Key parameters at a glance

A radius of 9.32 Earth radii
A mass of 63.57 Earth masses
Surface gravity around 0.73 g
An orbital period of 225.700 days
Semi-major axis 0.6900 AU
Distance from Earth 94.02 light-years
Earth Similarity Index 0.320
Travel time at Voyager 1 speed 1,658,083 years

HD 218566 b Planet Profile

Physical Specs

Radius

9.32 R⊕

Radius (Jupiter)

0.832 R♃

Mass

63.57 M⊕

Mass (Jupiter)

0.200 M♃

Density

0.43 g/cm³

Surface Gravity

0.73 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.320

HZ Position Unknown

Controversial No

Discovery

Year 2010

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#55of 574

top 9.4%

This planet

9.32R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

HD 33142 d 9.32 R⊕ HD 137388 b 9.32 R⊕ HD 220197 b 9.32 R⊕

Metric	Earth	HD 218566 b	Jupiter
Radius (R⊕)	1.00	9.32	11.21
Mass (M⊕)	1.00	63.57	317.83
Density (g/cm³)	5.51	0.43	1.33
Surface Gravity (g)	1.00	0.73	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	63.566 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 218566

HIP

HIP 114322

TIC

TIC 278952345

Gaia DR2

Gaia DR2 2638410646295370880

Gaia DR3

Gaia DR3 2638410646295370880

System

HD 218566

Percentile among Neptune-like cohort

Radius 9.320 R⊕ · percentile 90 / cohort 574

Mass 63.566 M⊕ · percentile 81 / cohort 574

Orbital period 225.70 d · percentile 91 / cohort 524

Distance 28.83 pc · percentile 9 / cohort 572

ESI 0.320 · percentile 55 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

225.700 days

Semi-major axis

0.6900 AU

Eccentricity

0.300

Inclination

— °

Year Length

A year here lasts approximately 225.70 Earth days (61.8% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.6900 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

8.300 m/s

Transit mid-time (BJD)

2,454,667.4000

Long. of periastron (ω)

44.00°

Angular separation (arcsec)

23.90000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.320

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Meschiari et al. 2011

Instrument

HIRES Spectrometer

Publication

2011-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2010 at W. M. Keck Observatory (12 shown).

HD 156668 b · Super-Earth HD 1461 b · Sub-Neptune GJ 876 e · Sub-Neptune HAT-P-17 c · Gas Giant HD 97658 b · Sub-Neptune HD 163607 c · Gas Giant HD 177830 c · Neptune-like HD 102956 b · Gas Giant HD 163607 b · Gas Giant GJ 1148 b · Gas Giant HD 31253 b · Gas Giant HD 164509 b · Gas Giant

Host System: HD 218566

Spectral Class

K-type orange

Effective Temperature

4,730 K — cooler than the Sun (5,778 K)

Estimated Age

8.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.850 R☉

Stellar Mass

0.760 M☉

Metallicity [Fe/H]

0.28

Extended Stellar Properties

Surface gravity (log g)

4.460 dex

Stellar density

2.028 g/cm³

Systemic radial velocity

-37.66 km/s

Rotational v·sin i

0.00 km/s

Metallicity ratio

[Fe/H]

Distance

28.83 parsec

Light-years 94.02 ly

V-band magnitude

8.60 mag

Voyager-speed travel 1,658,083 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

34.660 mas

Total Proper Motion

638.959 mas/yr

PM Right Ascension

631.52 mas/yr

PM Declination

-97.21 mas/yr

Galactic Cartesian (pc)

x = 0.975 · y = -0.220 · z = -0.039

Equatorial (J2000)

RA 347.29742° · Dec -2.26116°

Galactic ℓ, b

74.017° · -55.109°

Ecliptic λ, β

347.430° · 2.935°

HTM-20 index

-633699905

Observation Record

Photometric series

RV measurements

Stellar spectra

Similar Worlds

HD 33142 d

Neptune-like · K-type orange

Radius 9.32 R⊕ · 395.9 ly

HD 137388 b

Neptune-like · K-type orange

Radius 9.32 R⊕ · 132.0 ly

V1298 Tau b

Neptune-like · K-type orange

Radius 9.41 R⊕ · 352.9 ly

TOI-4600 c

Neptune-like · K-type orange

Radius 9.42 R⊕ · 704.7 ly

Kepler-695 b

Neptune-like · K-type orange

Radius 9.21 R⊕ · 2,749.3 ly

HD 104067 b

Neptune-like · K-type orange

Radius 9.20 R⊕ · 66.4 ly

Explore Related Categories

Neptune-like Planets Radial Velocity Discoveries W. M. Keck Observatory Mission K-type orange Hosts