They discover an enigmatic stellar object that defies the physics of neutron stars
Radio astronomy has made it possible to detect a new type of stellar object. A mysterious object that astronomers say “challenges our understanding of the physics of neutron stars” (a neutron star is what is left behind when a massive supergiant star runs out of fuel, collapses, and explodes as a supernova).
This new source of radio waves has been named GPM J183910 and is located 15,000 light years from Earth, in the constellation Scutum.. Astronomers still do not know the nature of this intriguing object, but this Wednesday they present in the journal Nature what they have been able to find out so far and their hypotheses.
As explained by this international team in which Spanish scientists from the Institute of Space Sciences (ICE-CSIC) participate, “the radio waves emitted by the object, the longest ever detected, suggest that it could be a magnetar or of a white dwarf star.
As detailed in a press release, an ultralong-period magnetar is a rare type of neutron star with extremely strong magnetic fields that can produce strong bursts of energy.. However, they have a second hypothesis: that it is actually a magnetic white dwarf, that is, an advanced stage in the life of a star similar to the Sun.. But none of the current scenarios for those objects, they add, can explain with certainty all the characteristics of this new source of radio waves: it emits radio waves every 21 minutes and, if interpreted as a pulsar, would be the longest-period radiomagnetar. long detected to date, set until recently, magnetars were observed to rotate in periods of a few seconds.
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Hidden in plain sight, the object GPM J183910 was discovered thanks to the Murchison Widefield Array (MWA) radio telescope, an astronomical facility located in the outback of Western Australia, in an aboriginal territory called Wajarri Yamaji.
They used the Gran Telescopio Canarias
The research has been led by Curtin University and the International Center for Radio Astronomy Research (ICRAR).. Spaniards Nanda Rea and Francesco Coti Zelati, from the Institute of Space Sciences, led follow-up observations of this new object using the Gran Telescopio Canarias (GTC), which is on La Palma and is the world's largest optical telescope.. They also used ESA's XMM-Newton X-ray telescope, and coordinated the physical interpretation of the results.
As reported by the CSIC, “it is the second long-periodic radio object detected and observed, for the first time, at all wavelengths in 2022 by ICE-CSIC researchers. However, the first discovered long-period radio emitter was transient and only shone in the sky for a few months.. Instead, this new source can be located in observation files dating back to 1988.”
“Discovering two systems of this type in such a short time tells us that they are very common in the universe,” says Nanda Rea, second author of the study, professor at ICE-CSIC and member of the Institut d'Estudis Espacials de Catalunya (IEEC) and second author of the study. “This rare object could challenge our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the universe,” said study lead author Natasha Hurley-Walker.
In January 2022, they published a paper in Nature describing an enigmatic transient object that appeared and disappeared intermittently, emitting strong beams of energy three times an hour. Between July and September of that same year, the team scanned the sky using the MWA telescope. Those of the Indian Giant Metrewave Radio Telescope (GMRT) and the American Very Large Array (VLA) had records of observations dating back to 1988.. That is, pulses from this object had been recorded for the first time 33 years ago, but no one noticed and they had remained hidden.
Not all pulsars produce radio waves. Some are thought to lie below the so-called 'death line', a critical threshold where a star's magnetic field becomes too weak to accelerate the particles responsible for radio waves.
Now this team of astronomers hopes to discover more periodic radio bursts in the future, which could help to finally understand the nature of these enigmatic objects.