---
title: "Something Peeled an Entire Layer Off This Star Like a Giant Orange"
description: "A team of scientists figured out what happened to Cassiopeia A, a star that had its outer layers blown away before it ultimately exploded in a supernova."
date: "2020-10-06"
modified: "2020-10-07"
authors:
  - name: "Dan Robitzski"
    link: "https://futurism.com/authors/danrobitzski"
url: "https://futurism.com/the-byte/something-peeled-star"
categories:
  - "Science & Energy"
tags:
  - "star"
  - "supernova"
  - "the digest"
---

# Something Peeled an Entire Layer Off This Star Like a Giant Orange

![A team of scientists figured out what happened to Cassiopeia A, a star that had its outer layers blown away before it ultimately exploded in a supernova.](<https://futurism.com/wp-content/uploads/2020/10/something-ripped-entire-outside-layer-star.jpg>)
*\<em\>Image: NASA\</em\>*

## Bare Bones

Before the star Cassiopeia A exploded in a supernova, something had already come by and stripped it bare.

The clouds of gas expelled by the supernova, *[Live Science](<https://www.livescience.com/cassiopeia-a-skinned-supernova.html>)*[ reports](<https://www.livescience.com/cassiopeia-a-skinned-supernova.html>), are missing hydrogen, which usually forms the outer layer of a star while heavier elements stay toward the core. Now, scientists think they know why: Cas A may have been too close to the earlier supernova of its neighbor, an explosion that would have been strong enough to blow the hydrogen layer away.

## Going Together

An international team of astronomers modeled how when one star in a binary system [blows up](<https://futurism.com/the-byte/dead-star-inside>), it can essentially "sandblast" the other one, as *Live Science* put it. [Their research](<https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/staa2898/5910511?redirectedFrom=fulltext>), published in the journal *Monthly Notices of the Royal Astronomical Society*, matches the existing data on what happened to Cas A and similar binary supernovae.

"This is enough for the second supernova of the binary system to become a stripped-envelope supernova," lead author Ryosuke Hirai, a researcher at The Australian Research Council Centre of Excellence for Gravitational Wave Discovery, [said in a press release](<https://www.ozgrav.org/news/revealing-the-lonely-origin-of-cassiopeia-a-one-of-the-most-famous-supernova-remnants>), "confirming that our proposed scenario is plausible."

## Controlled Demolition

The first supernova taking away Cas A's outer layer of hydrogen also likely sent it into a wildly unstable state, *Live Science* reports, potentially speeding up its own death.

The new research is only a model. But just as those models predicted, the researchers found a cloud of hydrogen 50 lightyears away: a shattered remnant from the first explosion.

*Editor's note 10/7/2020: An earlier version of this story misstated Cas A's distance from Earth. It has been updated.*

**READ MORE:** [Something huge ripped the skin off this star before it died](<https://www.livescience.com/cassiopeia-a-skinned-supernova.html>) \[*Live Science*\]

**More on cosmic destruction:** *[In Its Dying Gasp, Our Sun Will Obliterate the Asteroid Belt](<https://futurism.com/the-byte/sun-dying-obliterate-destruction-asteroid-belt>)*

## Author
Dan Robitzki is a senior reporter for Futurism, where he likes to cover AI, tech ethics, and medicine. He spends his extra time fencing and streaming games from Los Angeles, California.

### Author social links  
[Twitter](<https://x.com/danrobitzski>)