May 14, 2019

The violent deaths of the first stars

The remnants of a supernova explosion. Photo: NASA/CXC/SAO

The first stars born just millions of years after the Big Bang are thought to have been massive, bright balls of helium and hydrogen, with heavy elements like carbon, zinc and iron forming in their cores.

Driving the news: A new study published in the Astrophysical Journal details how these stars died, seeding the universe with elements that eventually gave rise to our sun, planets, other stars and more.

What they found: The new study suggests that when these stars turned into supernovas, they didn’t explode in a spherical ball. Instead, new research shows the explosions were actually asymmetrical, shooting powerful jets of heavy elements out into neighboring galaxies.

What they did: The scientists studied the star HE 1327-2326, which is thought to be a surviving second-generation star that formed after the first generation of stars exploded.

  • The star was very rich in zinc, which the researchers argue could only happen if a first generation star exploded and seeded HE 1327-2326’s part of space with the heavy element.
  • And a series of 10,000 simulations showed the only way to explain the zinc signal in the star — which is located about 5,000 light-years away — was if a first generation star asymmetrically exploded.
“The working hypothesis is, maybe second generation stars of this kind formed in these polluted virgin systems, and not in the same system as the supernova explosion itself, which is always what we had assumed, without thinking in any other way. So this is opening up a new channel for early star formation."
— Anna Frebel, co-author of the new study, said in a statement.

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Updated 27 mins ago - Politics & Policy

Top Senate Democrat says State Dept. is working on new Saudi arms deal

Secretary of State Mike Pompeo briefs reporters on May 20. Photo: Nicholas Kamm/pool/AFP via Getty Images

Senate Foreign Relations ranking member Bob Menendez (D-N.J.) wrote in a CNN op-ed on Wednesday that he learned that the State Department is currently working to sell thousands of additional precision-guided bombs to Saudi Arabia.

Why it matters: Democrats say that Steve Linick, the State Department inspector general who was ousted on Secretary of State Mike Pompeo's recommendation, was investigating the administration's previous effort to sell weapons to Saudi Arabia without congressional approval.

U.S. coronavirus death toll crosses 100,000

Data: Johns Hopkins University; Chart: Danielle Alberti/Axios

More than 100,000 Americans have died of the coronavirus, according to data from Johns Hopkins — a terrible milestone that puts the death toll far beyond some of the most tragic events in U.S. history.

By the numbers: The death toll from COVID-19 now stands at more than 34 times the number of people who died on 9/11.