Key parameters at a glance

A radius of 12.59 Earth radii
A mass of 489.46 Earth masses
Surface gravity around 3.09 g
An orbital period of 4.142 days
Semi-major axis 0.0506 AU
Equilibrium temperature 1,278 K (1005 °C)
Distance from Earth 865.85 light-years
Earth Similarity Index 0.117
Travel time at Voyager 1 speed 15,269,257 years

HAT-P-59 b Planet Profile

Physical Specs

Radius

12.59 R⊕

Radius (Jupiter)

1.123 R♃

Mass

489.46 M⊕

Mass (Jupiter)

1.540 M♃

Density

1.35 g/cm³

Surface Gravity

3.09 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.117

HZ Position Inner

Controversial No

Discovery

Year 2021

Method Transit

Facility HATNet

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#1224of 1771

top 69.1%

This planet

12.59R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

WASP-42 b 12.58 R⊕ TOI-3693 b 12.60 R⊕ HATS-2 b 12.58 R⊕

Metric	Earth	HAT-P-59 b	Jupiter
Radius (R⊕)	1.00	12.59	11.21
Mass (M⊕)	1.00	489.46	317.83
Density (g/cm³)	5.51	1.35	1.33
Surface Gravity (g)	1.00	3.09	2.53
Insolation (S⊕)	1.00	441.40	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	489.456 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 229400092

Gaia DR2

Gaia DR2 2241743203599727744

Gaia DR3

Gaia DR3 2241743203599727744

System

HAT-P-59

Percentile among Gas Giant cohort

Radius 12.588 R⊕ · percentile 31 / cohort 1771

Mass 489.456 M⊕ · percentile 48 / cohort 1747

Orbital period 4.14 d · percentile 31 / cohort 1533

Distance 265.47 pc · percentile 57 / cohort 1759

ESI 0.117 · percentile 31 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

4.142 days

Semi-major axis

0.0506 AU

Eccentricity

0.030

Inclination

85.18 °

Year Length

A year here lasts approximately 4.14 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0506 AU.

Transit Fingerprint

Depth

1.013 %

Duration

2.339 h

Impact parameter b

0.830

Rp / R★

0.104520

Transit midpoint (BJD)

2,458,618.5409

Photometric dip

Transit produces a flux drop of 10,131 ppm lasting ≈ 2.34 h.

Extended Orbital Architecture

Planet / star radius ratio

0.104520

Semi-major axis / stellar radius

9.870

Impact parameter (b)

0.830

RV semi-amplitude (K)

192.600 m/s

Transit mid-time (BJD)

2,458,618.5409

Angular separation (arcsec)

0.19100

Eq. Temperature

1,278K

(1005 °C)

Insolation (S⊕)

441.40

Earth = 1.00

Earth Similarity (ESI)

0.117

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

Bakos et al. 2021

Instrument

Apogee 4K CCD Sensor

Publication

2021-07

Observation locale

Ground

Discovery cohort

Planets confirmed in 2021 at HATNet (6 shown).

HAT-P-61 b · Gas Giant HAT-P-63 b · Gas Giant HAT-P-62 b · Gas Giant HAT-P-58 b · Gas Giant HAT-P-60 b · Gas Giant HAT-P-64 b · Gas Giant

Host System: HAT-P-59

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,678 K — cooler than the Sun (5,778 K)

Estimated Age

7.30 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.104 R☉

Stellar Mass

1.008 M☉

Metallicity [Fe/H]

0.22

Extended Stellar Properties

Surface gravity (log g)

4.356 dex

Stellar density

1.059 g/cm³

Systemic radial velocity

-20.48 km/s

Metallicity ratio

[Fe/H]

Distance

265.47 parsec

Light-years 865.85 ly

V-band magnitude

11.64 mag

Voyager-speed travel 15,269,257 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

3.738 mas

Total Proper Motion

21.814 mas/yr

PM Right Ascension

20.96 mas/yr

PM Declination

-6.06 mas/yr

Galactic Cartesian (pc)

x = 0.176 · y = -0.426 · z = 0.887

Equatorial (J2000)

RA 292.45882° · Dec 62.52919°

Galactic ℓ, b

94.055° · 19.640°

Ecliptic λ, β

347.764° · 79.612°

HTM-20 index

666341712