Confirmed Exoplanet Discovered 2019

WASP-171 b

A gas giant orbiting the g-type yellow (sun-like) WASP-171, located approximately 2,471.7 light-years from Earth.

Key parameters at a glance

  • A radius of 10.98 Earth radii
  • A mass of 344.53 Earth masses
  • Surface gravity around 2.86 g
  • An orbital period of 3.819 days
  • Semi-major axis 0.0504 AU
  • Equilibrium temperature 1,642 K (1369 °C)
  • Distance from Earth 2,471.74 light-years
  • Earth Similarity Index 0.093
  • Travel time at Voyager 1 speed 43,589,144 years

WASP-171 b Planet Profile

Physical Specs

Radius
10.98 R⊕
Radius (Jupiter)
0.980 R♃
Mass
344.53 M⊕
Mass (Jupiter)
1.084 M♃
Density
1.50 g/cm³
Surface Gravity
2.86 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.093
HZ Position Inner
Controversial No

Discovery

Year 2019
Method Transit
Facility WASP-South
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#1665of 1771

top 94.0%

This planet

10.98R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth WASP-171 b Jupiter
Radius (R⊕)1.0010.9811.21
Mass (M⊕)1.00344.53317.83
Density (g/cm³)5.511.501.33
Surface Gravity (g)1.002.862.53
Insolation (S⊕)1.001,200.240.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 344.528 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 162922904

Gaia DR2

Gaia DR2 5376137837173646208

Gaia DR3

Gaia DR3 5376137837173646208

System

WASP-171

Percentile among Gas Giant cohort

Radius 10.985 R⊕ · percentile 6 / cohort 1771
Mass 344.528 M⊕ · percentile 37 / cohort 1747
Orbital period 3.82 d · percentile 27 / cohort 1533
Distance 757.84 pc · percentile 82 / cohort 1759
ESI 0.093 · percentile 24 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
3.819 days
Semi-major axis
0.0504 AU
Eccentricity
0.000
Inclination
88.30 °

Year Length

A year here lasts approximately 3.82 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0504 AU.

Transit Fingerprint

Depth

0.382 %

Duration

4.579 h

Impact parameter b

0.190

Transit midpoint (BJD)

2,458,059.8295

Photometric dip

Transit produces a flux drop of 3,820 ppm lasting ≈ 4.58 h.

Extended Orbital Architecture

Semi-major axis / stellar radius

6.640

Impact parameter (b)

0.190

RV semi-amplitude (K)

126.000 m/s

Transit mid-time (BJD)

2,458,059.8295

Angular separation (arcsec)

0.06650

Eq. Temperature

1,642K

(1369 °C)

Insolation (S⊕)

1,200.24

Earth = 1.00

Earth Similarity (ESI)

0.093

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

Nielsen et al. 2019

Instrument

iKon-L CCD Camera

Publication

2019-10

Observation locale

Ground

Host System: WASP-171

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,965 K — hotter than the Sun (5,778 K)

Estimated Age

5.91 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.637 R☉

Stellar Mass

1.171 M☉

Metallicity [Fe/H]

0.04

Extended Stellar Properties

Surface gravity (log g)

4.080 dex

Stellar density

0.381 g/cm³

Systemic radial velocity

10.48 km/s

Rotational v·sin i

6.30 km/s

Metallicity ratio

[Fe/H]

Distance
757.84 parsec
Light-years 2,471.74 ly
V-band magnitude
12.61 mag
Voyager-speed travel 43,589,144 yr

Multi-band Host Photometry — 11 bands

8.913.213.18B12.61V12.44Gaia12.02TESS11.42J11.16H11.10K11.06W111.10W211.01W38.93W4

Astrometric Data

Parallax

1.291 mas

Total Proper Motion

8.725 mas/yr

PM Right Ascension

-8.43 mas/yr

PM Declination

-2.26 mas/yr

Galactic Cartesian (pc)

x = -0.711 · y = 0.102 · z = -0.696

Equatorial (J2000)

RA 171.84505° · Dec -44.08870°

Galactic ℓ, b

287.371° · 16.229°

Ecliptic λ, β

194.451° · -42.757°

HTM-20 index

1393834002

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