An international group of astrophysicists has discovered a giant space laser in the Ant Nebula. Such an astrophysical object is rather unusual, since it has signs of a planetary nebula, the physical conditions in which are not suitable for the emission of coherent photons. The results of scientific work were published in the Monthly Notices of the Royal Astronomical Society. The text of the article can be found in the arXiv preprint repository.
The Ant Nebula, or Menzel 3 (Mz 3), is a planetary nebula of a complex structure, which is located in the constellation of the Angle and belongs to bipolar, that is, it has the shape of two lobes. Its exact origin is still unknown, but a number of scientists believe that in the center of the nebula there may be a binary symbiotic star, one component of which pulls on the substance of the other. Thus, Mz 3 occupies an intermediate position between a young planetary nebula and a binary star, since it has the distinctive features of both objects.
Data from the Herschel Space Observatory showed that Menzel 3 contains 12 hydrogen recombination lines that occur in the infrared to submillimeter wavelength range. Such lines arise during quantum transitions between highly excited states of recombined hydrogen, when electrons newly captured by the hydrogen ion begin to jump into low-energy orbits and emit photons.
According to scientists, bright recombination lines are very unusual for planetary nebulae, in the spectrum of which there are mainly forbidden spectral lines corresponding to unlikely transitions of electrons. Thus, the detected lines cannot be explained by spontaneous emission, which is emitted by thin gas clouds of planetary nebulae.
However, similar ratios of spectral line intensities were observed in the object MWC 349A HRL - a massive binary (or, probably, triple) star, which is a natural cosmic laser, that is, a source of coherent photons. Like Menzel 3, it is surrounded by a bipolar nebula generated by streams of gas and a dense disk in the center. The source of laser radiation is a highly ionized (due to intense X-ray radiation) surface at the edge of the gas disk. The researchers concluded that the Ant Nebula, which has similar structure and physical conditions, is also a giant laser.