
My guess is, a small percentage of people could even come close to giving the correct answer if given the name or shown the picture and asked to identify it.
The Moon, the Sun, Venus, Mars, Halley’s comet…just about everyone knows what those things are.

Alan
Reply to  Nicholas McGinley
February 24, 2021 9:58 am

For deep sky observers, the moon is an infamous object.

Tom Abbott
Reply to  Nicholas McGinley
February 24, 2021 2:53 pm

It was a pretty big deal at the time.

Stephinie
Reply to  mwhite
February 24, 2021 7:44 am

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory for the agency’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corporation in Dulles,

Nicholas McGinley
Reply to  mwhite
February 24, 2021 8:26 am

You know someone who has theirs lit up with LEDs or something?

Rich Davis
February 24, 2021 3:45 am

“An increase in radio waves accompanied by an increase in relatively high-energy X-rays in future observations would argue against this idea. On the other hand, if astronomers observe a decrease in the high-energy X-rays, then the presence of a pulsar wind nebula will be corroborated.”

This sounds a lot like the discredited process of testing the null hypothesis. Don’t these fools know that you can’t argue against a dogma? You adjust the observations to fit the dogma. If necessary, you just make stuff up to prove the dogma. (It’s worse than we thought). Just ask any climastrologist!

menace
February 24, 2021 7:39 am

Given the shape of the nebula appears to be a rather tight torus (with the axis more or less coincidentally facing the earth) it must mean when stars explode most of the material is ejected along the stars plane of rotation and not going out in all directions.

I’ve always wondered why this happens. Most stars don’t really rotate that fast. I’d expect a fat torus and some energetic matter to be present even up near the polar regions. But maybe the rotation of the core spins up as the star collapses and this is what causes the most energetic material to be thrown out to be more or less within a plane?

When I see images of nebulae from older supernova remnancs they always seem to be 2-D and in a plane more or less perpendicular to the LOS from the earth. Are there any pictures of such nebulae that are oriented edge-on? I suppose they would not be as photogenic though, which is probably why they are never seen on imagery released to the public.

Nicholas McGinley
Reply to  menace
February 24, 2021 8:30 am

Magnetic fields are part of the answer.
But mostly it has to do with the concentration of material, not the absolute amount of it.
Consider the appearance of a planetary nebula.
It is a shell of material, but from certain angles and at certain wavelengths, many of them appear to be a smoke ring.

Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 8:33 am

Think of it this way…over 40% or the Earth’s surface is within the tropics.
Fully 2/5ths of it.
Nearly half.

Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 8:42 am

Also, keep in mind that what we see in such images is the parts that are glowing the most energetically, as they are excited by passing shock waves.
What is being illuminated is largely material that was ejected prior to the supernova as the shockwave and explosive debris collides with it.
Combined with the fact that the explosion was likely not symmetric, the effect of the stars magnetic field, and the piling up of material near the equator and at the poles, (plus the effects of rotation) and what we see is three rings.
This image is made to highlight the brightest part, the inner central ring. But other images look different, and the appearance itself has changed rather quickly over the years since we first saw the light from this ancient event.

R04468c7090638f47d13011f8ef5bd4ab.jpg
Last edited 5 months ago by Nicholas McGinley
Nicholas McGinley
Reply to  menace
February 24, 2021 9:12 am

The truth is, much is not understood about exactly what happens when the largest stars reach the end of their lives.
And they do not all appear the same way.
Think of the supernova remnant we call the crab nebula.
Of consider such objects as the Cat’s Eye Nebula, or Eta Carina and it’s Homunculus Nebula.
That last one has two lobes and very little around the central waist of the cloud.

Anyway, getting back to what objects look like edge on or whatever…much of that can be an optical illusion.
If a spherical shell of glowing gas is viewed from a distance, it will tend to look like a ring no matter what direction it is viewed from.
Because part seen as the center is rather thin, as compared to the outer periphery, where the line of sight includes a far larger amount of material.
Eta Carina, as seen in UV light by Hubble is attached.
Note to that many if not most images of dim and far away objects are false color images taken in particular wavelengths.
This image of 1987A though is visible light, as far as I can tell.

