Star Quakes and Monster Shock Waves
45 points
14 days ago
| 6 comments
| caltech.edu
| HN
chasil
11 days ago
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"When these two bodies finally merge, the black hole will typically swallow the neutron star whole."

Not whole.

A small amount of matter will escape, both iron nuclei (from the crust) and free neutrons.

The R-process of stellar nucleosynthesis will then take place.

As I understand it, a normal output between three and 13 earth masses of gold is typical.

This total mass is insignificant compared to the final mass of the combined object, but it is also the engine that creates many elements higher than iron on the periodic table.

https://en.m.wikipedia.org/wiki/Stellar_nucleosynthesis

https://iopscience.iop.org/article/10.3847/2041-8213/acba16

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DFHippie
11 days ago
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The article says R-process nucleosynthesis (it doesn't use this term) occurs when neutron stars combine but not when a black hole swallows a neutron star. Is this incorrect?

> "What this means is that a neutron star-black hole collision, while it might not erupt with material like a neutron star–neutron star collision, could power strong signals that telescopes can detect," Most says.

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chasil
11 days ago
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Examine the second link that I posted.

"For these conditions, the detailed properties of the outflow determine whether a full r-process can or cannot occur, implying that a wide range of observable phenomena is possible. We show that on average the disk outflow lanthanide fraction is suppressed relative to the solar isotopic pattern. In combination with the dynamical ejecta, these outflows imply a kilonova with both blue and red components."

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bdbenton5255
11 days ago
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Absolutely fascinating. Detecting ripples in the fabric of space and time? The NSF is still producing Nobel worthy discoveries.

I've been working on a Deep Convolutional Generative Adverserial Network (DCGAN) which utilizes astronomical data and have been on an astronomy kick.

Cutting funding to pure science research is a profound mistake, pure science research puts our nation at the forefront of technological discovery and is of national strategic importance.

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HelloUsername
11 days ago
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Based on the title I first thought it would be the "light echoes" from a supernova explosion:

https://www.youtube.com/watch?v=NwuVXtIU0is

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maomaomiumiu
11 days ago
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Hard to wrap my head around the scale of this. Starquakes, shockwaves, and gravitational ripples from colliding neutron stars—it’s like science fiction, but real. Wild what we’re able to detect and model nowadays.
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pixelpoet
11 days ago
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I would really love to go back to university and study numerical relativity, MHD etc. Such a fascinating and deep field, and I'm already struggling with just doing classical N-body accurately!
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xqcgrek2
11 days ago
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eh this seems to make a lot of unjustified assumptions approximations hyping some simulations that may or may not have any relevance to what happens in nature
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