Exoplanet

GJ 3378 b

Orbiting GJ 3378

Overview

GJ 3378 b is an exoplanet orbiting the star GJ 3378, discovered in 2026 using the Radial Velocity method.

Key Measurements

Minimum Mass (M sin i)

2.30

Earth masses

0500 M⊕

Orbital Period

21.4

days

0.1d10,000d

Distance

7.7

parsecs

Nearby10,000 pc

Equilibrium Temp

272

K

150 K3,500 K

What these measurements mean

These comparisons use the reported catalog values. They are interpretations and calculations, not additional observations.

A year on this world
A 365.25-day Earth year spans about 17 of these orbits. This comparison uses the reported orbital period. It does not measure the planet's rotation or the length of its day.
What the mass can tell you
M sin i is a lower bound on the true mass because the viewing angle affects the radial-velocity measurement. Do not treat it as an exact mass or use it to claim a measured density.
Temperature has limits
Equilibrium temperature describes a model of absorbed and emitted energy, not a measured surface temperature. Atmosphere and reflectivity affect the interpretation. This value alone cannot establish liquid water, a habitable surface, or life.
Work through an exoplanet comparisonArchive measurement definitions

Radius (Earth radii)

Unknown

Minimum Mass, M sin(i) (Earth masses)

2.30

Radial-velocity minimum

Equilibrium Temperature

272 K

Parameter source: Robertson et al. 2026

Orbital Period

21.450+0.010−0.010days

Semi-Major Axis

0.0967+0.0008−0.0008au

M sin(i) (Earth masses)

2.30+0.40−0.40

M sin(i) (Jupiter masses)

0.0072+0.0013−0.0013

Eccentricity

0.0000

Radial Velocity Semi-Amplitude

1.30+0.20−0.20m/s

Distance from Earth

7.7 pc (~25 ly)

Spectral Type

M4 V

Temperature

3340 K

Mass (Solar)

0.26 M☉

Radius (Solar)

0.28 R☉

Luminosity

-2.07 log L☉

Planets in System

1

Stars in System

1

Coordinates (RA, Dec)

90.2951°, 59.5932°

Discovery Method

Radial Velocity

Discovery Year

2026

Data Sources
NASA Exoplanet Archive

Source ID: GJ 3378 b

System Context

GJ 3378 b orbits GJ 3378 and was reported in 2026 and was detected with the Radial Velocity method.

Published measurements list a minimum mass of 2.3 Earth masses (M sin i), an orbital period of 21.45 days, and an equilibrium temperature near 272 K.

Catalog data places the system at about 7.7 parsecs from Earth, a host star classified as M4 V, and 1 known planet in the system.

Host star

Explore the stellar record for this system to compare temperature, spectral type, and known planets.

Open GJ 3378