Key parameters at a glance

A radius of 15.80 Earth radii
A mass of 244.09 Earth masses
Surface gravity around 0.98 g
An orbital period of 3.349 days
Semi-major axis 0.0464 AU
Equilibrium temperature 1,553 K (1280 °C)
Distance from Earth 1,270.61 light-years
Earth Similarity Index 0.070
Travel time at Voyager 1 speed 22,407,134 years

HATS-51 b Planet Profile

Physical Specs

Radius

15.80 R⊕

Radius (Jupiter)

1.410 R♃

Mass

244.09 M⊕

Mass (Jupiter)

0.768 M♃

Density

0.34 g/cm³

Surface Gravity

0.98 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.070

HZ Position Inner

Controversial No

Discovery

Year 2017

Method Transit

Facility HATSouth

Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#174of 1771

top 9.8%

This planet

15.80R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

WASP-61 b 15.80 R⊕ WASP-15 b 15.80 R⊕ WASP-63 b 15.80 R⊕

Metric	Earth	HATS-51 b	Jupiter
Radius (R⊕)	1.00	15.80	11.21
Mass (M⊕)	1.00	244.09	317.83
Density (g/cm³)	5.51	0.34	1.33
Surface Gravity (g)	1.00	0.98	2.53
Insolation (S⊕)	1.00	740.22	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	244.093 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 53458803

Gaia DR2

Gaia DR2 5608644895310998272

Gaia DR3

Gaia DR3 5608644895310998272

System

HATS-51

Percentile among Gas Giant cohort

Radius 15.805 R⊕ · percentile 90 / cohort 1771

Mass 244.093 M⊕ · percentile 26 / cohort 1747

Orbital period 3.35 d · percentile 21 / cohort 1533

Distance 389.57 pc · percentile 68 / cohort 1759

ESI 0.070 · percentile 13 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

3.349 days

Semi-major axis

0.0464 AU

Eccentricity

0.330

Inclination

87.10 °

Year Length

A year here lasts approximately 3.35 Earth days (0.9% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0464 AU.

Transit Fingerprint

Depth

1.099 %

Duration

3.322 h

Impact parameter b

0.300

Rp / R★

0.101000

Transit midpoint (BJD)

2,457,042.0041

Photometric dip

Transit produces a flux drop of 10,987 ppm lasting ≈ 3.32 h.

Extended Orbital Architecture

Planet / star radius ratio

0.101000

Semi-major axis / stellar radius

6.940

Impact parameter (b)

0.300

RV semi-amplitude (K)

94.900 m/s

Transit mid-time (BJD)

2,457,042.0041

Angular separation (arcsec)

0.11900

Eq. Temperature

1,553K

(1280 °C)

Insolation (S⊕)

740.22

Earth = 1.00

Earth Similarity (ESI)

0.070

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

Henning et al. 2018

Instrument

Apogee 4K CCD Sensor

Publication

2018-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2017 at HATSouth (6 shown).

HATS-22 b · Gas Giant HATS-50 b · Gas Giant HATS-53 b · Gas Giant HATS-52 b · Gas Giant HATS-23 b · Gas Giant HATS-24 b · Gas Giant

Host System: HATS-51

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,758 K — cooler than the Sun (5,778 K)

Estimated Age

4.74 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.440 R☉

Stellar Mass

1.187 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

4.198 dex

Stellar density

0.560 g/cm³

Systemic radial velocity

3.09 km/s

Rotational v·sin i

3.98 km/s

Distance

389.57 parsec

Light-years 1,270.61 ly

V-band magnitude

12.53 mag

Voyager-speed travel 22,407,134 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

2.538 mas

Total Proper Motion

17.920 mas/yr

PM Right Ascension

-16.38 mas/yr

PM Declination

-7.26 mas/yr

Galactic Cartesian (pc)

x = -0.194 · y = 0.852 · z = -0.486

Equatorial (J2000)

RA 102.84742° · Dec -29.05866°

Galactic ℓ, b

239.241° · -12.805°

Ecliptic λ, β

108.267° · -51.686°

HTM-20 index

-1972308408