Key parameters at a glance

A radius of 12.33 Earth radii
A mass of 238.69 Earth masses
Surface gravity around 1.57 g
An orbital period of 3.276 days
Semi-major axis 0.0441 AU
Equilibrium temperature 1,146 K (873 °C)
Distance from Earth 2,565.17 light-years
Earth Similarity Index 0.122
Travel time at Voyager 1 speed 45,236,735 years

NGTS-15 b Planet Profile

Physical Specs

Radius

12.33 R⊕

Radius (Jupiter)

1.100 R♃

Mass

238.69 M⊕

Mass (Jupiter)

0.751 M♃

Density

0.74 g/cm³

Surface Gravity

1.57 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.122

HZ Position Inner

Controversial No

Discovery

Year 2021

Method Transit

Facility Next-Generation Transit Survey (NGTS)

Telescope 20 cm NGTS telescope

Size rank in cohort

Rank by radius

#1345of 1771

top 75.9%

This planet

12.33R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

TOI-2969 b 12.33 R⊕ WASP-44 b 12.33 R⊕ WASP-41 b 12.33 R⊕

Metric	Earth	NGTS-15 b	Jupiter
Radius (R⊕)	1.00	12.33	11.21
Mass (M⊕)	1.00	238.69	317.83
Density (g/cm³)	5.51	0.74	1.33
Surface Gravity (g)	1.00	1.57	2.53
Insolation (S⊕)	1.00	425.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	238.689 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 1333933

Gaia DR2

Gaia DR2 4873830691665395584

Gaia DR3

Gaia DR3 4873830691665395584

System

NGTS-15

Percentile among Gas Giant cohort

Radius 12.330 R⊕ · percentile 24 / cohort 1771

Mass 238.689 M⊕ · percentile 26 / cohort 1747

Orbital period 3.28 d · percentile 19 / cohort 1533

Distance 786.49 pc · percentile 83 / cohort 1759

ESI 0.122 · percentile 32 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

3.276 days

Semi-major axis

0.0441 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 3.28 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0441 AU.

Transit Fingerprint

Duration

2.504 h

Impact parameter b

0.509

Rp / R★

0.119000

Transit midpoint (BJD)

2,458,405.0558

Extended Orbital Architecture

Planet / star radius ratio

0.119000

Semi-major axis / stellar radius

10.000

Impact parameter (b)

0.509

RV semi-amplitude (K)

106.000 m/s

Transit mid-time (BJD)

2,458,405.0558

Angular separation (arcsec)

0.05610

Eq. Temperature

1,146K

(873 °C)

Insolation (S⊕)

425.00

Earth = 1.00

Earth Similarity (ESI)

0.122

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

Tilbrook et al. 2021

Instrument

NGTS CCD array

Publication

2021-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2021 at Next-Generation Transit Survey (NGTS) (5 shown).

NGTS-14 A b · Neptune-like NGTS-13 b · Gas Giant NGTS-16 b · Gas Giant NGTS-17 b · Gas Giant NGTS-18 b · Gas Giant

Host System: NGTS-15

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,600 K — cooler than the Sun (5,778 K)

Estimated Age

3.28 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.954 R☉

Stellar Mass

0.995 M☉

Metallicity [Fe/H]

0.15

Extended Stellar Properties

Surface gravity (log g)

4.400 dex

Stellar density

1.615 g/cm³

Systemic radial velocity

34.68 km/s

Rotational v·sin i

2.00 km/s

Metallicity ratio

[Fe/H]

Distance

786.49 parsec

Light-years 2,565.17 ly

V-band magnitude

14.67 mag

Voyager-speed travel 45,236,735 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

1.243 mas

Total Proper Motion

5.837 mas/yr

PM Right Ascension

5.69 mas/yr

PM Declination

1.32 mas/yr

Galactic Cartesian (pc)

x = 0.241 · y = 0.805 · z = -0.542

Equatorial (J2000)

RA 73.35531° · Dec -32.80035°

Galactic ℓ, b

234.783° · -37.984°

Ecliptic λ, β

65.294° · -54.821°

HTM-20 index

736925770