Key parameters at a glance

A radius of 14.45 Earth radii
A mass of 403.32 Earth masses
Surface gravity around 1.93 g
An orbital period of 5.167 days
Semi-major axis 0.0650 AU
Equilibrium temperature 1,665 K (1392 °C)
Distance from Earth 1,577.54 light-years
Earth Similarity Index 0.076
Travel time at Voyager 1 speed 27,819,829 years

WASP-197 b Planet Profile

Physical Specs

Radius

14.45 R⊕

Radius (Jupiter)

1.289 R♃

Mass

403.32 M⊕

Mass (Jupiter)

1.269 M♃

Density

0.74 g/cm³

Surface Gravity

1.93 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.076

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

#286of 1771

top 16.1%

This planet

14.45R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HAT-P-50 b 14.44 R⊕ TOI-3980 b 14.46 R⊕ TOI-2583 A b 14.46 R⊕

Metric	Earth	WASP-197 b	Jupiter
Radius (R⊕)	1.00	14.45	11.21
Mass (M⊕)	1.00	403.32	317.83
Density (g/cm³)	5.51	0.74	1.33
Surface Gravity (g)	1.00	1.93	2.53
Insolation (S⊕)	1.00	1,276.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	403.324 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 85266608

Gaia DR2

Gaia DR2 734156218947945216

Gaia DR3

Gaia DR3 734156218947945216

System

WASP-197

Percentile among Gas Giant cohort

Radius 14.448 R⊕ · percentile 84 / cohort 1771

Mass 403.324 M⊕ · percentile 42 / cohort 1747

Orbital period 5.17 d · percentile 37 / cohort 1533

Distance 483.68 pc · percentile 74 / cohort 1759

ESI 0.076 · percentile 16 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

5.167 days

Semi-major axis

0.0650 AU

Eccentricity

0.000

Inclination

86.29 °

Year Length

A year here lasts approximately 5.17 Earth days (1.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0650 AU.

Transit Fingerprint

Depth

0.393 %

Duration

5.976 h

Impact parameter b

0.430

Rp / R★

0.062700

Transit midpoint (BJD)

2,456,885.1043

Photometric dip

Transit produces a flux drop of 3,931 ppm lasting ≈ 5.98 h.

Extended Orbital Architecture

Planet / star radius ratio

0.062700

Semi-major axis / stellar radius

6.600

Impact parameter (b)

0.430

RV semi-amplitude (K)

121.320 m/s

Transit mid-time (BJD)

2,456,885.1043

Angular separation (arcsec)

0.13400

Eq. Temperature

1,665K

(1392 °C)

Insolation (S⊕)

1,276.00

Earth = 1.00

Earth Similarity (ESI)

0.076

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-155 b · Gas Giant WASP-116 b · Gas Giant WASP-188 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-197

Spectral Class

F-type yellow-white

Effective Temperature

6,050 K — hotter than the Sun (5,778 K)

Estimated Age

2.60 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.112 R☉

Stellar Mass

1.360 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

3.900 dex

Stellar density

0.204 g/cm³

Metallicity ratio

[Fe/H]

Distance

483.68 parsec

Light-years 1,577.54 ly

V-band magnitude

11.57 mag

Voyager-speed travel 27,819,829 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

2.039 mas

Total Proper Motion

9.221 mas/yr

PM Right Ascension

-9.18 mas/yr

PM Declination

0.85 mas/yr

Galactic Cartesian (pc)

x = -0.831 · y = 0.292 · z = 0.473

Equatorial (J2000)

RA 160.63071° · Dec 28.19863°

Galactic ℓ, b

203.201° · 61.519°

Ecliptic λ, β

151.246° · 18.498°

HTM-20 index

1422312689