Color gradients detected in the HD 15115 circumstellar disk

We report HST NICMOS coronagraphic images of the HD 15115 circumstellar disk at 1.1 mm. We find a similar morphology to that seen in the visible and at H band-an edge-on disk that is asymmetric in surface brightness. Several aspects of the 1.1 mu m data are different, highlighting the need for multiwavelength images of each circumstellar disk. We find a flattening to the western surface brightness profile at 1.1 mu m interior to 2 '' ( 90 AU) and a warp in the western half of the disk. We measure the surface brightness profiles of the two disk lobes and create a measure of the dust scattering efficiency between 0.55 and 1.65 mu m at 1 '', 2 '', and 3 ''. At 2 '' the western lobe has a neutral spectrum up to 1.1 mu m and a strong absorption or blue spectrum 11.1 mu m, while a blue trend is seen in the eastern lobe. At 1 '' the disk has a red color in both lobes.