Key parameters at a glance

A radius of 3.53 Earth radii
A mass of 12.21 Earth masses
Surface gravity around 0.98 g
An orbital period of 105.911 days
Semi-major axis 0.3430 AU
Distance from Earth 19.28 light-years
Earth Similarity Index 0.585
Travel time at Voyager 1 speed 339,963 years

HD 180617 b Planet Profile

Physical Specs

Radius

3.53 R⊕

Radius (Jupiter)

0.315 R♃

Mass

12.21 M⊕

Mass (Jupiter)

0.038 M♃

Density

1.53 g/cm³

Surface Gravity

0.98 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.585

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Radial Velocity

Facility Calar Alto Observatory

Telescope 3.5 m telescope

Size rank in cohort

Rank by radius

#164of 1978

top 8.2%

This planet

3.53R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-359 b 3.53 R⊕ K2-285 c 3.53 R⊕ Kepler-1038 b 3.53 R⊕

Metric	Earth	HD 180617 b	Jupiter
Radius (R⊕)	1.00	3.53	11.21
Mass (M⊕)	1.00	12.21	317.83
Density (g/cm³)	5.51	1.53	1.33
Surface Gravity (g)	1.00	0.98	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	12.214 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 180617

HIP

HIP 94761

TIC

TIC 176188045

Gaia DR2

Gaia DR2 4293318823182081408

Gaia DR3

Gaia DR3 4293318823182081408

System

HD 180617

Percentile among Sub-Neptune cohort

Radius 3.530 R⊕ · percentile 92 / cohort 1978

Mass 12.214 M⊕ · percentile 85 / cohort 1978

Orbital period 105.91 d · percentile 94 / cohort 1946

Distance 5.91 pc · percentile 0 / cohort 1975

ESI 0.585 · percentile 81 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

105.911 days

Semi-major axis

0.3430 AU

Eccentricity

0.101

Inclination

— °

Year Length

A year here lasts approximately 105.91 Earth days (29.0% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.3430 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.585

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Kaminski et al. 2018

Instrument

CARMENES

Publication

2018-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2018 at Calar Alto Observatory (2 shown).

GJ 1265 b · Sub-Neptune GJ 3779 b · Sub-Neptune

Host System: HD 180617

Spectral Class

M-type red dwarf

Effective Temperature

3,534 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.481 R☉

Stellar Mass

0.484 M☉

Metallicity [Fe/H]

-0.04

Extended Stellar Properties

Surface gravity (log g)

4.900 dex

Stellar density

6.279 g/cm³

Systemic radial velocity

35.68 km/s

Rotational v·sin i

2.00 km/s

Rotation period

50.60 days

Metallicity ratio

[Fe/H]

Distance

5.91 parsec

Light-years 19.28 ly

V-band magnitude

9.12 mag

Voyager-speed travel 339,963 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

169.159 mas

Total Proper Motion

1,453.096 mas/yr

PM Right Ascension

-579.04 mas/yr

PM Declination

-1,332.74 mas/yr

Galactic Cartesian (pc)

x = 0.328 · y = -0.940 · z = 0.090

Equatorial (J2000)

RA 289.22773° · Dec 5.16316°

Galactic ℓ, b

40.441° · -3.284°

Ecliptic λ, β

291.630° · 27.170°

HTM-20 index

-1238642222

Observation Record

Photometric series

Stellar spectra

Archive notes