NICMOS Photometry of the Unusual Dwarf Planet Haumea and its Satellites

TL;DR

This study uses HST NICMOS observations to analyze the water-ice features and surface properties of the dwarf planet Haumea and its satellites, revealing insights into their composition and formation history.

Contribution

First infrared photometry of Haumea and its satellites, showing water-ice absorption features and surface variations linked to a collisional origin.

Findings

Water-ice absorption features are at least as deep on satellites as on Haumea.

Haumea's light-curve shows a bluer infrared color at the red spot.

Satellites likely formed from the same collision event as Haumea.

Abstract

We present here HST NICMOS F110W and F160W observations of Haumea, and its two satellites Hi'iaka and Namaka. From the measured (F110W-F160W) colours of -1.209 +/-0.004, -1.48 +/- 0.06, and -1.4 +/- 0.2 mag for each object, respectively, we infer that the 1.6 imcron water-ice absorption feature depths on Hi'iaka and Namaka are at least as deep as that of Haumea. The light-curve of Haumea is detected in both filters, and we find that the infrared colour is bluer by approximately 2-3% at the phase of the red spot. These observations suggest that the satellites of Haumea were formed from the collision that produced the Haumea collisional family.