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 330.000 days
Semi-major axis 0.8900 AU
Distance from Earth 132.04 light-years
Earth Similarity Index 0.320
Travel time at Voyager 1 speed 2,328,549 years

HD 137388 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 2011

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO 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 218566 b 9.32 R⊕ HD 220197 b 9.32 R⊕

Metric	Earth	HD 137388 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 137388

HIP

HIP 76351

TIC

TIC 407090552

Gaia DR2

Gaia DR2 5778418870846853888

Gaia DR3

Gaia DR3 5778418870846853888

System

HD 137388

Percentile among Neptune-like cohort

Radius 9.320 R⊕ · percentile 90 / cohort 574

Mass 63.566 M⊕ · percentile 81 / cohort 574

Orbital period 330.00 d · percentile 94 / cohort 524

Distance 40.48 pc · percentile 12 / cohort 572

ESI 0.320 · percentile 55 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

330.000 days

Semi-major axis

0.8900 AU

Eccentricity

0.360

Inclination

— °

Year Length

A year here lasts approximately 330.00 Earth days (90.3% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.8900 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.320

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Dumusque et al. 2011

Instrument

HARPS Spectrograph

Publication

2011-11

Observation locale

Ground

Discovery cohort

Planets confirmed in 2011 at La Silla Observatory (10 shown).

GJ 433 b · Sub-Neptune HD 20794 d · Sub-Neptune HD 192310 b · Neptune-like HD 20794 b · Super-Earth HD 7449 b · Gas Giant HD 192310 c · Neptune-like HD 217786 b · Gas Giant HIP 5158 c · Gas Giant HD 204941 b · Gas Giant HD 7199 b · Unclassified

Host System: HD 137388

Spectral Class

K-type orange

Effective Temperature

5,181 K — cooler than the Sun (5,778 K)

Estimated Age

6.45 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.880 R☉

Stellar Mass

0.680 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

4.390 dex

Stellar density

1.711 g/cm³

Systemic radial velocity

26.01 km/s

Rotational v·sin i

4.00 km/s

Metallicity ratio

[Fe/H]

Distance

40.48 parsec

Light-years 132.04 ly

V-band magnitude

8.71 mag

Voyager-speed travel 2,328,549 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

24.672 mas

Total Proper Motion

64.415 mas/yr

PM Right Ascension

-49.57 mas/yr

PM Declination

41.13 mas/yr

Galactic Cartesian (pc)

x = -0.100 · y = -0.137 · z = -0.985

Equatorial (J2000)

RA 233.91508° · Dec -80.20442°

Galactic ℓ, b

309.743° · -19.582°

Ecliptic λ, β

259.050° · -58.148°

HTM-20 index

305292619

Similar Worlds

HD 218566 b

Neptune-like · K-type orange

Radius 9.32 R⊕ · 94.0 ly

HD 33142 d

Neptune-like · K-type orange

Radius 9.32 R⊕ · 395.9 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 La Silla Observatory Mission K-type orange Hosts