We present Keck/NIRC2 K _ { s } band high-contrast coronagraphic imaging of the luminous debris disk around the nearby , young A star HD 32297 resolved at a projected separation of r = 0.3–2.5″ ( \approx 35–280 AU ) .
The disk is highly warped to the north and exhibits a complex , “ wavy ” surface brightness profile interior to r \approx 110 AU , where the peaks/plateaus in the profiles are shifted between the NE and SW disk lobes .
The SW side of the disk is 50–100 % brighter at r = 35–80 AU , and the location of its peak brightness roughly coincides with the disk ’ s mm emission peak .
Spectral energy distribution modeling suggests that HD 32297 has at least two dust populations that may originate from two separate belts likely at different locations , possibly at distances coinciding with the surface brightness peaks .
A disk model for a single dust belt including a phase function with two components and a 5–10 AU pericenter offset explains the disk ’ s warped structure and reproduces some of the surface brightness profile ’ s shape ( e.g .
the overall “ wavy ” profile , the SB peak/plateau shifts ) but more poorly reproduces the disk ’ s brightness asymmetry and the profile at wider separations ( r > 110 AU ) .
Although there may be alternate explanations , agreement between the SW disk brightness peak and disk ’ s peak mm emission is consistent with an overdensity of very small , sub-blowout-sized dust and large , 0.1–1 mm-sized grains at \approx 45 AU tracing the same parent population of planetesimals .
New near-IR and submm observations may be able to clarify whether even more complex grain scattering properties or dynamical sculpting by an unseen planet are required to explain HD 32297 ’ s disk structure .