Key parameters at a glance

A radius of 11.43 Earth radii
A mass of 772.33 Earth masses
Surface gravity around 5.91 g
An orbital period of 5.753 days
Semi-major axis 0.0717 AU
Equilibrium temperature 1,480 K (1207 °C)
Distance from Earth 517.48 light-years
Earth Similarity Index 0.111
Travel time at Voyager 1 speed 9,125,744 years

WASP-99 b Planet Profile

Physical Specs

Radius

11.43 R⊕

Radius (Jupiter)

1.020 R♃

Mass

772.33 M⊕

Mass (Jupiter)

2.430 M♃

Density

2.79 g/cm³

Surface Gravity

5.91 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.111

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit

Facility SuperWASP

Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#1596of 1771

top 90.1%

This planet

11.43R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

TOI-564 b 11.43 R⊕ TOI-7041 b 11.43 R⊕ HATS-4 b 11.43 R⊕

Metric	Earth	WASP-99 b	Jupiter
Radius (R⊕)	1.00	11.43	11.21
Mass (M⊕)	1.00	772.33	317.83
Density (g/cm³)	5.51	2.79	1.33
Surface Gravity (g)	1.00	5.91	2.53
Insolation (S⊕)	1.00	828.83	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	772.327 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 166836920

Gaia DR2

Gaia DR2 4745660479479743488

Gaia DR3

Gaia DR3 4745660479479743488

System

WASP-99

Percentile among Gas Giant cohort

Radius 11.433 R⊕ · percentile 10 / cohort 1771

Mass 772.327 M⊕ · percentile 60 / cohort 1747

Orbital period 5.75 d · percentile 39 / cohort 1533

Distance 158.66 pc · percentile 45 / cohort 1759

ESI 0.111 · percentile 29 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

5.753 days

Semi-major axis

0.0717 AU

Eccentricity

0.000

Inclination

88.80 °

Year Length

A year here lasts approximately 5.75 Earth days (1.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0717 AU.

Transit Fingerprint

Depth

0.410 %

Duration

5.407 h

Impact parameter b

0.100

Rp / R★

0.067800

Transit midpoint (BJD)

2,459,135.7959

Photometric dip

Transit produces a flux drop of 4,100 ppm lasting ≈ 5.41 h.

Extended Orbital Architecture

Planet / star radius ratio

0.067800

Semi-major axis / stellar radius

8.770

Impact parameter (b)

0.100

RV semi-amplitude (K)

242.200 m/s

Transit mid-time (BJD)

2,459,135.7959

Angular separation (arcsec)

0.45200

Eq. Temperature

1,480K

(1207 °C)

Insolation (S⊕)

828.83

Earth = 1.00

Earth Similarity (ESI)

0.111

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

Hellier et al. 2014

Instrument

iKon-L CCD Camera

Publication

2014-05

Observation locale

Ground

Discovery cohort

Planets confirmed in 2014 at SuperWASP (12 shown).

WASP-94 B b · Gas Giant WASP-84 b · Gas Giant WASP-106 b · Gas Giant WASP-117 b · Gas Giant WASP-69 b · Gas Giant WASP-98 b · Gas Giant WASP-104 b · Gas Giant WASP-96 b · Gas Giant WASP-97 b · Gas Giant WASP-70 A b · Gas Giant WASP-28 b · Gas Giant WASP-68 b · Gas Giant

Host System: WASP-99

Spectral Class

F-type yellow-white

Effective Temperature

6,150 K — hotter than the Sun (5,778 K)

Estimated Age

3.00 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.640 R☉

Stellar Mass

1.210 M☉

Metallicity [Fe/H]

0.21

Extended Stellar Properties

Surface gravity (log g)

4.300 dex

Stellar density

0.390 g/cm³

Systemic radial velocity

24.96 km/s

Rotational v·sin i

6.80 km/s

Metallicity ratio

[Fe/H]

Distance

158.66 parsec

Light-years 517.48 ly

V-band magnitude

9.48 mag

Voyager-speed travel 9,125,744 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

6.274 mas

Total Proper Motion

39.900 mas/yr

PM Right Ascension

-1.87 mas/yr

PM Declination

-39.86 mas/yr

Galactic Cartesian (pc)

x = 0.493 · y = 0.412 · z = -0.766

Equatorial (J2000)

RA 39.89767° · Dec -50.00819°

Galactic ℓ, b

268.163° · -59.183°

Ecliptic λ, β

8.470° · -60.099°

HTM-20 index

1730462083