(NLDO) - A radio observatory operating in the Western Australian desert has picked up a very strange signal from a place 4,000 light years away from Earth.
According to Science Alert , a mysterious incident happened to the Murchison Widefield Array (MWA) - a radio astronomy observatory in the Western Australian desert. It was a flashing signal like a pulsar, but between extremely long pulses there was an extremely long time.
The incident happened several years ago, but at the time, no scientist could explain the source of the signal.
They only knew that it must be a kind of world never known before.
A pair of red dwarf and pulsar white dwarf stars may be emitting a mysterious type of radio signal - Graphic: ESO
Dubbed GLEAM-X J162759.5−523504.3, the mysterious source was described as emitting radio waves for 30 to 60 seconds, every 18.18 minutes, until March 2018, when it stopped.
But then a series of signals that were just as strange hit the MWA in 2023, from another part of the sky that was crowded with celestial objects.
The second mysterious source emits five-minute radio bursts every 22 minutes. When archival data was reviewed, it was found to have been active since at least 1988.
This second mysterious source is called GPM J1839-10.
Scientists tried to find similar data in the observatory's archives, and they found a third signal.
Dubbed GLEAM-X J0704-37, the third mysterious source emits a signal lasting 30-60 seconds every 2.9 hours. It is located on the outskirts of Earth’s Milky Way galaxy in the southern constellation of Pupa.
This third signal is easier to observe than the two similar signals mentioned above.
So, a research team led by astrophysicist Natasha Hurley-Walker from the International Centre for Radio Astronomy Research (ICRAR) at Curtin University (Australia) decided to focus on this third mysterious source.
They used the MeerKAT radio telescope array in South Africa to zoom in on the sky where the signal originated and found just one faint star that matched that location.
Analysis of the star's spectrum revealed its identity: an M-type red dwarf.
However, red dwarfs are very common in the Milky Way and other red dwarfs do not produce such a signal.
The team searched for something that could explain the anomaly and found that it was most likely a white dwarf, the remaining core of a collapsed Sun-like star.
According to a paper published in The Astrophysical Journal Letters , this binary star system may consist of a red dwarf with a mass of about 0.32 times the mass of the Sun and a white dwarf with a mass of 0.8 times the mass of the Sun.
But because it is a compact object, the size of a white dwarf will be much smaller.
If both are in close enough orbit, the white dwarf may be accreting material from the red dwarf, resulting in continuous jets of emission from the white dwarf's poles.
So this white dwarf is actually GLEAM-X J0704-37, the one that emitted the strange signal.
This also makes it a pulsar white dwarf, a type of white dwarf with the capabilities of a pulsar, which is typically a more powerful form of neutron star.
It is also one of the rarest types of stars in the Milky Way. GLEAM-X J162759.5−523504.3 and GPM J1839-10 may be the only two remaining known representatives of this type of star.
Source: https://nld.com.vn/theo-tin-hieu-radio-la-dai-thien-van-uc-tim-ra-dieu-khong-tuong-196241216091943456.htm
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