They have the smallest wavelengths and the most energy of any wave in the electromagnetic spectrum, making them difficult to detect. Gamma rays are a form of electromagnetic radiation produced by the hottest and most energetic objects in the universe.
Scientists had long suspected that recurrent novae may be the source of galactic cosmic radiation, but the recent observations showed the mechanism by which these explosions can cause gamma ray emissions. “The thermonuclear explosion is so powerful that a shockwave is generated expanding outwards - particle acceleration takes place at the front of these shocks,” Mitchell says. WHAT’S NEW - Using observations from its most recent outburst, the team behind the new study found that these stellar explosions create an environment for protons to accelerate to very high energies. RS Ophiuchi is one with a relatively small timeframe, with its last outburst having taken place in the year 2006. There are only 10 known recurrent novae where more than one outburst has been observed by astronomers. Recurrent novae are when a binary star system goes through repeated outbursts, increasing in brightness once every few decades. Nova outbursts occur when nuclear fusion is ignited on the surface of the white dwarf star, generating a thermonuclear explosion, or a rapid release of energy, that throws material outwards. Over time, the amount of accumulated matter that the white dwarf star has drawn from its companion increases, and the surface of the star heats up. DESY /H.E.S.S., Science Communication Lab
Material ejected from the surface of the white dwarf generates shockwaves that rapidly expand, forming an hour-glass shape. “But in novae, the star is not destroyed.” “In supernovae, the progenitor star is typically destroyed by the explosion, collapsing into a degenerate remnant,” Mitchell says. This causes the binary star system to shine up to a million times brighter than its normal luminosity. The white dwarf star, which is the dense core left over after a star has run out of fuel, begins to suck away the gas from its stellar companion. HERE’S THE BACKGROUND - Picture two stars entangled in a binary system, one of which has exhausted all of its nuclear fuel. Mitchell and colleagues detailed their findings in a study published Thursday in the journal Science. The reason why RS Ophiuchi is of interest is that the binary star system bursts out in repeated explosions, which could be a source of cosmic rays that bombard Earth from the Solar System.
“Typically the brightest novae are the most promising targets for us, and RS Ophiuchi was particularly bright - visible with the naked eye if you knew where to look.” “We have been trying to catch a nova for a long time,” Mitchell tells Inverse. On August 9, 2021, the recurrent nova RS Ophiuchi had a dramatic outburst, brightening seven magnitudes over a period of 24 hours.Īlison Mitchell, a researcher at the Erlangen Centre for Astroparticle Physics in Germany, and other members of the High Energy Stereoscopic System (H.E.S.S.) Collaboration were waiting for this cosmic explosion. A star that had been in hiding for 15 years suddenly reappeared in the skies.
0 kommentar(er)
