An international team of astronomers led by scientists from the University of Manchester discovered unusual laser radiation in the Ant Nebula while studying data from the European Space Agency's (ESA) Herschel Space Telescope. The extremely rare occurrence suggests a binary star system hidden in the heart of the nebula, Phys.org reports, citing research published in the Monthly Notices of the Royal Astronomical Society.
When stars of low to medium mass - roughly the size of our Sun - approach the end of their lives, they first transform into red giants, which then dump their outer layers of gas and dust into space, creating a kaleidoscope with intricate patterns - a planetary nebula. Only the core remains of the star: it becomes a dense white dwarf. Our Sun is expected to one day form such a planetary nebula - an interstellar cloud of dust, hydrogen, helium and other ionized gases.
The Ant Nebula in the constellation Nagonika got this bizarre name due to its unusual shape: it consists of two lobes that resemble the head and body of an ant. Recent observations by the Herschel telescope have shown that the dramatic death of the central star in the Ant Nebula is even more theatrical and colorful than previously thought. New data show that intense laser radiation is emitting from the center of the Ant Nebula. Lasers are widely used in various fields of human activity: they are used to create special visual effects at music concerts, as well as, for example, in medicine. In space, the laser show is detected at very different wavelengths and only under certain conditions. Only a few cases of cosmic "representations" are known.
Coincidence: Astronomer Donald Menzel, who first observed and described the planetary Ant nebula in the 1920s (then named Menzel 3), was also one of the first to suggest that, under certain conditions, the natural "amplification of light by stimulated emission" (light amplification by stimulated emission of radiation - "laser" is an acronym for this combination), can occur in nebulae in space.
The scientists stressed that they have discovered a very rare type of laser radiation - which comes from the recombination of hydrogen atoms, which can only occur in a very limited range of physical conditions. Recombination is the reverse process of ionization: an atom captures free electrons.
Comparison of observations with computer models showed that the density of the gas in the nebula from which the laser radiation emanates is about ten thousand times denser than the gas observed in typical planetary nebulae and in the lobes of the Ant nebula itself. Usually, the region close to a dead star (in this case, roughly equal to the distance from Saturn to the Sun) is rather empty because its material is pushed outward. The only case when such a dense gas is preserved near a star is if it revolves around it "on the disk". In the Ant Nebula, astronomers actually observed a dense disk at the very center - the so-called accretion disk. This structure usually occurs around stars in close binaries. The discovered disc in the Ant Nebula suggeststhat the central dying star has a companion - the star alone would have a hard time pushing the ejected gas into orbit, since there would be no companion to deflect the gas in the right direction. So far, however, astronomers have not seen the expected second star hidden in the heart of the Ant Nebula.