Key parameters at a glance

A radius of 8.59 Earth radii
A mass of 55.30 Earth masses
Surface gravity around 0.75 g
An orbital period of 25.800 days
Semi-major axis 0.1800 AU
Distance from Earth 123.22 light-years
Earth Similarity Index 0.338
Travel time at Voyager 1 speed 2,172,906 years

HD 117618 b Planet Profile

Physical Specs

Radius

8.59 R⊕

Radius (Jupiter)

0.766 R♃

Mass

55.30 M⊕

Mass (Jupiter)

0.174 M♃

Density

0.48 g/cm³

Surface Gravity

0.75 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.338

HZ Position Unknown

Controversial No

Discovery

Year 2004

Method Radial Velocity

Facility Anglo-Australian Telescope

Telescope 3.9 m Anglo-Australian Telescope

Size rank in cohort

Rank by radius

#114of 574

top 19.7%

This planet

8.59R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

OGLE-2014-BLG-1722L b 8.59 R⊕ Kepler-1513 b 8.59 R⊕ HATS-49 b 8.57 R⊕

Metric	Earth	HD 117618 b	Jupiter
Radius (R⊕)	1.00	8.59	11.21
Mass (M⊕)	1.00	55.30	317.83
Density (g/cm³)	5.51	0.48	1.33
Surface Gravity (g)	1.00	0.75	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	55.302 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 117618

HIP

HIP 66047

TIC

TIC 243194645

Gaia DR2

Gaia DR2 6083860761505899904

Gaia DR3

Gaia DR3 6083860761505899904

System

HD 117618

Percentile among Neptune-like cohort

Radius 8.590 R⊕ · percentile 80 / cohort 574

Mass 55.302 M⊕ · percentile 75 / cohort 574

Orbital period 25.80 d · percentile 56 / cohort 524

Distance 37.78 pc · percentile 11 / cohort 572

ESI 0.338 · percentile 60 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

25.800 days

Semi-major axis

0.1800 AU

Eccentricity

0.150

Inclination

— °

Year Length

A year here lasts approximately 25.80 Earth days (7.1% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1800 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.338

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Tinney et al. 2005

Instrument

UCLES Spectrograph

Publication

2005-04

Observation locale

Ground

Discovery cohort

Planets confirmed in 2004 at Anglo-Australian Telescope (3 shown).

HD 154857 b · Gas Giant HD 208487 b · Gas Giant HD 160691 c · Unclassified

Host System: HD 117618

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,990 K — hotter than the Sun (5,778 K)

Estimated Age

5.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.200 R☉

Stellar Mass

1.077 M☉

Metallicity [Fe/H]

0.03

Extended Stellar Properties

Surface gravity (log g)

4.410 dex

Stellar density

0.933 g/cm³

Systemic radial velocity

1.28 km/s

Rotational v·sin i

3.20 km/s

Metallicity ratio

[M/H]

Distance

37.78 parsec

Light-years 123.22 ly

V-band magnitude

7.17 mag

Voyager-speed travel 2,172,906 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

26.442 mas

Total Proper Motion

127.945 mas/yr

PM Right Ascension

25.25 mas/yr

PM Declination

-125.43 mas/yr

Galactic Cartesian (pc)

x = -0.624 · y = -0.266 · z = -0.735

Equatorial (J2000)

RA 203.10664° · Dec -47.27190°

Galactic ℓ, b

310.111° · 15.028°

Ecliptic λ, β

220.681° · -34.614°

HTM-20 index

-466466844

Observation Record

Photometric series

RV measurements

Archive notes