Simulate dual-body planet-moon light curve dips (CD-35 2722), stellar limb darkening & biosignature spectra.
Bottom Line Up Front (BLUF): Space observatories detect exoplanets by measuring subtle periodic drops in stellar flux. The discovery of exomoons (such as the CD-35 2722 system) is confirmed when secondary transit ingress/egress shoulders occur alongside the primary planetary dip, accompanied by barycentric Transit Timing Variations (TTV).
When a primary planet and its exomoon both transit the stellar disk without overlapping along the line of sight, the total relative flux drop is proportional to the combined cross-sectional area:
| System Name | Host Star Type | Planet Radius | Exomoon Radius | Transit Depth (ppm) | Classification |
|---|---|---|---|---|---|
| CD-35 2722 B | M-Dwarf (3700 K) | 11.2 R⊕ (Jupiter) | 9.5 R⊕ (Saturn-size) | ~4,290 ppm | Binary Exomoon |
| HS 0209+0832 | White Dwarf (11,500 K) | 8.5 R⊕ | None | ~38,000 ppm | Phoenix World |
| Earth Twin | G2V Solar (5778 K) | 1.0 R⊕ | 0.27 R⊕ (Luna) | ~84 ppm | Habitable Zone |
| TRAPPIST-1e | M8V Ultra-Cool (2566 K) | 0.92 R⊕ | None | ~4,900 ppm | Temperate Rocky |
During transit, starlight filters through the planetary atmospheric annulus. Chemical species absorb distinct wavelengths: ozone (O3 at 9.6 μm) and methane (CH4 at 3.3 μm) together signal biological thermodynamic disequilibrium.
Stars are spherical radiators where optical depth allows us to peer into deeper, hotter layers at the center of the disk than near the outer limb, producing the curved ingress and egress profiles.