In an intriguing development in the field of astronomy, a team of scientists has identified a star exhibiting unprecedented behavior, shedding light on a new category of enigmatic celestial objects. This discovery, made possible by combining data from NASA’s Chandra X-ray Observatory and the Square Kilometer Array Pathfinder (ASKAP) radio telescope in Australia, offers fresh insights into the mysterious nature of these cosmic phenomena.
The object in question, identified as ASKAP J1832−0911, or ASKAP J1832 for short, is part of a group known as “long period radio transients.” These objects are characterized by their unique ability to change in radio wave intensity over extended periods, specifically tens of minutes. This duration is significantly longer than the variations observed in pulsars, which are rapidly rotating neutron stars that exhibit multiple intensity changes every second. Specifically, ASKAP J1832 shows a notable cycle in its radio wave intensity every 44 minutes, firmly placing it in the long period radio transient category.
Utilizing Chandra, researchers discovered that ASKAP J1832 also experiences fluctuations in X-rays at the same 44-minute interval. This marks the first instance of an X-ray signal being detected in a long period radio transient, adding another layer of intrigue to this cosmic puzzle.
To create a comprehensive image of the object, scientists combined X-ray data from Chandra (depicted in blue) with infrared data from NASA’s Spitzer Space Telescope (represented by various shades of blue, teal, and orange), and radio data from LOFAR (shown in red). An inset provides a closer look at the area surrounding this exceptional object in both X-ray and radio light.
Over a span of six months, the team observed ASKAP J1832’s X-ray and radio wave emissions decrease dramatically. This combination of a 44-minute cycle in both X-rays and radio waves, along with these longer-term variations, is unprecedented in the Milky Way galaxy.
The research team suggests that ASKAP J1832 is unlikely to be a pulsar or a typical neutron star accreting material from a companion star, as its properties deviate from the known radio and X-ray intensities of these objects. Some characteristics of ASKAP J1832 could potentially be explained by a neutron star with an extraordinarily strong magnetic field, known as a magnetar, with an age exceeding half a million years. However, the bright and variable radio emissions of ASKAP J1832 present a challenge to this hypothesis, as they are atypical for a magnetar of such age.
Interestingly, ASKAP J1832 appears to be located within a supernova remnant, the aftermath of an exploded star, which frequently contains a neutron star formed by the supernova. Nevertheless, the research team believes this proximity is likely coincidental, suggesting that ASKAP J1832 does not house a neutron star. Instead, they propose that a white dwarf with a companion star could be responsible for the emissions, although this would require the strongest magnetic field ever recorded for a white dwarf in our galaxy.
The findings of this research, led by Ziteng Wang from Curtin University in Australia, have been published in the journal Nature. Independently, a team led by Di Li from Tsinghua University in China also discovered this source using the DAocheng Radio Telescope and submitted their findings to arXiv simultaneously. However, their research did not report the X-ray behavior observed by Wang’s team.
The Chandra X-ray Observatory program is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center handles science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
For those interested in exploring more about the Chandra X-ray Observatory and its mission, additional information can be accessed through NASA’s official websites.
Visual Description:
In the released images, two composite visuals showcase the enigmatic object, potentially an unusual neutron star or white dwarf, situated near the edge of a supernova remnant. The entity, known as ASKAP J1832, has captivated astronomers from both the Chandra X-ray Observatory and the Square Kilometre Array Pathfinder radio telescope with its peculiar and unpredictable behavior.
The primary composite image situates the mysterious object within the context of the surrounding supernova remnant and nearby gas clouds. In this image, radio data is represented in red, and X-ray sources detected by Chandra are displayed in dark blue. The supernova remnant appears as a large, wispy, red oval ring occupying the lower right section of the image. ASKAP J1832 resides within this ring, slightly to the right of the center, depicted as a tiny purple spot amidst a sea of colorful specks. The gas cloud is shown using infrared data from NASA’s Spitzer Space Telescope, resembling a mottled green, teal blue, and golden orange cloud occupying the upper left half of the square image.
A secondary close-up image provides a detailed view of the immediate vicinity around ASKAP J1832. In this composite image, the infrared data from Spitzer is removed, eliminating the mottled cloud and most of the colorful background specks. Near the inside edge of the hazy red ring, the object appears as a bright white dot with a hot pink outer edge, set against the blackness of space. Upon closer inspection, the hot pink edge reveals three faint spikes extending from its surface.
Both the primary and close-up images are presented without adornments and with labels, including fine white circles highlighting ASKAP J1832.
This remarkable discovery underscores the complexity and richness of the universe, prompting further investigation and exploration. As astronomers continue to unravel the mysteries of ASKAP J1832, the scientific community and the public alike remain keenly interested in the potential revelations this enigmatic object may hold.
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