Science and Nature

Antimatter Stars Might possibly well maybe Be Lurking in Milky Method

Astronomers the utilization of files from NASA’s Fermi Gamma-ray Plan Telescope indulge in identified 14 candidate antistars — stars fabricated from antimatter — in our Milky Method Galaxy.

An artist’s impression of an antimatter star. Image credit:

An artist’s influence of an antimatter star. Describe credit:

“We typically remove it as a accurate that equal quantities of matter and antimatter had been produced within the Enormous Bang, yet the observable Universe seems to contain finest negligible quantities of antimatter,” said Simon Dupourque from the College of Toulouse’s Institute for Compare in Astrophysics and Planetology and colleagues.

“Baryonic antimatter in our Describe voltaic and Galactic neighborhood will even be constrained by the observation of high-energy gamma rays.”

“When coming into contact with long-established matter, it might maybe well probably maybe assassinate annihilation radiation featuring a characteristic spectrum peaking around half of the mass of the unbiased pion and with a cutoff at some level of the mass of the proton.”

“The non-detection of this annihilation characteristic in gamma rays has almost excluded the existence of corpulent quantities of baryonic antimatter within the Describe voltaic Machine, the Describe voltaic neighborhood, the Milky Method, and as much as the scale of galaxy clusters.”

This has been recently challenged by the detection of some antihelium nuclei by the Alpha Magnetic Spectrometer experiment (AMS-02) on the Worldwide Plan Negate.

“AMS-02 measures roughly one antihelium in a hundred million helium,” the researchers explained.

“Amongst the eight antihelium events reported, six are love minded with being antihelium-3 and two with antihelium-4.”

“A couple of authors had identified that ‘the detection of a single antihelium […] would be a smoking gun […] for the existence of antistars and of antigalaxies’.”

Within the fresh glance, the scientists analyzed records from the gamma-ray offer catalog (4FGL-DR2) produced by the Fermi Important Plan Telescope (LAT).

“4FGL-DR2 is in accordance to 10 years of observations with the LAT within the facility vary from 50 MeV to 1 TeV,” they said.

“It contains 5,787 gamma-ray sources with their spectral parameters, spectral energy distributions, mild curves, and multiwavelength associations.”

Positions and energy flux in the 100 MeV-100 GeV range of antistar candidates selected in 4FGL-DR2. The background image shows the Fermi 5-year all-sky photon counts above 1 GeV. Image credit: NASA / DOE / Fermi LAT Collaboration / Dupourqué et al., doi: 10.1103/PhysRevD.103.083016.

Positions and energy flux within the 100 MeV-100 GeV vary of antistar candidates selected in 4FGL-DR2. The background image presentations the Fermi 5-twelve months all-sky photon counts above 1 GeV. Describe credit: NASA / DOE / Fermi LAT Collaboration / Dupourqué et al., doi: 10.1103/PhysRevD.103.083016.

They had been in a suite to isolate 14 candidate stars whose properties had been spectrally love minded with the anticipated signal from matter-antimatter annihilation.

“Alternatively, the persona of these sources is quiet unsure. It’s much extra doubtless that they are in reality other sorts of well-established gamma-ray emitters, much like pulsars or gloomy holes,” they illustrious.

The authors moreover estimated that in our Milky Method Galaxy, there are 2.5 antistars per one million customary stars.

“The antistars extra doubtless to be detected by the LAT lie at distances between about a tens of parsecs to 1,000 parsecs, and due to the this fact might maybe be the identical antistars producing the antihelium nuclei tentatively detected by AMS-02,” they said.

“Alternatively, translating quantitatively the constraints on the antistar populations to the processes at on initiating place of the AMS-02 antihelium would require making hypotheses on the mechanisms that eject and escape antinuclei from antistars.”

A paper describing the findings became published within the journal Bodily Review D.


Simon Dupourqué et al. 2021. Constraints on the antistar allotment within the Describe voltaic Machine neighborhood from the 10-twelve months Fermi Important Plan Telescope gamma-ray offer catalog. Phys. Rev. D 103 (8): 083016; doi: 10.1103/PhysRevD.103.083016

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