Confirmed Exoplanet Discovered 2017

NGTS-1 b

A gas giant orbiting the m-type red dwarf NGTS-1, located approximately 711.4 light-years from Earth.

Key parameters at a glance

  • A radius of 14.91 Earth radii
  • A mass of 258.08 Earth masses
  • Surface gravity around 1.16 g
  • An orbital period of 2.647 days
  • Semi-major axis 0.0326 AU
  • Equilibrium temperature 790 K (517 °C)
  • Distance from Earth 711.41 light-years
  • Earth Similarity Index 0.156
  • Travel time at Voyager 1 speed 12,545,798 years
  • Almost certainly tidally locked to its host star given the close orbit

NGTS-1 b Planet Profile

Physical Specs

Radius
14.91 R⊕
Radius (Jupiter)
1.330 R♃
Mass
258.08 M⊕
Mass (Jupiter)
0.812 M♃
Density
0.42 g/cm³
Surface Gravity
1.16 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.156
HZ Position Inner
Controversial No

Discovery

Year 2017
Method Transit
Facility Next-Generation Transit Survey (NGTS)
Telescope 20 cm NGTS telescope

Size rank in cohort

Rank by radius

#237of 1771

top 13.3%

This planet

14.91R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth NGTS-1 b Jupiter
Radius (R⊕)1.0014.9111.21
Mass (M⊕)1.00258.08317.83
Density (g/cm³)5.510.421.33
Surface Gravity (g)1.001.162.53
Insolation (S⊕)1.0065.300.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 258.078 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 192826603

Gaia DR2

Gaia DR2 4821739369794767744

Gaia DR3

Gaia DR3 4821739369794767744

System

NGTS-1

Percentile among Gas Giant cohort

Radius 14.908 R⊕ · percentile 86 / cohort 1771
Mass 258.078 M⊕ · percentile 28 / cohort 1747
Orbital period 2.65 d · percentile 11 / cohort 1533
Distance 218.12 pc · percentile 53 / cohort 1759
ESI 0.156 · percentile 37 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
2.647 days
Semi-major axis
0.0326 AU
Eccentricity
0.016
Inclination
85.27 °

Year Length

A year here lasts approximately 2.65 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0326 AU.

Transit Fingerprint

Depth

2.137 %

Duration

1.230 h

Impact parameter b

0.995

Rp / R★

0.239000

Transit midpoint (BJD)

2,457,720.6594

Photometric dip

Transit produces a flux drop of 21,368 ppm lasting ≈ 1.23 h.

Extended Orbital Architecture

Planet / star radius ratio

0.239000

Semi-major axis / stellar radius

12.200

Impact parameter (b)

0.995

RV semi-amplitude (K)

166.000 m/s

Transit mid-time (BJD)

2,457,720.6594

Angular separation (arcsec)

0.14900

Eq. Temperature

790K

(517 °C)

Insolation (S⊕)

65.30

Earth = 1.00

Earth Similarity (ESI)

0.156

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

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

Bayliss et al. 2018

Instrument

NGTS CCD array

Publication

2018-04

Observation locale

Ground

Host System: NGTS-1

Spectral Class

M-type red dwarf

Effective Temperature

3,916 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.573 R☉

Stellar Mass

0.617 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.710 dex

Stellar density

4.400 g/cm³

Systemic radial velocity

97.18 km/s

Rotational v·sin i

1.00 km/s

Metallicity ratio

[M/H]

Distance
218.12 parsec
Light-years 711.41 ly
V-band magnitude
15.67 mag
Voyager-speed travel 12,545,798 yr

Multi-band Host Photometry — 14 bands

8.816.916.91B15.67V14.87Gaia13.91TESS16.29Sloan g15.00Sloan r14.33Sloan i12.70J12.06H11.94K11.81W111.77W211.75W38.83W4

Astrometric Data

Parallax

4.556 mas

Total Proper Motion

51.969 mas/yr

PM Right Ascension

-31.90 mas/yr

PM Declination

-41.03 mas/yr

Galactic Cartesian (pc)

x = 0.102 · y = 0.796 · z = -0.597

Equatorial (J2000)

RA 82.71421° · Dec -36.63098°

Galactic ℓ, b

241.192° · -31.201°

Ecliptic λ, β

78.332° · -59.776°

HTM-20 index

466939514

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