![Kepler-102 b: 0.46 Times Earth](https://cdn.slatesource.com/b/3/6/b36d8f89-edb8-4d36-8b6b-56e072b24e5c.webp)

# Kepler-102 b: 0.46 Times Earth

- [Made in Slatesource](https://slatesource.com/@steph/kepler-102-b-0-46-times-earth)
- By [Steph](https://slatesource.com/@steph)
- Created on Sep 19, 2026

## Terrestrial around Kepler-102

It is 0.46 times Earth's radius, closest in size to Mars, and 1.1 times Earth's mass, at 62.00 g/cm3, denser than Earth. A year there lasts 5.29 days, on an orbit 7 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 857 K, hot enough to melt lead. The host star Kepler-102 runs at 4909 K with 0.80 times the Sun's mass.

journey·5 Planets

# Kepler-102 from the inside out

Orbit

/

Planet

"terrestrial, 857 K.

"terrestrial, 777 K.

"terrestrial, 686 K.

"mini-Neptune, 590 K.

"terrestrial, 495 K.

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

Radius

0.46 Earth radii

Mass

1.1 Earth masses

Equilibrium temperature

857 K (measured)

One year

5.29 days

Orbit radius

0.0552 AU

Host star

Kepler-102 at 4909 K

Distance

352 light-years

Starlight blocked

0.003% at each transit

🔭🪐📅01.01.2013 – 01.01.2014

01.01.2013Kepler-102 e

01.01.2013

01.01.2014Kepler-102 b, Kepler-102 c, Kepler-102 d, Kepler-102 f

01.01.2014

What you get from the shadow

Block a known fraction of a known star and you have measured a width.

Found by Kepler in 2014. Kepler's method needed repetition, not brightness. It could find small planets around faint stars, provided they came round quickly enough to be seen twice.

Kepler-102 has 5 known planets. A crowded system is worth more than the sum of its planets: the timing of each transit constrains the others.

Two independent measurements sit behind this page: a dip in starlight for the size, and something else entirely for the mass. Together they make a density.

[NASA Exoplanet Archive: the full record for Kepler-102 b](https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-102%20b?utm_source=slatesource)