Mutual Orbits and Masses of Six Transneptunian Binaries

TL;DR

This study uses Hubble observations to determine the orbits and masses of six transneptunian binary systems, providing insights into their physical properties and the characteristics of the Cold Classical population.

Contribution

It presents new orbital and mass measurements for six transneptunian binaries, enhancing understanding of their physical properties and the Cold Classical subpopulation.

Findings

Orbital periods range from 22 to 137 days.

System masses range from 0.2 to 9.7 x 10^18 kg.

Albedos are higher for Cold Classical objects.

Abstract

We present Hubble Space Telescope observations of six binary transneptunian systems: 2000 QL251, 2003 TJ58, 2001 XR254, 1999 OJ4, (134860) 2000 OJ67, and 2004 PB108. The mutual orbits of these systems are found to have periods ranging from 22 to 137 days, semimajor axes ranging from 2360 to 10500 km, and eccentricities ranging from 0.09 to 0.55. These orbital parameters enable estimation of system masses ranging from 0.2 to 9.7 x 10+18 kg. For reasonable assumptions of bulk density (0.5 to 2.0 g cm-3), the masses can be combined with visible photometry to constrain sizes and albedos. The resulting albedos are consistent with an emerging picture of the dynamically "Cold" Classical subpopulation having relatively high albedos, compared with comparablysized objects on more dynamically excited orbits.