Massive star's unusual death heralds the birth of compact neutron star binary

Massive star's unusual death heralds the birth of compact neutron star binary
The three panels represent moments before, when and after the faint supernova iPTF14gqr, visible in the middle panel, appeared in the outskirts of a spiral galaxy located 920 million light years away from us. The massive star that died in the supernova left behind a neutron star in a very tight binary system. These dense stellar remnants will ultimately spiral into each other and merge in a spectacular explosion, giving off gravitational and electromagnetic waves. Credit: NASA/JPL-Caltech/R. Hurt

Carnegie's Anthony Piro was part of a Caltech-led team of astronomers who observed the peculiar death of a massive star that exploded in a surprisingly faint and rapidly fading supernova, possibly creating a compact neutron star binary system. Piro's theoretical work provided crucial context for the discovery. Their findings are published by Science.

Observations made by the Caltech team—including lead author Kishalay De and project principal investigator Mansi Kasliwal (herself a former-Carnegie postdoc)—suggest that the dying star had an unseen companion, which gravitationally siphoned away most of the star's before it exploded as a . The explosion is believed to have resulted in a neutron star binary, suggesting that, for the first time, scientists have witnessed the birth of a binary system like the one first observed to collide by Piro and a team of Carnegie and UC Santa Cruz astronomers in August 2017.

A supernova occurs when a massive star—at least eight times the mass of the Sun—exhausts its nuclear fuel, causing the core to collapse and then rebound outward in a powerful explosion. After the star's outer layers have been blasted away, all that remains is a dense neutron star—an exotic star about the size of a city but containing more mass than the Sun.

Usually, a lot of material—many times the mass of the Sun—is observed to be blasted away in a supernova. However, the event that Kasliwal and her colleagues observed, dubbed iPTF 14gqr, ejected matter only one fifth of the Sun's mass.

"We saw this massive star's core collapse, but we saw remarkably little mass ejected," Kasliwal says. "We call this an ultra-stripped envelope supernova and it has long been predicted that they exist. This is the first time we have convincingly seen core collapse of a massive star that is so devoid of matter."

Piro's theoretical modeling guided the interpretation of these observations. This allowed the observers to infer the presence of dense material surrounding the explosion.

"Discoveries like this demonstrate why it has been so important to build a theoretical astrophysics group at Carnegie," Piro said. "By combining observations and theory together, we can learn so much more about these amazing events."

The fact that the star exploded at all implies that it must have previously had a lot of material, or its core would never have grown large enough to collapse. But where was the missing mass hiding? The researchers inferred that the mass must have been stolen by a compact companion star, such as a white dwarf, neutron star, or black hole.

The neutron star that was left behind from the supernova must have then been born into orbit with this compact companion. Because this new star and its companion are so close together, they will eventually merge in a collision. In fact, the merger of two was first observed in August 2017 by Piro and a team of Carnegie and UC Santa Cruz astronomers, and such events are thought to produce the heavy elements in our universe, such as gold, platinum, and uranium.

The event was first seen at Palomar Observatory as part of the intermediate Palomar Transient Factory (iPTF), a nightly survey of the sky to look for transient, or short-lived, cosmic events like supernovae. Because the iPTF survey keeps such a close eye on the sky, iPTF 14gqr was observed in the very first hours after it had exploded. As the earth rotated and the Palomar telescope moved out of range, astronomers around the world collaborated to monitor iPTF 14gqr, continuously observing its evolution with a number of telescopes that today form the Global Relay of Observatories Watching Transients Happen (GROWTH) network of observatories.


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More information: K. De el al., "A hot and fast ultrastripped supernova that likely formed a compact neutron star binary," Science (2018). science.sciencemag.org/cgi/doi … 1126/science.aas8693
Journal information: Science

Citation: Massive star's unusual death heralds the birth of compact neutron star binary (2018, October 11) retrieved 23 April 2019 from https://phys.org/news/2018-10-massive-star-unusual-death-heralds.html
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Oct 11, 2018
It looks rather like an odd shrimp.