Most objects look much less interesting in visible light images, if they can be seen at all.
A look at a catalogue of images of this object show plainly that the ring is not all that is there.
The ring in fact consists of material that was ejected by the star tens of thousands of years before the supernova.

image_7344e-Eta-Carinae.jpg
Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 9:38 am

I have high hopes for this one.
It is far closer than 1987A, and may go supernova any second, literally.
Keeping in mind whatever it appears to do, actually happened 7500 years ago of course.
It could be brighter than the full moon for over a year.
A while back, it was the second brightest star in the sky for quite a long time.
Before that, it was a naked eye star.
It can be hard to find people talk about what they do not know, and so reading everything that is known or thought to be true about something like Eta Carinae is insightful: No one can claim to know what is going on with it, precisely how and why it looks like it does, what those two lobes are, why it did not explode all the way back when it brightened in 1837, or if and when it will ‘splode all the way.
That nebula is some 30 times the mass of the Sun!

maxresdefault.jpg
Reply to  Nicholas McGinley
February 24, 2021 3:17 pm

Every night when I go out to my little observatory here in NZ (www.stargazersbb.com) I glance up towards Eta Carina…just in case! I’d hate to miss it going bang. We also run two stacked RM-60 geiger counters with a coincidence detector to try and capture some gamma rays when it happens.

SN1987a was a wonderful sight to behold. One February night no star; and the next this bright spot. Over a few months it got slowly redder and fainter..a once in a lifetime experience.

Nicholas McGinley
Reply to  Alastair Brickell
February 24, 2021 3:46 pm

Yup…And right after Halley’s Comet.
I was in college at the time, and our farm was in Dark Sky country.
The big surprise though is how rarely a nearby supernova occurs.
I think we are overdue.

But I know for sure, huge numbers of people pay exactly zero attention to such things.
Think about when reporters stand on a street corner and ask people about things that should be common knowledge…like what century WWII was in.

Stephinie
February 24, 2021 7:43 am

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory for the agency’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corporation in Dulles,

Nicholas McGinley
February 24, 2021 8:20 am

“Only about 170,000 light years from Earth.”

Something about this made me laugh.

fretslider
February 24, 2021 8:36 am

SN1987A….

…there was massive devastation across the country and 18 people were killed. About 15 million trees were blown down. Many fell on to roads and railways, causing major transport delays. Others took down electricity and telephone lines, leaving thousands of homes without power for more than 24 hours.

Buildings were damaged by winds or falling trees. Numerous small boats were wrecked or blown away, with one ship at Dover being blown over and a Channel ferry was blown ashore near Folkestone. 

The Great Storm of 1987 – Met Office

Gosh!

Nicholas McGinley
Reply to  fretslider
February 24, 2021 10:01 am

All that from 25 neutrinos!
Imagine if one that is actually close explodes.

Stephinie
February 24, 2021 8:49 am

Since the technology has been developing, we could know more information about this supernova! I am a professional freelance writer and I write different topics such from financial topics to mathematics topics. I have recently written an article on mathematics, you could find help here for making your assignment ready on different topics in time.Your information inspires me writing new topics on supernova!

Nicholas McGinley
Reply to  Stephinie
February 24, 2021 10:03 am

Your comment reminds me to take everything I read with a grain of salt and to consider it with a skeptical point of view.

Reply to  Stephinie
February 24, 2021 3:08 pm

Yes, they’re interesting objects happening right in our ouwn stellar backyerd Yet most people have never heard of them. Good interesting writing about these objects with images could inspire the next generation of scientists…we don’t need more chefs, hairdressers or tattoo artists!

February 24, 2021 9:03 am

An interesting question is why neutron star pulsars have a magnetic field. They obviously do. But neutrons have no magnetic moment. There are various theories, all speculative, none well supported by basic known physics. Maybe as this one evolves we can answer the question.

Izaak Walton
Reply to  Rud Istvan
February 24, 2021 9:45 am

Rud,
The magnetic moment of the Neutron was first measured in 1934 and the current best estimate is
 μn = −9.6623647(23)×10−27 ​JT
https://en.wikipedia.org/wiki/Neutron_magnetic_moment

Nicholas McGinley
Reply to  Rud Istvan
February 24, 2021 10:24 am

My understanding is that neutron stars are thought to be only mostly neutrons, not 100% pure neutrons.
The oldest and most commonly postulated explanation is that the magnetic field they have is there because the star they formed from had a magnetic field, and this field is conserved and compressed into a far smaller volume during the collapse of the star’s core.
Note that some neutron stars have a huge magnetic field and are called magnetars.
Some of these are estimated to have a field strength with an energy density that translates into a mass equivalent over 10,000 times as dense as lead!

The way I look at it is, if no one had ever seen a thunderstorms, who would have ever guessed that they would have lightning? That they could produce gamma radiation?
Hell, even though we live right underneath them, it was only in our lifetime that the upward directed components of their discharge became accepted as being an actual thing. As recently as the 1980s, the leading “experts” on thunderstorms actively scoffed at reports of such things as jets and sprites shooting out of the top of thunderstorms.

