Using Astrocladistics in Small Body research: The Jovian Trojans
Abstract
Astrocladistics is a recently developed technique that has been used to analyse a variety of astronomical objects, from galaxies to the satellite systems of the giant planets. The method borrows from biology, the 'Tree of Life', to examine the relationships between various astronomical objects. In this work, we apply the novel astrocladistical method to the Jovian Trojan population. The Jovian Trojans are two swarms of small Solar system bodies that are located at the Lagrange points of Jupiter. These objects represent a test case for astrocladistics, as they include several collisional families, as well as a history dating back to the early Solar system. The population is also due to visited by the Lucy spacecraft, launching in 2021. The astrocladistical method begins with the creation of a 2d matrix. For each object, in this case, the Jovian Trojans, a set of binned characteristics are used. We used the proper orbital and libration dynamical characteristics, albedo, density, and color ratios where available. The color ratios are sourced from multiple datasets, including SDSS, WISE, Gaia DR2, and the MOVIS survey. Not all Trojans are present in each survey and these are accounted for in the algorithm, highlighting one of the advantages of astrocladistics, its use in incomplete datasets. We do limit the selection for this study to those Jovian Trojans that have colors in at least one survey, creating two matrices, one for each of the L4 and L5 swarms. The result are dendritic trees, visualising the relationships between the Jovian Trojans. Here we present the results of astrocladistical analysis performed on the two Jovian Trojan swarms. Each swarm can be split into many clans and several superclans. Some of these clans correlate with previously identified collisional families, and the limited number of taxonomic classes identified in the swarms. In analysing the Jovian Trojan swarms, we highlight the advantages of astrocladistics, further validating its applicability to the planetary sciences. The example of the Jovian Trojans provides a basis for the use of astrocladistics in future analyses of larger populations of small Solar system bodies.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.295H