Bringing "The Moth" to Light: A Planet-Sculpting Scenario for the HD 61005 Debris Disk

TL;DR

This study proposes that an eccentric, inclined planet can explain the unique features of the HD 61005 debris disk, supported by new high-resolution imaging and modeling that align with observed morphology.

Contribution

The paper introduces a planet-sculpting scenario for the HD 61005 debris disk, supported by detailed imaging and secular perturbation modeling, offering a new explanation for its unusual features.

Findings

Disk shaped by a planet with eccentricity ≥ 0.2

Parent body population at 40-52 AU

Possible planet mass ranges from Earth to Jupiter

Abstract

The HD 61005 debris disk ("The Moth") stands out from the growing collection of spatially resolved circumstellar disks by virtue of its unusual swept-back morphology, brightness asymmetries, and dust ring offset. Despite several suggestions for the physical mechanisms creating these features, no definitive answer has been found. In this work, we demonstrate the plausibility of a scenario in which the disk material is shaped dynamically by an eccentric, inclined planet. We present new Keck NIRC2 scattered-light angular differential imaging of the disk at 1.2-2.3 microns that further constrains its outer morphology (projected separations of 27-135 AU). We also present complementary Gemini Planet Imager 1.6 micron total intensity and polarized light detections that probe down to projected separations less than 10 AU. To test our planet-sculpting hypothesis, we employed secular perturbation theory to construct parent body and dust distributions that informed scattered-light models. We found that this method produced models with morphological and photometric features similar to those seen in the data, supporting the premise of a planet-perturbed disk. Briefly, our results indicate a disk parent body population with a semimajor axis of 40-52 AU and an interior planet with an eccentricity of at least 0.2. Many permutations of planet mass and semimajor axis are allowed, ranging from an Earth mass at 35 AU to a Jupiter mass at 5 AU.