Confirmed Exoplanet Discovered 2009

WASP-15 b

A gas giant orbiting the f-type yellow-white WASP-15, located approximately 920.1 light-years from Earth.

Key parameters at a glance

  • A radius of 15.80 Earth radii
  • A mass of 171.63 Earth masses
  • Surface gravity around 0.69 g
  • An orbital period of 3.752 days
  • Semi-major axis 0.0517 AU
  • Equilibrium temperature 1,676 K (1403 °C)
  • Distance from Earth 920.06 light-years
  • Earth Similarity Index 0.061
  • Travel time at Voyager 1 speed 16,225,199 years

WASP-15 b Planet Profile

Physical Specs

Radius
15.80 R⊕
Radius (Jupiter)
1.410 R♃
Mass
171.63 M⊕
Mass (Jupiter)
0.540 M♃
Density
0.26 g/cm³
Surface Gravity
0.69 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.061
HZ Position Inner
Controversial No

Discovery

Year 2009
Method Transit
Facility SuperWASP
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#174of 1771

top 9.8%

This planet

15.80R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth WASP-15 b Jupiter
Radius (R⊕)1.0015.8011.21
Mass (M⊕)1.00171.63317.83
Density (g/cm³)5.510.261.33
Surface Gravity (g)1.000.692.53
Insolation (S⊕)1.001,237.740.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 171.628 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 111991770

Gaia DR2

Gaia DR2 6171009049549197824

Gaia DR3

Gaia DR3 6171009049549197824

System

WASP-15

Percentile among Gas Giant cohort

Radius 15.805 R⊕ · percentile 90 / cohort 1771
Mass 171.628 M⊕ · percentile 15 / cohort 1747
Orbital period 3.75 d · percentile 26 / cohort 1533
Distance 282.09 pc · percentile 58 / cohort 1759
ESI 0.061 · percentile 9 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
3.752 days
Semi-major axis
0.0517 AU
Eccentricity
0.000
Inclination
85.96 °

Year Length

A year here lasts approximately 3.75 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0517 AU.

Transit Fingerprint

Depth

0.970 %

Duration

3.713 h

Impact parameter b

0.525

Rp / R★

0.098420

Transit midpoint (BJD)

2,456,036.7605

Photometric dip

Transit produces a flux drop of 9,700 ppm lasting ≈ 3.71 h.

Extended Orbital Architecture

Planet / star radius ratio

0.098420

Semi-major axis / stellar radius

7.290

Impact parameter (b)

0.525

RV semi-amplitude (K)

63.400 m/s

Transit mid-time (BJD)

2,456,036.7605

Long. of periastron (ω)

240.00°

Sky-projected obliquity (λ)

-139.60°

Angular separation (arcsec)

0.18300

Eq. Temperature

1,676K

(1403 °C)

Insolation (S⊕)

1,237.74

Earth = 1.00

Earth Similarity (ESI)

0.061

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

West et al. 2009

Instrument

iKon-L CCD Camera

Publication

2009-06

Observation locale

Ground

Host System: WASP-15

Spectral Class

F-type yellow-white

Effective Temperature

6,300 K — hotter than the Sun (5,778 K)

Estimated Age

2.40 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.480 R☉

Stellar Mass

1.180 M☉

Metallicity [Fe/H]

-0.17

Extended Stellar Properties

Surface gravity (log g)

4.350 dex

Stellar density

0.520 g/cm³

Systemic radial velocity

-2.34 km/s

Rotational v·sin i

4.27 km/s

Metallicity ratio

[Fe/H]

Distance
282.09 parsec
Light-years 920.06 ly
V-band magnitude
10.97 mag
Voyager-speed travel 16,225,199 yr

Multi-band Host Photometry — 11 bands

8.511.311.34B10.97V10.80Gaia10.44TESS9.96J9.71H9.69K9.65W19.67W29.63W38.45W4

Astrometric Data

Parallax

3.517 mas

Total Proper Motion

24.047 mas/yr

PM Right Ascension

8.77 mas/yr

PM Declination

-22.39 mas/yr

Galactic Cartesian (pc)

x = -0.741 · y = -0.409 · z = -0.532

Equatorial (J2000)

RA 208.92801° · Dec -32.15971°

Galactic ℓ, b

318.437° · 28.770°

Ecliptic λ, β

218.404° · -18.994°

HTM-20 index

1095737268

Observation Record

Photometric series

2

RV measurements

1

Transmission spectra

4

Emission spectra

1

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