NASA's Webb telescope detects an extremely rare kilonova explosion

Alfonso Maruccia

Posts: 907   +280
Staff
Cosmic clash: When a compact neutron star merges with another neutron star or a black hole, it produces a rare and transient astronomical event known as a "kilonova" that generates bright gamma-ray bursts. NASA's James Webb Space Telescope recently observed its first kilonova.

Multiple ground-based telescopes and satellites were employed to detect and observe GRB 230307A, an "exceptionally bright" and rare gamma-ray burst, which NASA believes originated from a kilonova. Two neutron stars traveled from another galaxy before merging, producing heavy elements rarer than platinum on Earth.

A team of scientists studied GRB 230307A using the James Webb Space Telescope, Fermi Gamma-ray Space Telescope, Neil Gehrels Swift Observatory, and other telescopes. Their observations confirmed that the event was indeed a kilonova. Merging two neutron stars is believed to produce short gamma-ray bursts, which last less than two seconds. In contrast, long gamma-ray bursts lasting several minutes are associated with the explosion of massive stars.

The gamma-ray burst (GRB) from GRB 230307A is the second-brightest GRB observed in the past 50 years, as confirmed by NASA, being approximately 1,000 times brighter than a typical gamma-ray burst seen through the Fermi telescope. It was also unusually long, lasting for 200 seconds.

Eric Burns, co-author of the study and a member of the Fermi team at Louisiana State University, confirmed that despite its duration, the gamma-ray emission likely originated from a kilonova-level event.

By utilizing various space and ground-based observatories, scientists gathered sufficient information to piece together the GRB 230307A puzzle. They observed changes in the brightness of the gamma-ray burst and noted that the optical/infrared segment of the electromagnetic spectrum was faint, evolving rapidly and shifting toward the red end.

In terms of near-infrared observations, instruments aboard the James Webb Space Telescope played a pivotal role in discovering crucial details about the kilonova. The orbiting telescope helped scientists pinpoint the source of the binary neutron system, located in a spiral galaxy 120,000 light-years away from the eventual merger site.

Webb also detected emissions originating from tellurium (Te), a metalloid element with atomic number 52. Kilonovae have long been considered as ideal "pressure cookers" for the universe, where rarer elements heavier than iron can be synthesized. GRB 230307A appears to confirm this theory.

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For any amateur astronomers interested who can see objects of magnitude 18 or less, this researcher https://www.as.arizona.edu/people/faculty/ann-zabludoff runs a project that attempts to find a visual counterpart of events that generate gravitational waves. I'm not sure a kilonova would generate such a wave, but nonetheless, this is a chance to be a "citizen scientist."

Oof! Mag 18 is pretty faint. I've only ever seen Mag 14.2 in my 8" scope at a real dark sky site. 18 would be... a 24"?
 
Oof! Mag 18 is pretty faint. I've only ever seen Mag 14.2 in my 8" scope at a real dark sky site. 18 would be... a 24"?
I agree. It is quite low and you have to factor in the local light pollution. As to what size of scope, I do not know. However, here's a calculator that gives the general performance of any scope. https://skyandtelescope.org/observing/telescope-calculator/

IIRC - limiting magnitude is a function of mirror-radius^2
 
All elements are made in stars, super-novae, and on to other types of events like this and even more powerful explosions. Here's some info on the process - https://en.wikipedia.org/wiki/Supernova_nucleosynthesis
Right... but the article doesn't mention that or even something close. It's like the author wrote the headlines, then took a lunch break and came back and wrote a different article without changing the headlines. Thus, my logical leap comment.
 
I didn’t follow the logical leap to “where everything was made”.
It's a bit of an exaggeration. It would be fairer to say "where every heavy element has the potential to be made". Which is still an exaggeration if we don't upper bound the atomic number, but practically it is true.
 
I wonder how they'll explain the length of the bursts (2 orders magnitude greater than expected), given they have only seen very short length burst from so-called kilonova events.

Not sure it'll stand up to the test of time.
 
Oof! Mag 18 is pretty faint. I've only ever seen Mag 14.2 in my 8" scope at a real dark sky site. 18 would be... a 24"?
I'm interested in buying a scope and was looking at 6 or 8 inches. Do you have some recommendations for an amateur?

I was hoping to find something that is under 500 euro.
 
Right... but the article doesn't mention that or even something close. It's like the author wrote the headlines, then took a lunch break and came back and wrote a different article without changing the headlines. Thus, my logical leap comment.

yup .. welcome to Digitimes
 
I'm interested in buying a scope and was looking at 6 or 8 inches. Do you have some recommendations for an amateur?

I was hoping to find something that is under 500 euro.

I generally suggest to do 2 things before buying a telescope:

1) Use Binoculars for a few nights out at a reasonably dark sky site near you as they're so easy to use. Many people don't have access to even a reasonably dark sky site (much of Western Europe, East Coast US) but there are places that are better than others. I live in LA (bright!) but have a very good site "only" 1.5-2 hours away but in this bright light dome IMO that's a luxury.

