Infrared Observations of the Quintuplet Proper Members with SOFIA/FORCAST and Gemini/TreCS

We present 19.7, 25.2, 31.5, and 37.1 micron observations of the Quintuplet proper members (with an angular resolution of 3.2-3.8”) taken with the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST) in conjunction with archival high-resolution (∼0.1-0.2”) mid-infrared images from the Thermal-Region Camera Spectrograph (TReCS). Since their discovery, the Quintuplet proper members have been somewhat mysterious in nature. Originally dubbed the “cocoon stars” due to their cool featureless spectra, high-resolution near-infrared imaging observations have shown that at least two of the objects exhibit “pinwheel” nebulae consistent with binary systems with a carbon rich Wolf-Rayet star and O/B companion. In this work, we aim to characterize the dust reservoirs in these systems to constrain the total dust mass and study any changes in the mass-loss rates for each object. DUSTY models of the thermal dust emission of two of the objects, Q2 and Q3, are well fit by radial density profiles which are consistent with constant mass loss rates. For, the two remaining sources, Q1 and Q9, extended structures (∼ 1”) are detected around these objects in high-resolution imaging data. Based on the fitted dust masses, Q9 has an unusually large dust reservoir (~1.3E-3 M☉) compared to typical dusty Wolf-Rayet stars which suggests that it may have recently undergone an episode of enhanced mass loss. The results of this work have been published in ApJ, 827, 136 (2016).