Time-Resolved Near-Infrared Photometry of Extreme Kuiper Belt Object Haumea

TL;DR

This study provides detailed near-infrared photometry of Haumea, revealing surface color variations, a notably blue satellite, and wavelength-dependent phase behavior, enhancing understanding of its surface composition and rotational properties.

Contribution

It presents new time-resolved near-infrared data of Haumea, identifying surface color heterogeneity and the distinct spectral properties of its satellite, advancing knowledge of Kuiper Belt object surfaces.

Findings

Near-infrared photometric range similar to visible wavelengths.

Detected surface color variations correlated with specific regions.

Hi'iaka satellite is significantly bluer in J-H than Haumea.

Abstract

We present time-resolved near-infrared (J and H) photometry of the extreme Kuiper belt object (136108) Haumea (formerly 2003 EL61) taken to further investigate rotational variability of this object. The new data show that the near-infrared peak-to-peak photometric range is similar to the value at visible wavelengths, \Delta m_R = 0.30+/-0.02 mag. Detailed analysis of the new and previous data reveals subtle visible/near-infrared color variations across the surface of Haumea. The color variations are spatially correlated with a previously identified surface region, redder in B-R and darker than the mean surface. Our photometry indicates that the J-H colors of Haumea (J-H=-0.057+/-0.016 mag) and its brightest satellite Hi'iaka (J-H=-0.399+/-0.034 mag) are significantly (>9 sigma) different. The satellite Hi'iaka is unusually blue in J-H, consistent with strong 1.5 micron water-ice absorption. The phase coefficient of Haumea in the J-band is found to increase monotonically with wavelength in the range 0.4<lambda<1.3. We compare our findings with other Solar system objects and discuss implications regarding the surface of Haumea.