Key parameters at a glance

A radius of 15.69 Earth radii
A mass of 1,938.75 Earth masses
Surface gravity around 7.87 g
An orbital period of 117,000.000 days
Semi-major axis 63.0000 AU
Equilibrium temperature 1,042 K (769 °C)
Distance from Earth 445.56 light-years
Earth Similarity Index 0.151
Travel time at Voyager 1 speed 7,857,365 years

brightness_6

Circumbinary planet

HD 143811 AB b orbits a binary-star pair rather than a single host — a minority architecture in the confirmed catalogue.

HD 143811 AB b Planet Profile

Physical Specs

Radius

15.69 R⊕

Radius (Jupiter)

1.400 R♃

Mass

1,938.75 M⊕

Mass (Jupiter)

6.100 M♃

Density

2.76 g/cm³

Surface Gravity

7.87 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.151

HZ Position Unknown

Controversial No

Discovery

Year 2025

Method Imaging

Facility Paranal Observatory

Telescope 8.2 m ESO VLT UT3 Melipal Telescope

Size rank in cohort

Rank by radius

#184of 1771

top 10.3%

This planet

15.69R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

TOI-1295 b 15.69 R⊕ 2MASS J12073346-3932539 b 15.69 R⊕ WASP-66 b 15.69 R⊕

Metric	Earth	HD 143811 AB b	Jupiter
Radius (R⊕)	1.00	15.69	11.21
Mass (M⊕)	1.00	1,938.75	317.83
Density (g/cm³)	5.51	2.76	1.33
Surface Gravity (g)	1.00	7.87	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1,938.753 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 143811 A

HIP

HIP 78663

TIC

TIC 93869857

Gaia DR2

Gaia DR2 6040105283968486144

Gaia DR3

Gaia DR3 6040105283968486144

System

HD 143811

Percentile among Gas Giant cohort

Radius 15.693 R⊕ · percentile 89 / cohort 1771

Mass 1,938.753 M⊕ · percentile 79 / cohort 1747

Orbital period 117,000.00 d · percentile 100 / cohort 1533

Distance 136.61 pc · percentile 42 / cohort 1759

ESI 0.151 · percentile 36 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

117,000.000 days

Semi-major axis

63.0000 AU

Eccentricity

0.190

Inclination

37.00 °

Year Length

A year here lasts about 320.33 Earth years on a mildly elliptical path at a mean orbital distance of 63.0000 AU.

Eq. Temperature

1,042K

(769 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.151

0 = alien, 1 = Earth-identical

Insufficient insolation data — the dayside is scorched.

Discovery Paper

Primary reference

Squicciarini et al. 2025

Instrument

SPHERE

Publication

2025-09

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at Paranal Observatory (8 shown).

TOI-771 c · Super-Earth HD 35843 b · Sub-Neptune WISPIT 1 c · Gas Giant K2-157 d · Neptune-like WISPIT 1 b · Gas Giant WISPIT 2 b · Gas Giant K2-157 c · Neptune-like HD 135344 A b · Gas Giant

Host System: HD 143811 A

Spectral Class

F-type yellow-white

Effective Temperature

6,791 K — hotter than the Sun (5,778 K)

Estimated Age

0.02 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.684 R☉

Stellar Mass

1.320 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

4.340 dex

Stellar density

0.384 g/cm³

Rotational v·sin i

7.50 km/s

Distance

136.61 parsec

Light-years 445.56 ly

V-band magnitude

8.91 mag

Voyager-speed travel 7,857,365 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

7.292 mas

Total Proper Motion

29.209 mas/yr

PM Right Ascension

-15.09 mas/yr

PM Declination

-25.01 mas/yr

Galactic Cartesian (pc)

x = -0.421 · y = -0.756 · z = -0.502

Equatorial (J2000)

RA 240.88920° · Dec -30.13716°

Galactic ℓ, b

345.074° · 16.606°

Ecliptic λ, β

244.767° · -9.212°

HTM-20 index

-2077098837