Strange Pulsar Dwarfs - An Explanation of Long-Period Radio Phenomena?

Scientists have proposed an explanation for a mysterious class of radio phenomena known as "ultra-long-period radio transients," the Chinese Academy of Sciences announced.

Ultra-long-period radio transients (ULPTs) are a class of astrophysical objects with rotation periods reaching thousands of seconds, significantly different from the typical pulsar periods of milliseconds to tens of seconds.

Pulsars, or rotating neutron stars, emit radiation (usually radio) toward us at very regular intervals. This works in a similar way to how a lighthouse works—the pulsar rotates and the beam of radiation sweeps our direction periodically.

According to the standard theory describing these objects, if a pulsar spins very slowly, its rotational energy is insufficient to produce radio emission. Therefore, radio pulsars with such long periods should not exist. However, recently discovered sources such as GLEAM-X J1627-52 and GPM J1839-10 contradict this principle, raising challenges to the current theory.

The topic is a subject of scientific debate; many ideas have been proposed to explain this mystery, including magnetars, strongly magnetic white dwarfs, radio-emitting white dwarfs, some type of disk, exotic stellar interactions, and hot subdwarfs. However, each of these hypotheses has certain difficulties in explaining all the properties of the phenomenon.

Researchers from a group led by Professor Zhou Xia of the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences have a new idea. They propose that this class of phenomena is caused by objects they call "strange dwarf pulsars." These are compact objects with strange matter (quark matter) at their cores, surrounded by a shell of ordinary matter. These objects have larger radii than ordinary pulsars.

Strange matter is a type of matter composed of strange particles—that is, particles that contain a strange quark. Physicists know several types of quarks, one of which they have named the strange quark. Strange quarks occur in some elementary particles produced in Earth's laboratories (in particle accelerators).

"Strange dwarfs" were first proposed in 1995. Unlike ordinary "white dwarfs," the mechanisms within them are related to the strange matter hypothesis (quark matter), as opposed to the physics behind the stable existence of white dwarfs. "Strange dwarfs" (or more broadly: strange stars, quark stars) are hypothetical objects, but calculations show that they can exist in stable configurations.

The scientists successfully applied their model to four cosmic sources: GLEAM-X J1627-52, GPM J1839-10, ASKAP J1832-0911, and ASKAP J193505.1+214841.0. In the future, they plan to use the FAST radio telescope and the currently developed Square Kilometer Array (SKA) radio telescope network to test the new model observationally.

The research results were presented in an article published in The Astrophysical Journal. (PAP)

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