Program: GN-2011A-Q-64

Among the most luminous objects in the Quintuplet Cluster are five dust-embedded stars, the Quintuplet sources themselves, whose natures were a mystery until recent high resolution infrared imaging of several of them revealed pinwheel like nebulae surrounding them. This suggests that these objects are binaries producing dust in highly energetic and massive colliding winds, such as those produced by Wolf-Rayet stars. The bright infrared spectra of the Quintuplet sources had previously been found to be featureless and characteristic of thermal emission by hot dust. Recently, however, we discovered that the H band spectrum of one of the Quintuplet sources contains a faint and very broad line at 1.7 microns, likely due to helium. This is the first emission line detected from any of these stars. Based on this discovery we request time to obtain accurate J and H band spectra of the Quintuplet sources. In the J band the objects are much fainter than at H (due to foreground extinction), but the thermal emission from dust will be much weaker, which should mean the intrinsic spectra of central stars will be relatively much more prominent and enable us to be able to strongly constrain the spectral type of each source.