Use SkyMaps to find good things for Binocs (and scopes) each month, I do!:


2) Look through other peoples' scopes! The best thing about finding that dark sky site is there will be other amateur astronomers out there too especially around new moon. Look online where the local astro club meets to view and drop by to have a look through a few 'scopes, covers both these recommendations! They love showing things to people through their scopes and you can get a first hand feel and look at all the designs and sizes.

tl;dr for the below. a 6-8" Dobsonian is a great first telecope but you should really look at the size of the 8" to make sure you will get it out and use it. A 6" Dob is almost a no-brainer, I could easily have started with one but they were scarce when I bought 20 years ago. Go-To (computerized finding) will be real nice and give less frustration at the beginning but costs more. Also buy a book that helps you start learning the night sky with a focus on viewing with a scope, Nightwatch by Dickinson is what I sarted with. This will help immensly.

A bit of background about the 3 types of telescopes and their advantages/disadvantages:

The best scope is the one you'll use the most, just like the best camera is the one you have with you the most (ie: on your phone). I have all 3 types and here are my observations:

Refractor: long tube, glass lens up front, the one most think of first. Pretty much never needs optical alignment, smallest light gathering, quickest to set up in 3-5" sizes. Needs the most expensive mount/tripod to stay stable as all the mass sits out at the ends of a long lever arm. And for me, the most used.

Reflector: Dobsonian mount is very stable with big mirror at the bottom, bulky, cheapest for larger sizes (6-12", and for super enthusiasts go up to 16 and 24" and above!!), needs alignment each time you use it but that becomes second nature real fast. I never bought a real Dob though I have custody of a friend's 10" and it's big. So I rarely use it but if I had bought an 6-8" Dob, it may have ended up being my only scope.

Cat (catadioptric, so descriptive): Jack of all trades, folded optics, compact, a little unwieldy getting it onto the mount/tripod. Middle on cost/aperture. The convenient design obstructs more of the light path so it's slightly behind the other designs' resolution at the same aperture but that design also allows larger scopes to be managed easier up to maybe 11-12" or so. I started with an 8" Cat (SCT design, there are others) with Go-To and used it exclusively for years and still do. IMO most convenient for Go-To computerized object finding.
 
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Right... but the article doesn't mention that or even something close. It's like the author wrote the headlines, then took a lunch break and came back and wrote a different article without changing the headlines. Thus, my logical leap comment.
Sorry about the article. Sometimes, one must take a leap to find out more. It's a complex process of which the basis is this https://en.wikipedia.org/wiki/Stellar_nucleosynthesis Then you have to take a leap to something else like "how are elements formed" "how are heavy elements formed", Element formation in super-novae, etc. Search engines are your friend.

Somewhat off-topic, I suppose what you experienced is part of the reason that AI sometimes gets it wrong - even if it is pretending to get it right - whatever "it" might be.
 
I generally suggest to do 2 things before buying a telescope:

1) Use Binoculars for a few nights out at a reasonably dark sky site near you as they're so easy to use. Many people don't have access to even a reasonably dark sky site (much of Western Europe, East Coast US) but there are places that are better than others. I live in LA (bright!) but have a very good site "only" 1.5-2 hours away but in this bright light dome IMO that's a luxury.

Use SkyMaps to find good things for Binocs (and scopes) each month, I do!:


2) Look through other peoples' scopes! The best thing about finding that dark sky site is there will be other amateur astronomers out there too especially around new moon. Look online where the local astro club meets to view and drop by to have a look through a few 'scopes, covers both these recommendations! They love showing things to people through their scopes and you can get a first hand feel and look at all the designs and sizes.

tl;dr for the below. a 6-8" Dobsonian is a great first telecope but you should really look at the size of the 8" to make sure you will get it out and use it. A 6" Dob is almost a no-brainer, I could easily have started with one but they were scarce when I bought 20 years ago. Go-To (computerized finding) will be real nice and give less frustration at the beginning but costs more. Also buy a book that helps you start learning the night sky with a focus on viewing with a scope, Nightwatch by Dickinson is what I sarted with. This will help immensly.

A bit of background about the 3 types of telescopes and their advantages/disadvantages:

The best scope is the one you'll use the most, just like the best camera is the one you have with you the most (ie: on your phone). I have all 3 types and here are my observations:

Refractor: long tube, glass lens up front, the one most think of first. Pretty much never needs optical alignment, smallest light gathering, quickest to set up in 3-5" sizes. Needs the most expensive mount/tripod to stay stable as all the mass sits out at the ends of a long lever arm. And for me, the most used.

Reflector: Dobsonian mount is very stable with big mirror at the bottom, bulky, cheapest for larger sizes (6-12", and for super enthusiasts go up to 16 and 24" and above!!), needs alignment each time you use it but that becomes second nature real fast. I never bought a real Dob though I have custody of a friend's 10" and it's big. So I rarely use it but if I had bought an 6-8" Dob, it may have ended up being my only scope.

Cat (catadioptric, so descriptive): Jack of all trades, folded optics, compact, a little unwieldy getting it onto the mount/tripod. Middle on cost/aperture. The convenient design obstructs more of the light path so it's slightly behind the other designs' resolution at the same aperture but that design also allows larger scopes to be managed easier up to maybe 11-12" or so. I started with an 8" Cat (SCT design, there are others) with Go-To and used it exclusively for years and still do. IMO most convenient for Go-To computerized object finding.
Great advice, but I will also add do not get any telescope that advertises a magnification of greater than 50x/inch of aperture. That is, if you see a scope that says it is 2-inches and its magnification is 200X avoid it like the plague.

Here's an article that is a good source, somewhat explains the concepts of choosing a scope, and has a link to an article about what they consider the best telescopes for beginners - https://www.skyatnightmagazine.com/advice/understanding-limits-telescope
 
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