Multiband imaging of the HD 36546 debris disk: a refined view from SCExAO/CHARIS

Abstract

We present the first multi-wavelength (near-infrared; $1.1-2.4$ $\hat{I}¼m$) imaging of HD 36546's debris disk, using the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system coupled with the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS). As a 3-10 Myr old star, HD 36546 presents a rare opportunity to study a debris disk at very early stages. SCExAO/CHARIS imagery resolves the disk over angular separations of $\ddot{I}\sim 0.25"-1.0"$ (projected separations of ${\mathrm{r}}_{\mathrm{proj}}\sim 25-101$ $\mathrm{au}$) and enables the first spectrophotometric analysis of the disk. The disk's brightness appears symmetric between its eastern and western extents and it exhibits slightly blue near-infrared colors on average (e.g. $J-K=-0.4\pm 0.1$) $-$ suggesting copious sub-micron sized or highly porous grains. Through detailed modeling adopting a Hong scattering phase function (SPF), instead of the more common Henyey-Greenstein function, and using the differential evolution optimization algorithm, we provide an updated schematic of HD 36546's disk. The disk has a shallow radial dust density profile ($\hat{I}{\pm }_{in}\approx 1.0$ and $\hat{I}{\pm }_{out}\approx -1.5$), a fiducial radius of $r_0\approx 82.7$ au, an inclination of $i\approx 79.1^{\circ }$, and a position angle of $\mathrm{PA}\approx 80.1^{\circ }$. Through spine tracing, we find a spine that is consistent with our modeling, but also with a "swept-back wing" geometry. Finally, we provide constraints on companions, including limiting a companion responsible for a marginal Hipparcos-Gaia acceleration to a projected separation of $\lesssim 0.2^{\prime \prime }$ and to a minimum mass of $\lesssim 11$ ${\mathrm{M}}_{\mathrm{Jup}}$.

23 pages, 19 figures; corrected an error in the abstract, added a reference in Section 2