![Kepler-406 b: 11.8 Grams Per Cubic Centimetre](https://cdn.slatesource.com/a/1/1/a11022ed-fd41-4673-bffb-1bf6345bd7d5.webp)

# Kepler-406 b: 11.8 Grams Per Cubic Centimetre

- [Made in Slatesource](https://slatesource.com/@steph/kepler-406-b-11-8-grams-per-cubic-centimetre)
- By [Steph](https://slatesource.com/@steph)
- Created on Sep 19, 2026

## Super-earth around Kepler-406

It is 1.43 times Earth's radius, closest in size to Earth, and 6.3 times Earth's mass, at 11.82 g/cm3, denser than Earth. A year there lasts 2.43 days. The host star Kepler-406 runs at 5538 K with 1.07 times the Sun's mass.

**11.8** g/cm3: denser than iron at Earth surface pressure

Radius

1.43 Earth radii

Mass

6.3 Earth masses

One year

2.43 days

Host star

Kepler-406 at 5538 K

Distance

1187 light-years

Starlight blocked

0.015% at each transit

Known and unknown, as the archive has it

0%

A size. Yes.

A mass. Yes.

A density, so rock and gas can be told apart. Yes.

A semi-major axis. No.

An observed temperature. No.

An eccentricity, so we know if the orbit is a circle. No.

What the transit gives

How deep the star dims fixes the planet's size relative to it.

A transit gives the radius and a separate measurement gives the mass. Having both is what makes a density, and a density is the only clue to composition at this range.

Found by Kepler in 2014. Kepler stared at one patch of sky for four years, which is why so many of its planets have short periods: a planet only counts once you have seen it cross several times.

Kepler-406 has 2 known planets. Systems like this are the ones where architecture can be studied instead of guessed at.

[NASA Exoplanet Archive: every published measurement of this planet](https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-406%20b?utm_source=slatesource)