Key parameters at a glance

A radius of 13.45 Earth radii
A mass of 276.83 Earth masses
Surface gravity around 1.53 g
An orbital period of 3.110 days
Semi-major axis 0.0430 AU
Equilibrium temperature 1,468 K (1195 °C)
Distance from Earth 1,303.42 light-years
Earth Similarity Index 0.087
Travel time at Voyager 1 speed 22,985,761 years

WASP-155 b Planet Profile

Physical Specs

Radius

13.45 R⊕

Radius (Jupiter)

1.200 R♃

Mass

276.83 M⊕

Mass (Jupiter)

0.871 M♃

Density

0.62 g/cm³

Surface Gravity

1.53 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.087

HZ Position Inner

Controversial No

Discovery

Year 2025

Method Transit

Facility SuperWASP

Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#724of 1771

top 40.8%

This planet

13.45R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

K2-97 b 13.45 R⊕ WASP-173 A b 13.45 R⊕ WASP-96 b 13.45 R⊕

Metric	Earth	WASP-155 b	Jupiter
Radius (R⊕)	1.00	13.45	11.21
Mass (M⊕)	1.00	276.83	317.83
Density (g/cm³)	5.51	0.62	1.33
Surface Gravity (g)	1.00	1.53	2.53
Insolation (S⊕)	1.00	771.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	276.829 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 100909102

System

WASP-155

Percentile among Gas Giant cohort

Radius 13.451 R⊕ · percentile 59 / cohort 1771

Mass 276.829 M⊕ · percentile 30 / cohort 1747

Orbital period 3.11 d · percentile 17 / cohort 1533

Distance 399.63 pc · percentile 70 / cohort 1759

ESI 0.087 · percentile 21 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

3.110 days

Semi-major axis

0.0430 AU

Eccentricity

0.000

Inclination

86.70 °

Year Length

A year here lasts approximately 3.11 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0430 AU.

Transit Fingerprint

Depth

0.994 %

Duration

3.129 h

Impact parameter b

0.430

Rp / R★

0.099700

Transit midpoint (BJD)

2,459,852.0849

Photometric dip

Transit produces a flux drop of 9,940 ppm lasting ≈ 3.13 h.

Extended Orbital Architecture

Planet / star radius ratio

0.099700

Semi-major axis / stellar radius

7.430

Impact parameter (b)

0.430

RV semi-amplitude (K)

114.290 m/s

Transit mid-time (BJD)

2,459,852.0849

Angular separation (arcsec)

0.10800

Eq. Temperature

1,468K

(1195 °C)

Insolation (S⊕)

771.00

Earth = 1.00

Earth Similarity (ESI)

0.087

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Schanche et al. 2025

Instrument

e2v CCD Camera

Publication

2025-04

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at SuperWASP (8 shown).

WASP-154 b · Gas Giant WASP-116 b · Gas Giant WASP-188 b · Gas Giant WASP-197 b · Gas Giant WASP-194 b · Gas Giant WASP-195 b · Gas Giant WASP-102 b · Gas Giant WASP-149 b · Gas Giant

Host System: WASP-155

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,660 K — cooler than the Sun (5,778 K)

Estimated Age

1.70 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.240 R☉

Stellar Mass

1.090 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.300 dex

Stellar density

0.803 g/cm³

Metallicity ratio

[Fe/H]

Distance

399.63 parsec

Light-years 1,303.42 ly

V-band magnitude

12.37 mag

Voyager-speed travel 22,985,761 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

2.474 mas

Total Proper Motion

33.792 mas/yr

PM Right Ascension

18.71 mas/yr

PM Declination

-28.14 mas/yr

Galactic Cartesian (pc)

x = 0.820 · y = -0.175 · z = 0.545

Equatorial (J2000)

RA 347.97972° · Dec 33.04761°

Galactic ℓ, b

99.964° · -25.347°

Ecliptic λ, β

3.957° · 34.734°

HTM-20 index

-53019520