# Exoplanets Expert

> Expert-level exoplanet science covering detection methods, orbital dynamics, planetary atmospheres, habitability, and the search for biosignatures.

- Skill: `luokai0/exoplanets-expert` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add luokai0/exoplanets-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/luokai0/exoplanets-expert/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: luokai0 (https://skillmd.com/u/luokai0)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/luokai0/exoplanets-expert

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# Exoplanets Expert

## Before Starting
1. Detection, characterization, or habitability focus?
2. Which detection method?
3. Small rocky planets or giant planets?

## Core Expertise Areas

### Detection Methods
Transit: planet crosses star, flux decreases by Rp squared over Rs squared, period from timing.
Radial velocity: Doppler shift of stellar lines, measures m sin i.
Direct imaging: high contrast, wide-separation planets, young or massive targets.
Microlensing: brightening when planet-star system passes near background star.
Astrometry: stellar wobble in position, Gaia promising for long-period planets.

### Atmospheric Characterization
Transmission spectroscopy: during transit, starlight through atmosphere reveals absorption features.
Emission spectroscopy: secondary eclipse, thermal emission from planet measured directly.
Phase curves: full orbit photometry, day-night temperature contrast.
JWST: revolutionary sensitivity for small planet atmospheres, TRAPPIST-1 prime targets.

### Planetary Populations
Fulton gap: bimodal radius distribution at 1.5 to 2 Earth radii from photoevaporation.
Hot Jupiters: close-in giant planets, migrated from outer disk.
Super-Earths: 1 to 4 Earth radii, most common type found by Kepler.
Occurrence rates: Kepler statistics, eta-Earth for solar-type stars.

### Habitability
Habitable zone: range of orbital distances for surface liquid water.
M dwarf habitability: tidal locking, stellar flares, atmospheric erosion concerns.
Biosignatures: O2 plus CH4 disequilibrium, O3 UV shield, N2O from biology.
False positives: abiotic O2 from photolysis of CO2, careful context needed.

## Best Practices
- Combine multiple detection methods for complete planet characterization
- Account for detection biases when inferring occurrence rates
- Consider host star properties when assessing habitability
- Validate atmospheric detections against multiple spectral features

## Common Pitfalls
| Pitfall | Fix |
|---|---|
| Confusing equilibrium temperature with surface temperature | Greenhouse effect raises surface temperature significantly |
| Single biosignature as detection | Multiple independent lines of evidence needed |
| Ignoring stellar variability in transit analysis | Starspots can mimic or mask transit signals |
| Earth-centric habitability only | Other types of planets may support life |

## Related Skills
- planetary-science-expert
- astrophysics-expert
- cosmology-expert