March 22, 2023
The oldest-known star, officially called HD 140283 but nicknamed Methuselah, lies 190.1 light-years away. The Anglo-Australian Observatory (AAO) UK Schmidt telescope photographed the star in blue light for the Digitized Sky Survey.

What is the oldest star in the universe? What about the newest?

The oldest known star, officially named HD 140283 but nicknamed Methuselah, is 190.1 light-years away. The Schmidt Telescope at the Anglo-Australian Observatory (AAO) photographed the star in blue light for the Digitized Sky Survey. (Image credit: Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech and UKSTU/AAO)

Among the countless stars that shine in the vastness of space, some are so old that they have experienced the dawn of the universe, and others are so young that even the most powerful telescopes on Earth have not been able to observe them. But is it possible to know which star is the youngest and which is the oldest?

The youngest star in our universe is hard to pinpoint because stars are being born all the time, but there are a few candidates among those we know of. Instead, scientists have known about the oldest star on record — aptly nicknamed Methuselah — for decades.

Stars are born deep within vast clouds of dust and gas known as nebulae. According NASA (opens in new tab), some clumps of gas in the nebula are weighed down by so much material that their own gravity causes them to collapse (since more mass means more gravity), and the strong gravitational pull at the center of a collapsing cloud causes gas—mostly hydrogen—to accumulate in what becomes a star. These stellar embryos begin to fuse hydrogen nuclei into helium and emit radiation in the process. A star cannot be called a star until it radiates energy, which is how it becomes so incredibly bright. Some faint stars just shine into life.

New stars form all the time, but in 2022 astronomer Ruobing Dong and colleagues captured images of a young embryonic star in the constellation of the binary star Z Canis Majoris. Disturbances from a cosmic intruder were captured by the Subaru Telescope, the Karl G. Jansky Very Large Array, and the Atacama Large Millimeter/submillimeter Array. (Image credit: ALMA (ESO/NAOJ/NRAO), S. Dagnello (NRAO/AUI/NSF), NAOJ)

Astronomer Ruobing Dong (opens in new tab), assistant professor in the Department of Physics & Astronomy at the University of Victoria in Canada, observed these emerging stars. He led a 2022 study in the journal Nature Astronomy (opens in new tab) in a binary protostar system believed to be only about a million years old. Dong and his colleagues were able to put an approximate age on some of these star embryos. They often fire bursts, otherwise known as accretion bursts.

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