Key parameters at a glance

A radius of 9.75 Earth radii
A mass of 68.60 Earth masses
Surface gravity around 0.72 g
An orbital period of 63.483 days
Semi-major axis 0.3370 AU
Equilibrium temperature 615 K (342 °C)
Distance from Earth 731.85 light-years
Earth Similarity Index 0.222
Travel time at Voyager 1 speed 12,906,088 years

TOI-1859 b Planet Profile

Physical Specs

Radius

9.75 R⊕

Radius (Jupiter)

0.870 R♃

Mass

68.60 M⊕

Mass (Jupiter)

0.216 M♃

Density

0.41 g/cm³

Surface Gravity

0.72 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.222

HZ Position Inner

Controversial No

Discovery

Year 2023

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#21of 574

top 3.5%

This planet

9.75R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-5573 b 9.75 R⊕ Kepler-688 b 9.76 R⊕ Kepler-1517 b 9.76 R⊕

Metric	Earth	TOI-1859 b	Jupiter
Radius (R⊕)	1.00	9.75	11.21
Mass (M⊕)	1.00	68.60	317.83
Density (g/cm³)	5.51	0.41	1.33
Surface Gravity (g)	1.00	0.72	2.53
Insolation (S⊕)	1.00	23.79	0.037

Star Catalogue Identifiers

TIC

TIC 229742722

Gaia DR2

Gaia DR2 2259354802894412928

Gaia DR3

Gaia DR3 2259354802894412928

System

TOI-1859

Percentile among Neptune-like cohort

Radius 9.752 R⊕ · percentile 96 / cohort 574

Mass 68.600 M⊕ · percentile 85 / cohort 574

Orbital period 63.48 d · percentile 74 / cohort 524

Distance 224.39 pc · percentile 42 / cohort 572

ESI 0.222 · percentile 33 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

63.483 days

Semi-major axis

0.3370 AU

Eccentricity

0.570

Inclination

88.64 °

Year Length

A year here lasts approximately 63.48 Earth days (17.4% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.3370 AU.

Transit Fingerprint

Depth

0.536 %

Duration

5.457 h

Impact parameter b

0.610

Rp / R★

0.066000

Transit midpoint (BJD)

2,458,662.6558

Photometric dip

Transit produces a flux drop of 5,357 ppm lasting ≈ 5.46 h.

Extended Orbital Architecture

Planet / star radius ratio

0.066000

Semi-major axis / stellar radius

53.700

Impact parameter (b)

0.610

Transit mid-time (BJD)

2,458,662.6558

Long. of periastron (ω)

79.90°

Sky-projected obliquity (λ)

38.90°

Angular separation (arcsec)

1.50000

Eq. Temperature

615K

(342 °C)

Insolation (S⊕)

23.79

Earth = 1.00

Earth Similarity (ESI)

0.222

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Dong et al. 2023

Instrument

TESS CCD Array

Publication

2023-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-700 e · Rocky Terrestrial TOI-2095 c · Super-Earth TOI-715 b · Super-Earth TOI-2095 b · Super-Earth TOI-2096 c · Super-Earth TOI-1680 b · Super-Earth TOI-2096 b · Rocky Terrestrial TOI-904 c · Sub-Neptune TOI-1470 c · Sub-Neptune TOI-198 b · Super-Earth TOI-244 b · Super-Earth TOI-4184 b · Sub-Neptune

Host System: TOI-1859

Spectral Class

F-type yellow-white

Effective Temperature

6,341 K — hotter than the Sun (5,778 K)

Estimated Age

1.41 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.360 R☉

Stellar Mass

1.287 M☉

Metallicity [Fe/H]

0.12

Extended Stellar Properties

Surface gravity (log g)

4.285 dex

Stellar density

0.730 g/cm³

Rotational v·sin i

12.49 km/s

Metallicity ratio

[M/H]

Distance

224.39 parsec

Light-years 731.85 ly

V-band magnitude

10.33 mag

Voyager-speed travel 12,906,088 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

4.428 mas

Total Proper Motion

17.166 mas/yr

PM Right Ascension

12.12 mas/yr

PM Declination

-12.16 mas/yr

Galactic Cartesian (pc)

x = 0.060 · y = -0.345 · z = 0.937

Equatorial (J2000)

RA 279.83176° · Dec 69.52287°

Galactic ℓ, b

99.990° · 26.335°

Ecliptic λ, β

43.346° · 85.288°

HTM-20 index

-580247382