Lightcurves of 32 Large Transneptunian Objects

TL;DR

This study observes 32 Transneptunian objects, analyzing their lightcurves to understand their rotational properties, correlations with size and dynamical class, and comparing findings with existing data.

Contribution

It provides new lightcurve data for 32 TNOs, identifies correlations between amplitude and magnitude, and highlights differences among dynamical populations.

Findings

Fitted periods and amplitudes for 15 objects.

Found a correlation between lightcurve amplitude and absolute magnitude.

Classical objects tend to have larger amplitude lightcurves than Scattered objects.

Abstract

We present observations of 32 primarily bright, newly discovered Transneptunian objects observable from the Southern Hemisphere during 39 nights of observation with the 2.5-m telescope at Las Campanas Observatory. Our dataset includes objects in all dynamical classes, but is weighted towards Scattered objects. We find 15 objects for which we can fit periods and amplitudes to the data, and place lightcurve amplitude upper limits on the other 17 objects. Combining our sample with the larger sample in the literature, we find a 3-sigma correlation between lightcurve amplitude and absolute magnitude with fainter objects having larger lightcurve amplitudes. We looked for correlations between lightcurve and individual orbital properties, but did not find any statistically significant results. However, if we consider lightcurve properties with respect to dynamical classification, we find statistically different distributions between the Classical-Scattered and Classical-Resonant populations, respectively, with the Classical objects having larger amplitude lightcurves. The properties of binary lightcurves are largely consistent with the greater population except in the case of tidally locked systems. All the Haumea family objects measured so far have measurable amplitudes and rotation periods le 10 hr suggesting that they are not significantly different from the larger TNO population. We expect multiple factors are influencing object rotations: object size dominates lightcurve properties except in the case of tidal, or proportionally large collisional interactions with other objects, the influence of the latter being different for each sub-population. We also present phase curves and colors for some objects; our values are not significantly different from those presented in the literature for other samples.