In 2020, astronomers added a new member to an exclusive family of exotic objects with the discovery of a magnetar. New observations from NASA’s Chandra X-ray Observatory help support the idea that it is also a pulsar, meaning it emits regular pulses of light.
Magnetars are a type of neutron star, an incredibly dense object mainly made up of tightly packed neutron, which forms from the collapsed core of a massive star during a supernova.
What sets magnetars apart from other neutron stars is that they also have the most powerful known magnetic fields in the universe. For context, the strength of our planet’s magnetic field has a value of about one Gauss, while a refrigerator magnet measures about 100 Gauss. Magnetars, on the other hand, have magnetic fields of about a million billion Gauss. If a magnetar was located a sixth of the way to the Moon (about 40,000 miles), it would wipe the data from all of the credit cards on Earth.
On March 12, 2020, astronomers detected a new magnetar with NASA’s Neil Gehrels Swift Telescope. This is only the 31st known magnetar, out of the approximately 3,000 known neutron stars.
After follow-up observations, researchers determined that this object, dubbed J1818.0-1607, was special for other reasons. First, it may be the youngest known magnetar, with an age estimated to be about 500 years old. This is based on how quickly the rotation rate is slowing and the assumption that it was born spinning much faster. Secondly, it also spins faster than any previously discovered magnetar, rotating once around every 1.4 seconds.
Chandra’s observations of J1818.0-1607 obtained less than a month after the discovery with Swift gave astronomers the first high-resolution view of this object in X-rays. The Chandra data revealed a point source where the magnetar was located, which is surrounded by diffuse X-ray emission, likely caused by X-rays reflecting off dust located in its vicinity. (Some of this diffuse X-ray emission may also be from winds blowing away from the neutron star.)
Harsha Blumer of West Virginia University and Samar Safi-Harb of the University of Manitoba in Canada recently published results from the Chandra observations of J1818.0-1607 in The Astrophysical Journal Letters.
This composite image contains a wide field of view in the infrared from two NASA missions, the Spitzer Space Telescope and the Wide-Field Infrared Survey Explorer (WISE), taken before the magnetar’s discovery. X-rays from Chandra show the magnetar in purple. The magnetar is located close to the plane of the Milky Way galaxy at a distance of about 21,000 light-years from Earth.
Other astronomers have also observed J1818.0-1607 with radio telescopes, such as the NSF’s Karl Jansky Very Large Array (VLA), and determined that it gives off radio waves. This implies that it also has properties similar to that of a typical “rotation-powered pulsar,” a type of neutron star that gives off beams of radiation that are detected as repeating pulses of emission as it rotates and slows down. Only five magnetars including this one have been recorded to also act like pulsars, constituting less than 0.2% of the known neutron star population.
The Chandra observations may also provide support for this general idea. Safi-Harb and Blumer studied how efficiently J1818.0-1607 is converting energy from its decreasing rate of spin into X-rays. They concluded this efficiency is lower than that typically found for magnetars, and likely within the range found for other rotation-powered pulsars.
The explosion that created a magnetar of this age would be expected to have left behind a detectable debris field. To search for this supernova remnant, Safi-Harb and Blumer looked at the X-rays from Chandra, infrared data from Spitzer, and the radio data from the VLA. Based on the Spitzer and VLA data they found possible evidence for a remnant, but at a relatively large distance away from the magnetar. In order to cover this distance the magnetar would need to have traveled at speeds far exceeding those of the fastest known neutron stars, even assuming it is much older than expected, which would allow more travel time.
A preprint of the Astrophysical Journal Letters paper by Blumer and Safi-Harb describing these results is available online.
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.
Image credit: X-ray: NASA/CXC/Univ. of West Virginia/H. Blumer; Infrared (Spitzer and Wise): NASA/JPL-CalTech/Spitzer
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Last Updated: Jan. 8, 2021Editor: Lee Mohon
Wondering where it is in regards to the magnetic sheet of the Milky Way in respect to us? Seems we’re about to pass thru the plane of the sheet one of these centuries…
Wiping out all the credit cards doesn’t strike me as all that bad of an idea.
Or more likely, there would have been no credit cards in the first place, so no data would have been lost from them.
I suspect that would be the least of our worries.
Intensity of gamma rays it emits would spell the end of all terrestrial life as we know it, not to mention the sun with its 5770 K is an iceberg in comparison, a magnetar’s surface temperatures normally runs into millions degree K.
