# Which planet is most like Earth?

## Result

Changing the value function changes the winner. The equal-weighted ranking favors
**Teegarden's Star b**; emphasizing Earth-like size
and equilibrium temperature favors **Wolf 1069 b**;
and emphasizing proximity favors **Proxima Cen b**.

The archive snapshot contains **6,366** confirmed planets. Radius is usable
for **6,311**, equilibrium temperature for **5,829**,
distance for **6,338**, and all three for **5,763**.

## Winner and tie audit

- **Size Only**: 8 winner(s) — EPIC 201833600 c, EPIC 206215704 b, K2-229 b, K2-239 c, Kepler-1417 b, Kepler-1464 c, Kepler-392 b, TOI-2267 b
- **Temperature Only**: 1 winner(s) — HD 40307 g
- **Distance Only**: 2 winner(s) — Proxima Cen b, Proxima Cen d
- **Balanced**: 1 winner(s) — Teegarden's Star b
- **Earth Analog**: 1 winner(s) — Wolf 1069 b
- **Exploration Distance**: 1 winner(s) — Proxima Cen b
- **Size First**: 1 winner(s) — Proxima Cen b
- **Temperature First**: 1 winner(s) — Wolf 1069 b

The size-only result is therefore an eight-way tie, not a unique win. Several
planets also tie on distance because planets in the same stellar system share
the same system distance. Composite profiles have unique winners in this snapshot.

## Scoring

- Size deviation: `abs(ln(radius / 1 R_earth))`
- Temperature deviation: `abs(ln(T_eq / 255 K))`
- Distance: archive system distance in parsecs
- Combined criteria are percentile-ranked over complete cases.
- Balanced: 1/3 each.
- Earth analogue: 45% size, 45% temperature, 10% distance.
- Exploration distance: 15%, 15%, 70%.
- Size first: 70%, 15%, 15%.
- Temperature first: 15%, 70%, 15%.
- Lower scores are better. Exact ties use minimum rank.

## Interpretation

These are rankings of three archive fields, not habitability estimates.
Equilibrium temperature is a black-body model rather than surface temperature.
Radius can be measured or model-derived. Distance measures accessibility, not
biological suitability. Atmospheres, stellar activity, composition, water,
mass, tidal state, and parameter uncertainty are not included.

The PSCompPars table has one relatively complete row per confirmed planet, but
its composite parameters may come from different references and need not form
a self-consistent physical solution.

## Reproduction

From the package root:

```sh
python -m pip install -r requirements.txt
python code/analyze_rankings.py
```

The script reads only the preserved raw CSV and regenerates the calculated
table, rankings, tie audit, figures, and this report.
