Confirmed Exoplanet Discovered 2008

WASP-7 b

A gas giant orbiting the f-type yellow-white WASP-7, located approximately 529.4 light-years from Earth.

Key parameters at a glance

  • A radius of 14.91 Earth radii
  • A mass of 305.12 Earth masses
  • Surface gravity around 1.37 g
  • An orbital period of 4.955 days
  • Semi-major axis 0.0617 AU
  • Equilibrium temperature 1,487 K (1214 °C)
  • Distance from Earth 529.36 light-years
  • Earth Similarity Index 0.082
  • Travel time at Voyager 1 speed 9,335,280 years

WASP-7 b Planet Profile

Physical Specs

Radius
14.91 R⊕
Radius (Jupiter)
1.330 R♃
Mass
305.12 M⊕
Mass (Jupiter)
0.960 M♃
Density
0.55 g/cm³
Surface Gravity
1.37 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.082
HZ Position Inner
Controversial No

Discovery

Year 2008
Method Transit
Facility SuperWASP
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#237of 1771

top 13.3%

This planet

14.91R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth WASP-7 b Jupiter
Radius (R⊕)1.0014.9111.21
Mass (M⊕)1.00305.12317.83
Density (g/cm³)5.510.551.33
Surface Gravity (g)1.001.372.53
Insolation (S⊕)1.00612.690.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 305.117 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

HD

HD 197286

TIC

TIC 389352124

Gaia DR2

Gaia DR2 6681720724498802176

Gaia DR3

Gaia DR3 6681720724498802176

System

WASP-7

Percentile among Gas Giant cohort

Radius 14.908 R⊕ · percentile 86 / cohort 1771
Mass 305.117 M⊕ · percentile 34 / cohort 1747
Orbital period 4.95 d · percentile 36 / cohort 1533
Distance 162.30 pc · percentile 46 / cohort 1759
ESI 0.082 · percentile 19 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
4.955 days
Semi-major axis
0.0617 AU
Eccentricity
0.034
Inclination
87.03 °

Year Length

A year here lasts approximately 4.95 Earth days (1.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0617 AU.

Transit Fingerprint

Depth

0.736 %

Duration

3.639 h

Impact parameter b

0.530

Rp / R★

0.095600

Transit midpoint (BJD)

2,455,446.6349

Photometric dip

Transit produces a flux drop of 7,357 ppm lasting ≈ 3.64 h.

Extended Orbital Architecture

Planet / star radius ratio

0.095600

Semi-major axis / stellar radius

9.074

Impact parameter (b)

0.530

RV semi-amplitude (K)

97.000 m/s

Transit mid-time (BJD)

2,455,446.6349

Long. of periastron (ω)

109.00°

Sky-projected obliquity (λ)

86.00°

Angular separation (arcsec)

0.38000

Eq. Temperature

1,487K

(1214 °C)

Insolation (S⊕)

612.69

Earth = 1.00

Earth Similarity (ESI)

0.082

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. 2008

Instrument

iKon-L CCD Camera

Publication

2009-01

Observation locale

Ground

Host System: WASP-7

Spectral Class

F-type yellow-white

Effective Temperature

6,400 K — hotter than the Sun (5,778 K)

Estimated Age

2.40 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.432 R☉

Stellar Mass

1.276 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.232 dex

Stellar density

0.611 g/cm³

Systemic radial velocity

-29.85 km/s

Rotational v·sin i

17.00 km/s

Metallicity ratio

[Fe/H]

Distance
162.30 parsec
Light-years 529.36 ly
V-band magnitude
9.50 mag
Voyager-speed travel 9,335,280 yr

Multi-band Host Photometry — 11 bands

8.210.09.98B9.50V9.38Gaia9.05TESS8.65J8.41H8.40K8.36W18.38W28.36W38.21W4

Astrometric Data

Parallax

6.133 mas

Total Proper Motion

64.945 mas/yr

PM Right Ascension

30.47 mas/yr

PM Declination

-57.36 mas/yr

Galactic Cartesian (pc)

x = 0.509 · y = -0.584 · z = -0.632

Equatorial (J2000)

RA 311.04276° · Dec -39.22549°

Galactic ℓ, b

2.822° · -37.877°

Ecliptic λ, β

302.852° · -20.352°

HTM-20 index

1788317856

Observation Record

Photometric series

1

RV measurements

1

Emission spectra

2

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