Confirmed Exoplanet Discovered 2018

HATS-40 b

A gas giant orbiting the f-type yellow-white HATS-40, located approximately 4,378.0 light-years from Earth.

Key parameters at a glance

  • A radius of 17.71 Earth radii
  • A mass of 505.35 Earth masses
  • Surface gravity around 1.61 g
  • An orbital period of 3.264 days
  • Semi-major axis 0.0500 AU
  • Equilibrium temperature 2,101 K (1828 °C)
  • Distance from Earth 4,377.96 light-years
  • Earth Similarity Index 0.050
  • Travel time at Voyager 1 speed 77,205,309 years

HATS-40 b Planet Profile

Physical Specs

Radius
17.71 R⊕
Radius (Jupiter)
1.580 R♃
Mass
505.35 M⊕
Mass (Jupiter)
1.590 M♃
Density
0.49 g/cm³
Surface Gravity
1.61 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.050
HZ Position Inner
Controversial No

Discovery

Year 2018
Method Transit
Facility HATSouth
Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#85of 1771

top 4.7%

This planet

17.71R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth HATS-40 b Jupiter
Radius (R⊕)1.0017.7111.21
Mass (M⊕)1.00505.35317.83
Density (g/cm³)5.510.491.33
Surface Gravity (g)1.001.612.53
Insolation (S⊕)1.003,163.380.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 505.350 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 172598832

Gaia DR2

Gaia DR2 2894378838731535872

Gaia DR3

Gaia DR3 2894378838731535872

System

HATS-40

Percentile among Gas Giant cohort

Radius 17.710 R⊕ · percentile 95 / cohort 1771
Mass 505.350 M⊕ · percentile 49 / cohort 1747
Orbital period 3.26 d · percentile 19 / cohort 1533
Distance 1,342.29 pc · percentile 89 / cohort 1759
ESI 0.050 · percentile 4 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
3.264 days
Semi-major axis
0.0500 AU
Eccentricity
0.312
Inclination
85.80 °

Year Length

A year here lasts approximately 3.26 Earth days (0.9% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0500 AU.

Transit Fingerprint

Depth

0.501 %

Duration

5.330 h

Impact parameter b

0.350

Rp / R★

0.071600

Transit midpoint (BJD)

2,456,962.6760

Photometric dip

Transit produces a flux drop of 5,012 ppm lasting ≈ 5.33 h.

Extended Orbital Architecture

Planet / star radius ratio

0.071600

Semi-major axis / stellar radius

4.740

Impact parameter (b)

0.350

RV semi-amplitude (K)

162.000 m/s

Transit mid-time (BJD)

2,456,962.6760

Angular separation (arcsec)

0.03720

Eq. Temperature

2,101K

(1828 °C)

Insolation (S⊕)

3,163.38

Earth = 1.00

Earth Similarity (ESI)

0.050

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

Bento et al. 2018

Instrument

Apogee 4K CCD Sensor

Publication

2018-07

Observation locale

Ground

Host System: HATS-40

Spectral Class

F-type yellow-white

Effective Temperature

6,460 K — hotter than the Sun (5,778 K)

Estimated Age

2.07 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.260 R☉

Stellar Mass

1.561 M☉

Metallicity [Fe/H]

0.01

Extended Stellar Properties

Surface gravity (log g)

3.921 dex

Stellar density

0.189 g/cm³

Systemic radial velocity

9.19 km/s

Rotational v·sin i

9.52 km/s

Metallicity ratio

[Fe/H]

Distance
1,342.29 parsec
Light-years 4,377.96 ly
V-band magnitude
13.48 mag
Voyager-speed travel 77,205,309 yr

Multi-band Host Photometry — 14 bands

8.413.913.86B13.48V13.28Gaia12.94TESS13.56Sloan g13.27Sloan r13.20Sloan i12.44J12.24H12.15K12.13W112.13W211.57W38.37W4

Astrometric Data

Parallax

0.716 mas

Total Proper Motion

7.083 mas/yr

PM Right Ascension

-4.34 mas/yr

PM Declination

5.59 mas/yr

Galactic Cartesian (pc)

x = -0.159 · y = 0.853 · z = -0.497

Equatorial (J2000)

RA 100.57125° · Dec -29.77678°

Galactic ℓ, b

239.102° · -14.910°

Ecliptic λ, β

105.216° · -52.659°

HTM-20 index

1369058199

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