Reflected-Light Contrast Budgets for Earth and Jupiter Analogues at One to Ten Parsecs

This study computes a detection budget for a clearly bounded question: How faint is a planet in reflected starlight, expressed as a planet-to-star flux ratio, and how does that ratio interact with the angular resolution of present and planned telescopes? An Earth twin at 1 au gives a contrast of 1.732e-10, or 97.6 dB below its star. Placing the same planet at 0.8 au raises the contrast to 2.706e-10, a factor of about 1.6 gained purely from geometry. A Jupiter analogue moved inward to 1 au reaches 3.615e-08; at its true 5.2 au distance it falls to 1.337e-09. All values are computed from published anchor values and stated assumptions by a deposited script; the study is simulated and computed throughout, not measured. Reflected-light contrasts span 1e-7 to below 1e-10 across the standard target list, and the Earth-twin value of about 1.2e-10 is the binding requirement.