This mixed-series chart compares planetary diameter (bar) and orbital period (line) for 15 objects. A dual-axis layout uses a left scale for diameter and a right scale for orbital days, with the line positioned at bar centers. Built with D3 v7, it loads CSV data via `d3.csv`, applies `d3.scaleBand` and `d3.scaleLinear`, and renders SVG bars, a `d3.line` with `curveMonotoneX`, and circles. A legend distinguishes the metrics.