Not to mention tidal forces that would crack the crust wide open.
From the article: “Secondly, it also spins faster than any previously discovered magnetar, rotating once around every 1.4 seconds.”
Wow! That’s hard to imagine. Something that big can spin that fast. The Universe is an amazing place.
I think magnetars spin slowly for neutron stars — has something to do with how they become magnetars. Typical neutron stars can spin far faster, like 716 rev/sec:
https://www.newscientist.com/article/dn8576-fast-spinning-neutron-star-smashes-speed-limit/
716 Hz spin is not typical, it is actually the fastest known (confirmed) pulsar spin rate – the spin-up pulsar PSR J1748−2446ad. Spin-up pulsars spin-up to due to accretion from a companion star.
Typical mature spin-down pulsars have spin periods around 1-3 sec (spin rate 0.3-1 Hz).
I wonder how fast a pulsar theoretically would have to spin to the point where centripetal force on the surface at the equator exceeds the force of gravity. Perhaps some relativistic effects somehow make such a spin rate impossible to achieve.
I am confused, as usual. If the rotation is getting slower doesn’t that mean that the volume is expanding? There is the conservation of angular montenum. Think of a figure skater who pulls her arms and the pushes her arms out away from her body. The rate of spin decreases as he pushes her arms out. If it estimated at only 500 years old, what was it like 500 years ago?… a near singularity? The more I learn about the universe, the more confused I become.
I think the gravity is so strong that the material remains rigid.
No, rather think of a skater spinning and NOT putting his/her arms back out. Their spin will just keep slowing gradually until it stops due to friction.
For neutron starts they gradually slow due to some similar effect. Since their main power is in their rotation (spin-down type neutron stars to not have any appreciable fusion occuring) the radio energy they emit is generated by their rotation-induced dynamics and thus the power lost due to the radiation has to slow down the rotation (i.e. the law of conservation of energy).
“If it estimated at only 500 years old, what was it like 500 years ago?”
I assume it was birthed as a supernova remnant like all neutron starts.
starts = stars
did some autocorrect kick in or did I somehow typo that twice???
grr
Astronomy is a fascinating subject. Like archaeology, the further we reach into the past, the more fantastical (phantasmagorical?) becomes the theories on origins. Some chaps on this site yesterday had an argument about facts changing not changing interpretations blah blah. Astronomy is a prime example of facts evolving to fit the latest observation. Like “determining the age” of a thing by its rotational speed “assuming a much higher speed earlier”. You don’t get more dumb-ass than that. I bet Gretha Thurnberg Liked this article on InstaTwatFaceGram.
Yesterday the stargazers let me know that Mars has a wobble. Not as much as earth, they say. Not as much as earth. So they admit earth has a wobble. Has anyone told Gretha and pals? Do they understand the implications for their bloody climate change? Why does no-one ever mention this stupid little fact?
Oh, wait, here we go:
https://greenpets.co.za/index.php/en/2-greenpets-natural-happiness/136-climate-change
There is an unexpected (binary bits value) relationship of the planetary orbital velocities (km/sec) when expressed as a function of distance from sun in ‘duodecim’ (12) light-seconds units. Earth is at 42=101010 DdLightsec ~ 500 sec (It appears that the God did invent the first binary digital machine, now known as the Solar system)
http://www.vukcevic.co.uk/SS-Binary.gif
There is a hypothesis that origin of its extremely strong magnetic field is something to do with Hall effect, but as far as I’m concerned our sun is enough of a puzzle for the time being.
Ok, say it formed 500 years ago, but what we see in any spectrum today is what was emitted 21,000 years ago. “Then we’re awake, but we’re very perplexed.” (The Waco Kid)
Actually it is 21500 years old as it took 21000 years for the light to arrive.For all we know 21000 years later it has shed all its angular momentum as energy bursts and is a collapsed neutron mass. (Though I suspect it will take a million years or so to appreciably lose energy)
Fair enough. So why don’t the scientists say it formed 21500 years ago?
Cuz it’s all Relative.
So this thing is one of just 31 of its kind discovered, and it’s just 500 years old (ok, corrected to 21,500 years old) in a universe 14 billion years old. Which is like, it was born practically the same day as we invented the means to detect it. How likely is that?
Very low if there are only 31 objects in the universe. Much better odds if there are trillions of objects in the observable universe.