Oct 13, 2018
That sure is a lot of conjecture

Oct 15, 2018
That sure is a lot of conjecture

Yes--that's how science works. In fact that's how human understanding of the world works--including your's.
We start with a conjecture about something, then look for evidence that we can rely on it to be true.

Oct 15, 2018
That may be a correct assumption but it does not mean the answer is correct alla the headline. Presumption does not make it true.

Oct 15, 2018
That may be a correct assumption but it does not mean the answer is correct alla the headline. Presumption does not make it true.


And neither is it claimed to be. Scientists are usually very careful about that sort of thing. Hence the title of the paper;

"A hot and fast ultrastripped supernova that ***likely*** formed a compact neutron star binary."

My emphasis.

Oct 15, 2018
That may be the title of the paper but it is not the headline of the above piece.

"Massive star's unusual death heralds the birth of compact neutron star binary"
My emphasis

Oct 15, 2018
That may be the title of the paper but it is not the headline of the above piece.

"Massive star's unusual death heralds the birth of compact neutron star binary"
My emphasis


And, as I never tire of pointing out, you should read the papers, not the fluff provided in press releases. Admittedly, some papers are paywalled, but 'science by press release' is not a good thing to do. It is typical of cranks - in particular, electric universe cranks. Not that I'm accusing you of being a crank. The authors of the paper do not write those headlines. That is usually done by the institution's PR team, who are most likely not even qualified in the relevant science.

Oct 15, 2018
That agaim may be true,but somewhere a line must be drawn.If this was talking about a person it would be be subject to slander or libel laws,but as it is cosmology anything goes.It is not how science works.

Oct 15, 2018
T.o wit.A star of a size,that nobody has estimated,has exploded,or not,and has not expelled an amopunt of matter,or not,and has ben siphoned off by a black hole,neutron star or white dwarf,or not and has turned into a neutron star.Or not.If that was any other branch of science it would be laughed out of the house

Oct 15, 2018
If that was any other branch of science it would be laughed out of the house


No, it wouldn't. The article is not a scientific paper. The paper is a scientific paper, and they are careful to use qualifying language. Such as 'likely', 'probably', etc. And there results are based on previous observation, and reasonable inferences.

Paper is here for those that can be bothered reading it:

http://science.sc...6411/201

Oct 15, 2018
Sorry JD.clicked the article,couldn't get past the paywall or whatever.

Oct 15, 2018
But likely,probably etc belong to the realm of statistics,not proper science,and we know what Mr Twain had to say about that

Oct 15, 2018
But likely,probably etc belong to the realm of statistics,not proper science,and we know what Mr Twain had to say about that


No, it is based on previous observation, and reasonable inferences. What would you have them do? Sit on it, until someone beats them to it? No, the best thing to do is put it in the scientific domain, where other scientists can assess it, model it, make their own observations, and either support or challenge it. Seems perfectly reasonable to me.

http://sci-hub.tw....aas8693 (shhhhhh!)

Oct 16, 2018
Cheers, will peruse, time permitting

Oct 16, 2018
@Martinchen
That agaim may be true,but somewhere a line must be drawn.If this was talking about a person it would be be subject to slander or libel laws,but ...
re: defamation law
yes and no

besides being dependent upon location, it must present a "false statement that, depending on the law of the country, harms the reputation of an individual, business, product, group, government, religion, or nation" - https://en.wikipe...famation

(a good general definition)

.

the above is an article for laymen, not scientists

laymen do not usually have the requisite educational background to comprehend the data (it's also why the study is linked)

it's a news article and the primary reason that source material is important (it validates or refutes the claims)

essentially, the above is click-bait leading you to greater knowledge with a reference for validation

the titles tend to be more colour than factual, which necessitates reading further

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