Key parameters at a glance

A radius of 2.77 Earth radii
A mass of 8.10 Earth masses
Surface gravity around 1.06 g
An orbital period of 60.722 days
Semi-major axis 0.2560 AU
Distance from Earth 58.02 light-years
Earth Similarity Index 0.667
Travel time at Voyager 1 speed 1,023,158 years

1 sibling around HIP 38594

HIP 38594 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HIP 38594 b this	Sub-Neptune	2.77	8.10	60.722	—	2020
HIP 38594 c	Neptune-like	7.94	48.40	3,477.768	—	2020

HIP 38594 b Planet Profile

Physical Specs

Radius

2.77 R⊕

Radius (Jupiter)

0.247 R♃

Mass

8.10 M⊕

Mass (Jupiter)

0.025 M♃

Density

2.09 g/cm³

Surface Gravity

1.06 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.667

HZ Position Unknown

Controversial No

Discovery

Year 2020

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#780of 1978

top 39.4%

This planet

2.77R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-251 c 2.77 R⊕ Kepler-251 d 2.77 R⊕ TOI-444 b 2.77 R⊕

Metric	Earth	HIP 38594 b	Jupiter
Radius (R⊕)	1.00	2.77	11.21
Mass (M⊕)	1.00	8.10	317.83
Density (g/cm³)	5.51	2.09	1.33
Surface Gravity (g)	1.00	1.06	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	8.100 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 38594

TIC

TIC 128902569

Gaia DR2

Gaia DR2 5602386058511578368

Gaia DR3

Gaia DR3 5602386058511578368

System

HIP 38594

Percentile among Sub-Neptune cohort

Radius 2.770 R⊕ · percentile 60 / cohort 1978

Mass 8.100 M⊕ · percentile 55 / cohort 1978

Orbital period 60.72 d · percentile 89 / cohort 1946

Distance 17.79 pc · percentile 4 / cohort 1975

ESI 0.667 · percentile 90 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

60.722 days

Semi-major axis

0.2560 AU

Eccentricity

0.170

Inclination

— °

Year Length

A year here lasts approximately 60.72 Earth days (16.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.2560 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.667

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Feng et al. 2020

Instrument

Multiple Instruments

Publication

2020-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2020 at Multiple Observatories (12 shown).

GJ 3473 c · Sub-Neptune HD 216520 c · Sub-Neptune HD 216520 b · Sub-Neptune HIP 107772 b · Sub-Neptune GJ 480 b · Sub-Neptune HIP 4845 b · Sub-Neptune HD 190007 b · Neptune-like GJ 687 c · Neptune-like GJ 2056 b · Neptune-like HD 238090 b · Sub-Neptune HIP 48714 b · Neptune-like HIP 38594 c · Neptune-like

Host System: HIP 38594

Spectral Class

M-type red dwarf

Effective Temperature

4,086 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.627 R☉

Stellar Mass

0.610 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

4.629 dex

Stellar density

3.491 g/cm³

Systemic radial velocity

62.88 km/s

Distance

17.79 parsec

Light-years 58.02 ly

V-band magnitude

9.75 mag

Voyager-speed travel 1,023,158 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

56.187 mas

Total Proper Motion

361.820 mas/yr

PM Right Ascension

-300.91 mas/yr

PM Declination

200.92 mas/yr

Galactic Cartesian (pc)

x = -0.432 · y = 0.794 · z = -0.427

Equatorial (J2000)

RA 118.54391° · Dec -25.30231°

Galactic ℓ, b

242.401° · 1.297°

Ecliptic λ, β

127.711° · -45.075°

HTM-20 index

1015383714