Astronomers have discovered the most distant star yet, a super-hot, super-bright giant that formed nearly 13 billion years ago at the dawn of the cosmos*.
But this luminous* blue star is long gone, so massive that it almost certainly exploded into bits just a few million years after emerging.
Its swift end makes it all the more incredible that an international team spotted it with observations by the Hubble Space Telescope. It takes eons* for light emitted from distant stars to reach us.
“We’re seeing the star as it was about 12.8 billion years ago, which puts it about 900 million years after the Big Bang,” said Johns Hopkins University doctoral student and astronomer* Brian Welch, lead author of the study published March 30 in the journal Nature.
“We definitely just got lucky.”
Welch nicknamed the star Earendel, an Old English name which means “morning star” or “rising light”.
“A fitting name for a star that we have observed in a time often referred to as ‘cosmic dawn’,” he said.
The previous record-holder, Icarus*, also a blue supergiant star spotted by Hubble, formed 9.4 billion years ago. That’s more than 4 billion years after the Big Bang.
In both cases, astronomers used a technique known as “gravitational lensing” – a term coined by Albert Einstein – to magnify the minuscule starlight. Gravitational lensing occurs when gravity from clusters of galaxies closer to us — in the foreground — serve as a lens to magnify smaller objects in the background. If not for that, Icarus and Earendel would not have been detectable given their vast distances, which would usually make individual stars impossible to pick out within their galaxy.
“Usually they’re all smooshed together,” said NASA astrophysicist Dr Jane Rigby. “But here, nature has given us this one star — highly, highly magnified, magnified by factors of thousands — so that we can study it. It’s such a gift, really, from the universe.”
Arizona’s National Science Foundation NOIRlab’s Dr Vinicus Placco, who was not involved in the study, described the findings as “amazing work.”
Placco said based on the Hubble data, Earendel may well have been among the first generation of stars born after the Big Bang. Future observations by the newly launched James Webb Space Telescope should provide more details, he said, and “provide us with another piece of this cosmic puzzle that is the evolution of our universe.”
Current data indicates Earendel was more than 50 times the size of our sun and an estimated one million times brighter, outsizing Icarus.
Earendel’s small, immature home galaxy looked nothing like the pretty spiral galaxies photographed elsewhere by Hubble, according to Mr Welch, but rather appeared to be “kind of an awkward-looking, clumpy object.”
Unlike Earendel itself, the galaxy has probably survived, he said, although in a different form after merging with other galaxies.
“It’s like a little snapshot in amber of the past,” NASA’s Dr Rigby said.
There’s a slight chance Earendel could be a black hole, although the observations gathered in 2016 and 2019 suggested otherwise to the researchers.
The star lasted barely a few million years before exploding as a supernova*. The most distant supernova seen by astronomers to date goes back 12 billion years.
The James Webb telescope — 100 times more powerful than Hubble — should help clarify how massive and hot the star really was, and reveal more about its parent galaxy.
“We are literally understanding where we came from because we’re made up of some of that stardust,” Dr Rigby said.
- cosmos: the universe as a whole
- luminous: producing or emitting light, bright, shining
- eons: an indefinite, very long period of time
- astronomer: scientist who studies the stars, planets and other natural objects in space
- Icarus: in Ancient Greek mythology, the son of Daedalus who flies too close to the sun
- supernova: the explosion of a large star, it’s the largest type of explosion in space
- What is the name of the special telescope that detected the star?
- Who originally coined the term “gravitational lensing”?
- Which new telescope is 100 times stronger than the Hubble?
- How many times larger than our sun is Earendel?
- How long after the Big Bang is Earendel thought to have formed?
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1. KWL chart
Complete a KWL chart (Know, Want to Know and Learnt) about the newly discovered Earendel star which existed billions of years ago.
There is lots of scientific information in this article, so sometimes it helps to complete a chart like this to summarise the information and form some questions you’d like to explore further.
KNOW (What I already know about this topic):
WANT TO KNOW (Questions you have after reading article):
LEARNT (What you now know after reading article):
Time: allow 20 minutes to complete this activity
Curriculum Links: English; Science; Critical and Creative Thinking
The Earendel star was estimated to be 50 times larger than the sun and one million times brighter. How do you think that would affect planet Earth if it was still in existence?
Time: allow 10 minutes to complete this activity
Curriculum Links: Science; Critical and Creative Thinking
To sum it up
After reading the article, use your comprehension skills to summarise in a maximum of three sentences what the article is about.
What is the main topic or idea?
What is an important or interesting fact?
Who was involved (people or places)?