The Gemini NICI Planet-Finding Campaign: Asymmetries in the HD 141569 disc

TL;DR

This study presents high-resolution near-infrared imaging of the HD 141569A disc, revealing detailed asymmetries and structures such as rings, arcs, and potential offsets, enhancing understanding of its morphology and possible planetary influences.

Contribution

The paper provides the highest resolution near-IR images of HD 141569A's disc, resolving inner structures and asymmetries not seen in previous HST data, and suggests possible inner companions.

Findings

Inner ring/spiral feature is not circular after deprojection.

Outer ring is brighter on the western side but appears circular after deprojection.

An arc-like feature connects the inner and outer rings on the east side.

Abstract

We report here the highest resolution near-IR imaging to date of the HD 141569A disc taken as part of the NICI Science Campaign. We recover 4 main features in the NICI images of the HD 141569 disc discovered in previous HST imaging: 1) an inner ring / spiral feature. Once deprojected, this feature does not appear circular. 2) an outer ring which is considerably brighter on the western side compared to the eastern side, but looks fairly circular in the deprojected image. 3) an additional arc-like feature between the inner and outer ring only evident on the east side. In the deprojected image, this feature appears to complete the circle of the west side inner ring and 4) an evacuated cavity from 175 AU inwards. Compared to the previous HST imaging with relatively large coronagraphic inner working angles (IWA), the NICI coronagraph allows imaging down to an IWA of 0.3". Thus, the inner edge of the inner ring/spiral feature is well resolved and we do not find any additional disc structures within 175 AU. We note some additional asymmetries in this system. Specifically, while the outer ring structure looks circular in this deprojection, the inner bright ring looks rather elliptical. This suggests that a single deprojection angle is not appropriate for this system and that there may be an offset in inclination between the two ring / spiral features. We find an offset of 4+-2 AU between the inner ring and the star center, potentially pointing to unseen inner companions.