Near-perfect cosmic sphere discovered hidden beneath the galactic plane, mysterious in size and distance

Telios - whose name comes from the Greek for "perfect" - was discovered in radio images taken by the Australian Square Kilometre Array Pathfinder (ASKAP) telescope in Western Australia as part of the "Evolutionary Map of the Universe" project. It is a supernova remnant (SNR), an expanding cloud of gas and radiation after the explosion of a star.

Typically, SNRs are faintly spherical as supernova explosions spread out in all directions, but over time many become distorted by the effects of other explosions or stellar winds. Finding a remnant with a nearly perfectly symmetrical shape like Telios is extremely rare. In a study uploaded to the arXiv server on May 7 and accepted for publication in the journal Publications of the Astronomical Society of Australia, the researchers describe Telios as one of the most rounded SNRs ever recorded in the Milky Way.

The newly discovered supernova, nicknamed Telios, is almost perfectly circular. Image: Filipović et al. 2025, arXiv.

What makes Telios even more unusual is its extremely low brightness, which suggests that it is either very young or extremely old. However, based on its nearly perfectly circular shape, the researchers are more inclined to believe that Telios is a young SNR, as most of the remnants will have been distorted over time.

Due to its low brightness, determining Telios' distance from Earth is difficult, leaving its actual size unknown. Estimates suggest it could be between 7,170 and 25,100 light years away and between 45.6 and 156.5 light years in diameter - dozens of times larger than our solar system.

Telios lies below the galactic plane, the region where most of the matter, stars, and planets—including our solar system—are concentrated around the supermassive black hole at the center of the Milky Way. This unusual location complicates determining the object’s exact distance and size. However, Telios is still part of our galaxy.

Perfectly spherical SNRs are extremely rare. In the past, only a few similar objects have been discovered in dwarf galaxies orbiting the Milky Way, such as SN1987A and MC SNR J0509–673 in the Small Magellanic Cloud (SMC), and SNR J0624–6948 in the Large Magellanic Cloud (LMC).

According to astronomers, there are two types of supernovae that can produce perfect SNR: supernovae caused by the core collapse of a red giant star, or type Ia supernovae - the result of the violent explosion of a smaller star. In the case of Telios, the type Ia hypothesis is considered more suitable, because red giant stars are very rare outside the galactic plane.

However, the researchers admit that there is currently no direct evidence to definitively determine the origin of Telios. “While we consider the Type Ia scenario to be the most likely, we note that no direct evidence can definitively confirm any of the scenarios and that new, high-resolution, sensitive observations of this object are needed,” the team stressed in their scientific paper.

Telios remains a great mystery in cosmology, requiring more observations and research to decipher its true shape, origin, and location.

Bao Ngoc (t/h)

Source: https://doanhnghiepvn.vn/cong-nghe/phat-heen-qua-cau-vu-tru-gan-nhu-hoan-ha-an-minh-duoi-mat-phang-ngan-ha-bi-an-ve-kich-thuoc-va-khoang-cach/20250523034727604