March 3, 2025
The James Webb Space Telescope captured images in the near-infrared wavelength range of the region near the Trapezium Cluster in the Orion Nebula.
SHANGHAI – Deep in space, mysterious wanderers roam freely , of planetary masses yet not hosted by stars. These celestial nomads, called planetary-mass objects (PMOs), have baffled astronomers since their discovery in 2000. How were these cosmic orphans born?
On Thursday, an international team led by China’s Shanghai Astronomical Observatory cracked the code in Science Advances: Violent collisions between newborn stars’ gaseous disks in crowded stellar nurseries are mass-producing these rogue worlds. The discovery not only solves a 25-year-old puzzle but also may rewrite cosmic classification rules.
Their unique formation channel gives them defining characteristics that set them apart from stars and planets.
Scientists say that two theories previously attempted to explain their origins. One is “Failed Stars” hypothesis, which says that PMOs might form directly from collapsing molecular clouds, but their small size prevents nuclear fusion.
The other is “Exiled Planets” hypothesis which claims that PMO could be gas giants ejected from host stars via gravitational slingshots.
Both theories were disproven by new evidence. NASA’s James Webb Space Telescope (JWST) observed hundreds of PMOs in Orion’s Trapezium Cluster, a vast population far exceeding predictions of the “Failed Star” hypothesis.
About 9% exist as binary/triplet systems, which is unlikely for exiled planets, and many host expansive gas disks up to 200 astronomical units wide, structures indicating a formation history with no stars in sight.
“PMOs are neither stunted stars nor runaway planets,” said lead researcher Deng Hongping of Shanghai Astronomical Observatory. “They’re products of cosmic chaos
China’s astronomers solve 25-year mystery of PMOs in deep space
China Daily
The James Webb Space Telescope captured images in the near-infrared wavelength range of the region near the Trapezium Cluster in the Orion Nebula.
SHANGHAI – Deep in space, mysterious wanderers roam freely , of planetary masses yet not hosted by stars. These celestial nomads, called planetary-mass objects (PMOs), have baffled astronomers since their discovery in 2000. How were these cosmic orphans born?
On Thursday, an international team led by China’s Shanghai Astronomical Observatory cracked the code in Science Advances: Violent collisions between newborn stars’ gaseous disks in crowded stellar nurseries are mass-producing these rogue worlds. The discovery not only solves a 25-year-old puzzle but also may rewrite cosmic classification rules.
Their unique formation channel gives them defining characteristics that set them apart from stars and planets.
Scientists say that two theories previously attempted to explain their origins. One is “Failed Stars” hypothesis, which says that PMOs might form directly from collapsing molecular clouds, but their small size prevents nuclear fusion.
The other is “Exiled Planets” hypothesis which claims that PMO could be gas giants ejected from host stars via gravitational slingshots.
Both theories were disproven by new evidence. NASA’s James Webb Space Telescope (JWST) observed hundreds of PMOs in Orion’s Trapezium Cluster, a vast population far exceeding predictions of the “Failed Star” hypothesis.
About 9% exist as binary/triplet systems, which is unlikely for exiled planets, and many host expansive gas disks up to 200 astronomical units wide, structures indicating a formation history with no stars in sight.
“PMOs are neither stunted stars nor runaway planets,” said lead researcher Deng Hongping of Shanghai Astronomical Observatory. “They’re products of cosmic chaos
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