Confirmed Exoplanet Discovered 2018

WASP-147 b

A gas giant orbiting the g-type yellow (sun-like) WASP-147, located approximately 1,422.4 light-years from Earth.

Key parameters at a glance

  • A radius of 12.50 Earth radii
  • A mass of 87.40 Earth masses
  • Surface gravity around 0.56 g
  • An orbital period of 4.603 days
  • Semi-major axis 0.0549 AU
  • Equilibrium temperature 1,404 K (1131 °C)
  • Distance from Earth 1,422.36 light-years
  • Earth Similarity Index 0.080
  • Travel time at Voyager 1 speed 25,083,314 years

WASP-147 b Planet Profile

Physical Specs

Radius
12.50 R⊕
Radius (Jupiter)
1.115 R♃
Mass
87.40 M⊕
Mass (Jupiter)
0.275 M♃
Density
0.26 g/cm³
Surface Gravity
0.56 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.080
HZ Position Inner
Controversial No

Discovery

Year 2018
Method Transit
Facility SuperWASP-South
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#1282of 1771

top 72.3%

This planet

12.50R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth WASP-147 b Jupiter
Radius (R⊕)1.0012.5011.21
Mass (M⊕)1.0087.40317.83
Density (g/cm³)5.510.261.33
Surface Gravity (g)1.000.562.53
Insolation (S⊕)1.00639.490.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 87.403 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 114749636

Gaia DR2

Gaia DR2 2340919358581488768

Gaia DR3

Gaia DR3 2340919358581488768

System

WASP-147

Percentile among Gas Giant cohort

Radius 12.498 R⊕ · percentile 28 / cohort 1771
Mass 87.403 M⊕ · percentile 4 / cohort 1747
Orbital period 4.60 d · percentile 34 / cohort 1533
Distance 436.10 pc · percentile 72 / cohort 1759
ESI 0.080 · percentile 18 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
4.603 days
Semi-major axis
0.0549 AU
Eccentricity
0.000
Inclination
87.90 °

Year Length

A year here lasts approximately 4.60 Earth days (1.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0549 AU.

Transit Fingerprint

Depth

0.640 %

Duration

4.394 h

Impact parameter b

0.310

Rp / R★

0.080000

Transit midpoint (BJD)

2,456,562.5950

Photometric dip

Transit produces a flux drop of 6,400 ppm lasting ≈ 4.39 h.

Extended Orbital Architecture

Planet / star radius ratio

0.080000

Semi-major axis / stellar radius

8.290

Impact parameter (b)

0.310

RV semi-amplitude (K)

32.700 m/s

Transit mid-time (BJD)

2,456,562.5950

Angular separation (arcsec)

0.12600

Eq. Temperature

1,404K

(1131 °C)

Insolation (S⊕)

639.49

Earth = 1.00

Earth Similarity (ESI)

0.080

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

Lendl et al. 2019

Instrument

iKon-L CCD Camera

Publication

2019-01

Observation locale

Ground

Host System: WASP-147

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,702 K — cooler than the Sun (5,778 K)

Estimated Age

8.47 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.429 R☉

Stellar Mass

1.044 M☉

Metallicity [Fe/H]

0.09

Extended Stellar Properties

Surface gravity (log g)

4.210 dex

Stellar density

0.509 g/cm³

Systemic radial velocity

-1.62 km/s

Rotational v·sin i

0.30 km/s

Metallicity ratio

[Fe/H]

Distance
436.10 parsec
Light-years 1,422.36 ly
V-band magnitude
12.68 mag
Voyager-speed travel 25,083,314 yr

Multi-band Host Photometry — 11 bands

9.013.113.11B12.68V12.18Gaia11.76TESS11.17J10.91H10.86K10.79W110.84W210.80W39.00W4

Astrometric Data

Parallax

2.265 mas

Total Proper Motion

8.748 mas/yr

PM Right Ascension

-5.29 mas/yr

PM Declination

-6.96 mas/yr

Galactic Cartesian (pc)

x = 0.926 · y = -0.013 · z = -0.377

Equatorial (J2000)

RA 359.19151° · Dec -22.15323°

Galactic ℓ, b

51.793° · -76.628°

Ecliptic λ, β

350.075° · -19.924°

HTM-20 index

243735814

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