Far-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A

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Science  07 Jun 1996:
Vol. 272, Issue 5267, pp. 1459-1461
DOI: 10.1126/science.272.5267.1459


Far-infrared hydrogen recombination lines H15α (169.4 micrometers), H12α (88.8 micrometers), and H10α (52.5 micrometers) were detected in the peculiar luminous star MWC 349A from the Kuiper Airborne Observatory. Here it is shown that at least H15α is strongly amplified, with the probable amplification factor being greater than or about equal to 103 and a brightness temperature that is greater than or about equal to 107 kelvin. The other two lines also show signs of amplification, although to a lesser degree. Beyond H10α the amplification apparently vanishes. The newly detected amplified lines fall into the laser wavelength domain. These lasers, as well as the previously detected hydrogen masers, may originate in the photoionized circumstellar disk of MWC 349A and constrain the disk's physics and structure.