2008 OG$_{19}$: A highly elongated Trans-Neptunian Object

TL;DR

This study presents detailed photometric analysis of the Trans-Neptunian Object 2008 OG$_{19}$, revealing its elongated shape, rotation period, size, and density estimates based on observational data and hydrostatic equilibrium assumptions.

Contribution

First detailed light curve analysis of 2008 OG$_{19}$, providing its rotation period, shape, size, and density estimates, highlighting its highly elongated nature.

Findings

Rotation period of 8.727 hours.

Object is highly elongated, similar to Varuna.

Estimated diameter of approximately 619 km.

Abstract

From two observing runs during the 2014 summer at Calar Alto Observatory in Almer\'ia (Spain) and at Sierra Nevada Observatory in Granada (Spain), we were able to derive CCD photometry of the Trans-Neptunian Object 2008 OG$_{19}$. We analyzed the time series and obtained a double-peaked light curve with a peak to valley amplitude of (0.437 $\pm$ 0.011) mag and a rotational period of (8.727$\pm$ 0.003) h. This implies that this object is very elongated, closely resembling Varuna's case. The photometry also allowed us to obtain an absolute magnitude in R-band of (4.39 $\pm$ 0.07) mag. From this result we estimated an equivalent diameter of 2008 OG$_{19}$ which is 619$^{+56}_{-113}$ km using an average albedo for Scattered Disk Objects. Finally we interpreted the results under the assumption of hydrostatic equilibrium and found a lower limit for the density of 544$^{+42}_{-4}$ kg$\,$m$^{-3}$. However, a more likely density is (609 $\pm$ 4) kg$\,$m$^{-3}$ using an aspect angle of 60$^\circ$, which corresponds to the most likely configuration for the spin axis with respect to the observer assuming random orientations.