Confirmed Exoplanet Discovered 2018

HATS-42 b

A gas giant orbiting the f-type yellow-white HATS-42, located approximately 2,610.5 light-years from Earth.

Key parameters at a glance

  • A radius of 15.69 Earth radii
  • A mass of 597.52 Earth masses
  • Surface gravity around 2.43 g
  • An orbital period of 2.292 days
  • Semi-major axis 0.0369 AU
  • Equilibrium temperature 1,856 K (1583 °C)
  • Distance from Earth 2,610.48 light-years
  • Earth Similarity Index 0.066
  • Travel time at Voyager 1 speed 46,035,770 years

HATS-42 b Planet Profile

Physical Specs

Radius
15.69 R⊕
Radius (Jupiter)
1.400 R♃
Mass
597.52 M⊕
Mass (Jupiter)
1.880 M♃
Density
0.83 g/cm³
Surface Gravity
2.43 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.066
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

#180of 1771

top 10.1%

This planet

15.69R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth HATS-42 b Jupiter
Radius (R⊕)1.0015.6911.21
Mass (M⊕)1.00597.52317.83
Density (g/cm³)5.510.831.33
Surface Gravity (g)1.002.432.53
Insolation (S⊕)1.001,637.210.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 597.520 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 98283926

Gaia DR2

Gaia DR2 5603100779728361088

Gaia DR3

Gaia DR3 5603100779728361088

System

HATS-42

Percentile among Gas Giant cohort

Radius 15.693 R⊕ · percentile 90 / cohort 1771
Mass 597.520 M⊕ · percentile 53 / cohort 1747
Orbital period 2.29 d · percentile 9 / cohort 1533
Distance 800.38 pc · percentile 83 / cohort 1759
ESI 0.066 · percentile 11 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
2.292 days
Semi-major axis
0.0369 AU
Eccentricity
0.229
Inclination
85.10 °

Year Length

A year here lasts approximately 2.29 Earth days (0.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0369 AU.

Transit Fingerprint

Depth

1.059 %

Duration

3.266 h

Impact parameter b

0.460

Rp / R★

0.097600

Transit midpoint (BJD)

2,456,768.6073

Photometric dip

Transit produces a flux drop of 10,585 ppm lasting ≈ 3.27 h.

Extended Orbital Architecture

Planet / star radius ratio

0.097600

Semi-major axis / stellar radius

5.360

Impact parameter (b)

0.460

RV semi-amplitude (K)

246.000 m/s

Transit mid-time (BJD)

2,456,768.6073

Angular separation (arcsec)

0.04610

Eq. Temperature

1,856K

(1583 °C)

Insolation (S⊕)

1,637.21

Earth = 1.00

Earth Similarity (ESI)

0.066

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-42

Spectral Class

F-type yellow-white

Effective Temperature

6,060 K — hotter than the Sun (5,778 K)

Estimated Age

3.26 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.480 R☉

Stellar Mass

1.273 M☉

Metallicity [Fe/H]

0.22

Extended Stellar Properties

Surface gravity (log g)

4.201 dex

Stellar density

0.550 g/cm³

Systemic radial velocity

8.16 km/s

Rotational v·sin i

6.04 km/s

Metallicity ratio

[Fe/H]

Distance
800.38 parsec
Light-years 2,610.48 ly
V-band magnitude
13.68 mag
Voyager-speed travel 46,035,770 yr

Multi-band Host Photometry — 14 bands

9.214.214.24B13.68V13.56Gaia13.15TESS13.92Sloan g13.50Sloan r13.40Sloan i12.54J12.28H12.25K12.17W112.19W212.12W39.19W4

Astrometric Data

Parallax

1.221 mas

Total Proper Motion

2.977 mas/yr

PM Right Ascension

0.76 mas/yr

PM Declination

-2.88 mas/yr

Galactic Cartesian (pc)

x = -0.264 · y = 0.792 · z = -0.551

Equatorial (J2000)

RA 108.45240° · Dec -33.43735°

Galactic ℓ, b

245.353° · -10.304°

Ecliptic λ, β

117.510° · -55.128°

HTM-20 index

-786065029

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