Key parameters at a glance

A radius of 13.20 Earth radii
A mass of 858.14 Earth masses
Surface gravity around 4.93 g
An orbital period of 578.600 days
Semi-major axis 1.4000 AU
Distance from Earth 380.28 light-years
Earth Similarity Index 0.389
Travel time at Voyager 1 speed 6,706,150 years

HD 40956 b Planet Profile

Physical Specs

Radius

13.20 R⊕

Radius (Jupiter)

1.180 R♃

Mass

858.14 M⊕

Mass (Jupiter)

2.700 M♃

Density

2.05 g/cm³

Surface Gravity

4.93 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.389

HZ Position Unknown

Controversial No

Discovery

Year 2017

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#847of 1771

top 47.8%

This planet

13.20R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 12661 c 13.20 R⊕ HD 37605 b 13.20 R⊕ MOA-2009-BLG-387L b 13.20 R⊕

Metric	Earth	HD 40956 b	Jupiter
Radius (R⊕)	1.00	13.20	11.21
Mass (M⊕)	1.00	858.14	317.83
Density (g/cm³)	5.51	2.05	1.33
Surface Gravity (g)	1.00	4.93	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	858.141 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 40956

HIP

HIP 28951

TIC

TIC 71099944

Gaia DR2

Gaia DR2 1008018211509401728

Gaia DR3

Gaia DR3 1008018211509401728

System

HD 40956

Percentile among Gas Giant cohort

Radius 13.200 R⊕ · percentile 49 / cohort 1771

Mass 858.141 M⊕ · percentile 63 / cohort 1747

Orbital period 578.60 d · percentile 70 / cohort 1533

Distance 116.59 pc · percentile 38 / cohort 1759

ESI 0.389 · percentile 82 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

578.600 days

Semi-major axis

1.4000 AU

Eccentricity

0.240

Inclination

— °

Year Length

A year here lasts about 1.58 Earth years on a mildly elliptical path at a mean orbital distance of 1.4000 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.389

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Jeong et al. 2018

Instrument

Multiple Instruments

Publication

2018-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2017 at Multiple Observatories (12 shown).

GJ 625 b · Super-Earth TRAPPIST-1 e · Rocky Terrestrial TRAPPIST-1 f · Rocky Terrestrial TRAPPIST-1 g · Rocky Terrestrial TRAPPIST-1 h · Rocky Terrestrial HD 34445 e · Neptune-like BD+03 2562 b · Gas Giant HD 111591 b · Gas Giant HD 34445 d · Neptune-like MOA-2012-BLG-006L b · Gas Giant HD 76920 b · Gas Giant HD 34445 f · Neptune-like

Host System: HD 40956

Spectral Class

K-type orange

Effective Temperature

4,869 K — cooler than the Sun (5,778 K)

Estimated Age

1.35 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

8.560 R☉

Stellar Mass

2.000 M☉

Metallicity [Fe/H]

0.14

Extended Stellar Properties

Surface gravity (log g)

3.020 dex

Systemic radial velocity

-15.80 km/s

Rotational v·sin i

2.70 km/s

Metallicity ratio

[Fe/H]

Distance

116.59 parsec

Light-years 380.28 ly

V-band magnitude

6.43 mag

Voyager-speed travel 6,706,150 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

8.548 mas

Total Proper Motion

36.542 mas/yr

PM Right Ascension

-35.51 mas/yr

PM Declination

8.62 mas/yr

Galactic Cartesian (pc)

x = -0.013 · y = 0.447 · z = 0.895

Equatorial (J2000)

RA 91.66280° · Dec 63.45388°

Galactic ℓ, b

150.613° · 19.310°

Ecliptic λ, β

90.966° · 40.020°

HTM-20 index

1967992861

Similar Worlds

KMT-2024-BLG-1209L b

Gas Giant · K-type orange

Radius 13.20 R⊕ · 12,817.9 ly

HD 37605 b

Gas Giant · K-type orange

Radius 13.20 R⊕ · 152.6 ly

OGLE-2003-BLG-235L b

Gas Giant · K-type orange

Radius 13.20 R⊕ · 18,917.0 ly

HD 1502 b

Gas Giant · K-type orange

Radius 13.20 R⊕ · 622.8 ly

HD 12661 c

Gas Giant · K-type orange

Radius 13.20 R⊕ · 123.4 ly

HD 181342 b

Gas Giant · K-type orange

Radius 13.20 R⊕ · 392.7 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries Multiple Observatories Mission K-type orange Hosts