Embedded Star Formation in the Eagle Nebula

M16=NGC 6611, the Eagle Nebula, is a well studied region of star formationand the source of a widely recognized Hubble Space Telescope (HST) image. Highspatial resolution infrared observations with the Near Infrared Camera andMulti-Object Spectrometer (NICMOS) on HST reveal the detailed morphology of twoembedded star formation regions that are heavily obscured at opticalwavelengths. It is striking that only limited portions of the visually obscuredareas are opaque at 2.2 microns. Although the optical images imply substantialcolumns of material, the infrared images show only isolated clumps of dense gasand dust. Rather than being an active factory of star production, only a fewregions are capable of sustaining current star formation. Most of the volume inthe columns may be molecular gas and dust, protected by capstones of densedust. Two active regions of star formation are located at the tips of the opticalnorthern and central large ``elephant trunk'' features shown in the WFPC2images. They are embedded in two capstones of infrared opaque material thatcontains and trails behind the sources. Although the presence of these sourceswas evident in previous observations at the same and longer wavelengths, theNICMOS images provide a high resolution picture of their morphology. Two brightstars appear at the tip of the southern column and may be the result of recentstar formation at the top of that column. These observations suggest that theepoch of star formation in M16 may be near its endpoint.Comment: Accepted by the Astrophysical Journa