Exoplanet

HD 219666 b

Orbiting HD 219666

Overview

HD 219666 b is an exoplanet orbiting the star HD 219666, discovered in 2018 using the Transit method. It is a Neptune-sized world.

Key Measurements

Radius

4.90

Earth radii

015 R⊕

Mass

17.60

Earth masses

0500 M⊕

Orbital Period

6.0

days

0.1d10,000d

Distance

94.2

parsecs

Nearby10,000 pc

Equilibrium Temp

1076

K

150 K3,500 K

Radius (Earth radii)

4.90

Mass (Earth masses)

17.60

Measured

Equilibrium Temperature

1076 K

Parameter source: Murphy et al. 2025

Orbital Period

6.034+0.000−0.000days

Planet Mass (Earth masses)

17.60+1.20−1.20

Planet Mass (Jupiter masses)

0.0550+0.0030−0.0030

Eccentricity

0.0500+0.0400−0.0400

Argument of Periastron

0.0+48.0−48.0deg

Radial Velocity Semi-Amplitude

6.07+0.32−0.32m/s

Distance from Earth

94.2 pc (~307 ly)

Spectral Type

Unknown

Temperature

5540 K

Mass (Solar)

1.02 M☉

Radius (Solar)

1.06 R☉

Luminosity

Unknown

Planets in System

1

Stars in System

1

Coordinates (RA, Dec)

349.5593°, -56.9040°

Discovery Method

Transit

Discovery Year

2018

Data Sources
NASA Exoplanet Archive

Source ID: HD 219666 b

System Context

HD 219666 b orbits HD 219666 and was reported in 2018 and was detected with the Transit method.

Published measurements list a radius of 4.9 Earth radii, a mass of 17.6 Earth masses, an orbital period of 6.03 days, and an equilibrium temperature near 1,076 K.

Catalog data places the system at about 94.2 parsecs from Earth 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 HD 219666