# Subaru/SCExAO First-Light Direct Imaging of a Young Debris Disk around HD 36546

## TL;DR

This paper reports the first direct imaging of a young debris disk around HD 36546 using Subaru/SCExAO, revealing its structure, orientation, and potential planetary influences, and discusses its implications for understanding early planet formation.

## Contribution

First high-contrast imaging of a debris disk around HD 36546 with SCExAO, providing detailed disk morphology and constraints on potential planets, and suggesting its status as possibly the youngest debris disk imaged.

## Key findings

- Disk extends from 34 to 114 au with a near east-west orientation.
- Disk is inclined at 70-75 degrees and is strongly forward-scattering.
- No planets above 23 au with masses comparable to HR 8799 b are detected.

## Abstract

We present $H$-band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by the HiCIAO camera using the vector vortex coronagraph. SCExAO traces the disk from $r$ $\sim$ 0.3" to $r$ $\sim$ 1" (34--114 au). The disk is oriented in a near east-west direction (PA $\sim$ 75$^{o}$), is inclined by $i$ $\sim$ 70--75$^{o}$ and is strongly forward-scattering ($g$ $>$ 0.5). It is an extended disk rather than a sharp ring; a second, diffuse dust population extends from the disk's eastern side. While HD 36546 intrinsic properties are consistent with a wide age range ($t$ $\sim$ 1--250 $Myr$), its kinematics and analysis of coeval stars suggest a young age (3--10 $Myr$) and a possible connection to Taurus-Auriga's star formation history. SCExAO's planet-to-star contrast ratios are comparable to the first-light Gemini Planet Imager contrasts; for an age of 10 $Myr$, we rule out planets with masses comparable to HR 8799 b beyond a projected separation of 23 au. A massive icy planetesimal disk or an unseen superjovian planet at $r$ $>$ 20 au may explain the disk's visibility. The HD 36546 debris disk may be the youngest debris disk yet imaged, is the first newly-identified object from the now-operational SCExAO extreme AO system, is ideally suited for spectroscopic follow up with SCExAO/CHARIS in 2017, and may be a key probe of icy planet formation and planet-disk interactions.