2008ApJ...684L..41D

We report HST NICMOS coronagraphic images of the HD 15115 circumstellar disk at 1.1 µm. 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 µm 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 µm 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 µm at 1", 2", and 3". At 2" the western lobe has a neutral spectrum up to 1.1 µm and a strong absorption or blue spectrum >1.1 µm, while a blue trend is seen in the eastern lobe. At 1" the disk has a red F110W-H color in both lobes.