NASA's James Webb Space Telescope and Hubble Space Telescope are examining a pair of spooky-looking galaxies millions of light-years away.
Contained within a small galaxy located 5.3 million light-years away are big clues about how stars can form.
In fact, scientists didn't really expect that stars would even be able to still form at all in the dwarf galaxy known as Leo P, an image of which the James Webb Telescope recently captured in extraordinary detail in the constellation Leo.
First discovered in 2013, Leo P is relatively isolated from the influence of larger galaxies like the Milky Way and Andromeda. A team of researchers at the Space Telescope Science Institute recently found that Leo P formed stars early on but then stopped making them shortly after a period known as the Epoch of Reionization, which ushered in an end to the universe's "dark ages."
For most dwarf galaxies, when stellar formation comes to a halt, it never picks up again. But in an unexpected twist, the galaxy reignited after a few billion years and resumed birthing new stars.
An image captured in January and that NASA shared earlier in February not only shows Leo P, but its intriguing pattern of stellar formation that has baffled astronomers.
James Webb Space Telescope unveils star-forming Leo P galaxy
The team studied Leo P using NASA's James Webb Space Telescope, which imaged the dwarf galaxy with the instrument's Near-Infrared Camera (NIRCam.) By observing the galaxy in infrared light, Webb was able to help researchers determine the brightness and colors of thousands of ancient stars within, which in turn revealed information about Leo P's history.
The resulting image shows a portion of the Leo P dwarf galaxy, with a concentration of its bright stars at the lower right represented in blue.
At bottom center is a small blue bubble-like structure representing a region of ionized hydrogen surrounding a hot, massive O-type star. Together, the blue stars and bubble are part of a dwarf galaxy that extends beyond the image border.
Background galaxies are scattered across the image, with some particularly prominent spirals located at upper left and upper right.
Dwarf galaxies may hold secrets about stellar formation
Galaxies grow by accumulating gas and merging together. But many smaller galaxies, known as dwarf galaxies, have persisted throughout cosmic time without merging with others - intriguing astronomers interested in understanding how they evolved.
Leo P - named because its dearth of chemical elements besides hydrogen and helium make it "pristine" - has attracted interest because it pulled off a rare feat: Resuming stellar formation after new stars ceased forming for billions of years.
That stoppage happened during an epoch that occurred between about 150 million and one billion years after the Big Bang when the universe's first stars and galaxies formed.
The researchers collected data from about 15,000 stars in Leo P to determine that it went through three phases: an initial burst of star formation, a "pause" that lasted several billion years, and then a new round of star formation that is still continuing.
The astronomers hope that by studying galaxies early in their formation and in different environments, they can better understand the universe's origins and the forces that shape it. For that reason, the researchers plan to use Webb to observe whether a similar process is unfolding in another four isolated, star-forming dwarf galaxies.