Confirmed Exoplanet Discovered 2012

WASP-47 b

A gas giant orbiting the g-type yellow (sun-like) WASP-47, located approximately 863.6 light-years from Earth.

Key parameters at a glance

  • A radius of 12.86 Earth radii
  • A mass of 374.00 Earth masses
  • Surface gravity around 2.26 g
  • An orbital period of 4.159 days
  • Semi-major axis 0.0520 AU
  • Equilibrium temperature 1,275 K (1002 °C)
  • Distance from Earth 863.60 light-years
  • Earth Similarity Index 0.112
  • Travel time at Voyager 1 speed 15,229,512 years

3 siblings around WASP-47

WASP-47 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
WASP-47 e Super-Earth 1.83 9.00 0.790 1,992 2015
WASP-47 b this Gas Giant 12.86 374.00 4.159 1,275 2012
WASP-47 d Sub-Neptune 3.65 15.50 9.031 885 2015
WASP-47 c Unclassified 447.00 589.570 247 2015

WASP-47 b Planet Profile

Physical Specs

Radius
12.86 R⊕
Radius (Jupiter)
1.147 R♃
Mass
374.00 M⊕
Mass (Jupiter)
1.177 M♃
Density
0.99 g/cm³
Surface Gravity
2.26 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.112
HZ Position Inner
Controversial No

Discovery

Year 2012
Method Transit
Facility SuperWASP
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#1054of 1771

top 59.5%

This planet

12.86R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth WASP-47 b Jupiter
Radius (R⊕)1.0012.8611.21
Mass (M⊕)1.00374.00317.83
Density (g/cm³)5.510.991.33
Surface Gravity (g)1.002.262.53
Insolation (S⊕)1.00409.000.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 374.000 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 102264230

Gaia DR2

Gaia DR2 2613413008919918976

Gaia DR3

Gaia DR3 2613413008919918976

System

WASP-47

Percentile among Gas Giant cohort

Radius 12.860 R⊕ · percentile 40 / cohort 1771
Mass 374.000 M⊕ · percentile 40 / cohort 1747
Orbital period 4.16 d · percentile 31 / cohort 1533
Distance 264.78 pc · percentile 57 / cohort 1759
ESI 0.112 · percentile 30 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
4.159 days
Semi-major axis
0.0520 AU
Eccentricity
0.001
Inclination
89.00 °

Year Length

A year here lasts approximately 4.16 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0520 AU.

Transit Fingerprint

Depth

1.271 %

Duration

3.572 h

Impact parameter b

0.173

Rp / R★

0.101930

Transit midpoint (BJD)

2,459,407.7620

Photometric dip

Transit produces a flux drop of 12,712 ppm lasting ≈ 3.57 h.

Extended Orbital Architecture

Planet / star radius ratio

0.101930

Semi-major axis / stellar radius

9.700

Impact parameter (b)

0.173

RV semi-amplitude (K)

140.840 m/s

Transit mid-time (BJD)

2,459,407.7620

Long. of periastron (ω)

89.00°

Sky-projected obliquity (λ)

0.00°

True obliquity (ψ)

29.20°

Angular separation (arcsec)

0.19600

Eq. Temperature

1,275K

(1002 °C)

Insolation (S⊕)

409.00

Earth = 1.00

Earth Similarity (ESI)

0.112

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Hellier et al. 2012

Instrument

iKon-L CCD Camera

Publication

2012-10

Observation locale

Ground

Host System: WASP-47

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,565 K — cooler than the Sun (5,778 K)

Estimated Age

6.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.156 R☉

Stellar Mass

1.058 M☉

Metallicity [Fe/H]

0.43

Extended Stellar Properties

Surface gravity (log g)

4.344 dex

Stellar density

0.998 g/cm³

Systemic radial velocity

-27.06 km/s

Rotational v·sin i

1.80 km/s

Rotation period

39.40 days

Activity index (log R'HK)

-5.201

Metallicity ratio

[Fe/H]

Distance
264.78 parsec
Light-years 863.60 ly
V-band magnitude
11.94 mag
Voyager-speed travel 15,229,512 yr

Multi-band Host Photometry — 12 bands

8.712.712.74B11.94V11.79Gaia11.76Kepler11.29TESS10.61J10.31H10.19K10.17W110.24W210.17W38.75W4

Astrometric Data

Parallax

3.750 mas

Total Proper Motion

43.956 mas/yr

PM Right Ascension

15.02 mas/yr

PM Declination

-41.31 mas/yr

Galactic Cartesian (pc)

x = 0.857 · y = -0.471 · z = -0.208

Equatorial (J2000)

RA 331.20309° · Dec -12.01907°

Galactic ℓ, b

45.748° · -48.187°

Ecliptic λ, β

328.992° · -0.209°

HTM-20 index

-1742555658

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