So, considering how little we really know, and how completely human intuition fails us when we contemplate physical phenomena in the Universe, it does not really surprise me that such things are understood pretty much not at all.
Everything we know is so much guesswork, even things we can look at and examine and even things we can touch.
We cannot even agree on what is objectively factual regarding current events and human affairs.

Last edited 5 months ago by Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 3:04 pm

Yes, you’re quite right…we’re learning all the time. We think we’re just so smart but we’re not…simple cave men compared to what our descendants a few thousand years into the future will know.

I think thunderstorms can also produce antimatter…who would have thought!

Nicholas McGinley
Reply to  Alastair Brickell
February 24, 2021 11:31 pm

From a collection of little tiny droplets of water floating in air!
And of course some crystal of solid water mixed in.
Which turns out to be a large part of the whole story…but still.
Little tiny bits of water and snow and look what they can do!
So…what might be going on inside the collapsed core of the most massive and energetic stars after they explode and briefly outshine entire galaxies?
I am sure we have no idea.

Last edited 5 months ago by Nicholas McGinley
Vuk
Reply to  Rud Istvan
February 24, 2021 2:45 pm

Original star would have magnetic field caused by internal electric currents and it’s flux would be distributed through incredible large surface of these ginormous stars. When such star collapses to tiny fraction of its original size, principle of conservation of magnetic flux means that original value of flux which may not be particularly large would now increase by many orders of magnitude (R/r)^2 (ratio of areas of two spheres R-of initial star & r – of neutron star radii) hence strength of NS field may be billions or even a quadrillion times sun’s magnetic field. (largest stars R~nx10^9 km, Neutron star r ~ 15 km)

Vuk
Reply to  Vuk
February 24, 2021 2:52 pm

PS. Why gravity between two bodies (masses) act at speed of light, when gravity is nothing to do with electromagnetic waves or ‘light’ for that matter?
Getting late here, will post a comment tomorrow if you are still around.

Nicholas McGinley
Reply to  Vuk
February 24, 2021 4:00 pm

I think part of the explanation is, that any massless particles, like photons or gravitons, are constrained to move at the speed of light.
It should be called instead the speed of massless particles!

Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 4:01 pm

And neutrinos?
Nope. At least not all of them.
How does anyone know?
Because they change flavor.
No seriously!

Last edited 5 months ago by Nicholas McGinley
Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 4:16 pm

BTW, gravitons are not known for sure to exist.
But in the standard model, forces are transmitted via particles, called gauge bosons.
So their existence can be inferred. Also gravity waves are supposedly proven to exist, so…

Vuk
Reply to  Vuk
February 25, 2021 4:35 am

In our corner of our Galaxy space-time configuration the ‘Causal velocity’ happens to be C = ~300,000 km/sec. Thus, any mass-less ‘Cause’ to the ‘Consequence’ (photons aka EM radiation in vacuum, quantum mechanics waves in matter, etc) can propagate with a ‘causal’ velocity C no greater than ~300,000 km/sec.
It is that the Causal velocity propagation of the quantum mechanics wave which features in the E=MC^2, i.e. velocity at which matter can be converted into energy and vice-versa. Since the fission and fusion processes do not take place in the theoretical vacuum but quite opposite, in a dense plasma through which photons/EM waves can’t propagate, it may be concluded that they have nothing to do with the speed of light as ‘per se’, i.e. fission/fusion processes are governed by the Causal velocity C, while speed of light reaches the Causal velocity only in theoretical vacuum, else it is < C.
Back to gravity, if gravity and gravitational waves propagate with something like the ‘speed of light’ they may not have any EM properties, but are governed by the same more fundamental constant ‘Causal velocity C’. We also know that gravity of massive objects bends space and light, so if gravity/gravitons have EM property they would not propagate in straight lines. Since light can’t escape event horizon of a black hole, so it wouldn’t the gravitons but circle inside the event horizon, hence black hole wouldn’t be able to pull anything in. 
P.S. speed of light can not be measured unidirectionally for the obvious reasons.
Musings of an idle mind. 

Last edited 5 months ago by Vuk
rah
February 25, 2021 3:17 am

“…..but we think our latest results could be different.”…………”As is often the case, more data are needed to strengthen the case for the pulsar wind nebula.”……….”

But we just couldn’t wait to tell you what we might have found and it will only take a decade or so before may be able to confirm that we have found what we now think we may have found.

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