Confirmed Exoplanet Discovered 2021

HATS-75 b

A neptune-like orbiting the k-type orange HATS-75, located approximately 635.9 light-years from Earth.

Key parameters at a glance

  • A radius of 9.91 Earth radii
  • A mass of 156.05 Earth masses
  • Surface gravity around 1.59 g
  • An orbital period of 2.789 days
  • Semi-major axis 0.0327 AU
  • Equilibrium temperature 772 K (499 °C)
  • Distance from Earth 635.89 light-years
  • Earth Similarity Index 0.202
  • Travel time at Voyager 1 speed 11,213,863 years
  • Almost certainly tidally locked to its host star given the close orbit

HATS-75 b Planet Profile

Physical Specs

Radius
9.91 R⊕
Radius (Jupiter)
0.884 R♃
Mass
156.05 M⊕
Mass (Jupiter)
0.491 M♃
Density
0.88 g/cm³
Surface Gravity
1.59 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.202
HZ Position Inner
Controversial No

Discovery

Year 2021
Method Transit
Facility HATSouth
Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#10of 574

top 1.6%

This planet

9.91R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth HATS-75 b Jupiter
Radius (R⊕)1.009.9111.21
Mass (M⊕)1.00156.05317.83
Density (g/cm³)5.510.881.33
Surface Gravity (g)1.001.592.53
Insolation (S⊕)1.0059.260.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 156.054 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 44737596

Gaia DR2

Gaia DR2 5082914338199586560

Gaia DR3

Gaia DR3 5082914338199586560

System

HATS-75

Percentile among Neptune-like cohort

Radius 9.909 R⊕ · percentile 98 / cohort 574
Mass 156.054 M⊕ · percentile 94 / cohort 574
Orbital period 2.79 d · percentile 3 / cohort 524
Distance 194.96 pc · percentile 39 / cohort 572
ESI 0.202 · percentile 29 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
2.789 days
Semi-major axis
0.0327 AU
Eccentricity
0.064
Inclination
88.07 °

Year Length

A year here lasts approximately 2.79 Earth days (0.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0327 AU.

Transit Fingerprint

Depth

2.634 %

Duration

1.913 h

Impact parameter b

0.406

Rp / R★

0.155500

Transit midpoint (BJD)

2,458,611.0549

Photometric dip

Transit produces a flux drop of 26,340 ppm lasting ≈ 1.91 h.

Extended Orbital Architecture

Planet / star radius ratio

0.155500

Semi-major axis / stellar radius

12.037

Impact parameter (b)

0.406

RV semi-amplitude (K)

99.200 m/s

Transit mid-time (BJD)

2,458,611.0549

Angular separation (arcsec)

0.16800

Eq. Temperature

772K

(499 °C)

Insolation (S⊕)

59.26

Earth = 1.00

Earth Similarity (ESI)

0.202

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

Jord Aacute N et al. 2022

Instrument

Apogee 4K CCD Sensor

Publication

2022-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2021 at HATSouth (3 shown).

Host System: HATS-75

Spectral Class

K-type orange

Effective Temperature

3,790 K — cooler than the Sun (5,778 K)

Estimated Age

14.90 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.585 R☉

Stellar Mass

0.602 M☉

Metallicity [Fe/H]

0.52

Extended Stellar Properties

Surface gravity (log g)

4.683 dex

Stellar density

4.239 g/cm³

Systemic radial velocity

40.00 km/s

Rotation period

35.04 days

Metallicity ratio

[Fe/H]

Distance
194.96 parsec
Light-years 635.89 ly
V-band magnitude
15.69 mag
Voyager-speed travel 11,213,863 yr

Multi-band Host Photometry — 11 bands

9.017.117.12B15.69V14.90Gaia13.82TESS12.48J11.76H11.58K11.49W111.50W211.61W38.99W4

Astrometric Data

Parallax

5.100 mas

Total Proper Motion

12.990 mas/yr

PM Right Ascension

12.87 mas/yr

PM Declination

-1.75 mas/yr

Galactic Cartesian (pc)

x = 0.439 · y = 0.790 · z = -0.429

Equatorial (J2000)

RA 60.94939° · Dec -25.40892°

Galactic ℓ, b

221.956° · -47.107°

Ecliptic λ, β

51.617° · -45.053°

HTM-20 index

1026663152

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