Key parameters at a glance

A radius of 2.10 Earth radii
A mass of 9.10 Earth masses
Surface gravity around 2.06 g
An orbital period of 6.184 days
Semi-major axis 0.0592 AU
Equilibrium temperature 688 K (415 °C)
Distance from Earth 106.03 light-years
Earth Similarity Index 0.416
Travel time at Voyager 1 speed 1,869,909 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

TOI-5734 b is a confirmed exoplanet orbiting the young orange dwarf star TOI-5734, a K3-K4 spectral class star, at a distance of approximately 106 light-years from the Sun. The discovery of the object was officially announced by an international team of astronomers led by Simone Filomeno in late February 2026.

Excerpted from Wikipedia · full article

TOI-5734 b Planet Profile

Physical Specs

Radius

2.10 R⊕

Radius (Jupiter)

0.187 R♃

Mass

9.10 M⊕

Mass (Jupiter)

0.029 M♃

Density

5.40 g/cm³

Surface Gravity

2.06 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.416

HZ Position Inner

Controversial No

Discovery

Year 2026

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#1818of 1978

top 91.9%

This planet

2.10R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1529 b 2.10 R⊕ Kepler-52 b 2.10 R⊕ Kepler-360 c 2.10 R⊕

Metric	Earth	TOI-5734 b	Jupiter
Radius (R⊕)	1.00	2.10	11.21
Mass (M⊕)	1.00	9.10	317.83
Density (g/cm³)	5.51	5.40	1.33
Surface Gravity (g)	1.00	2.06	2.53
Insolation (S⊕)	1.00	56.38	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	9.100 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 9989136

Gaia DR2

Gaia DR2 898844639674672640

Gaia DR3

Gaia DR3 898844639674672640

System

TOI-5734

Percentile among Sub-Neptune cohort

Radius 2.100 R⊕ · percentile 7 / cohort 1978

Mass 9.100 M⊕ · percentile 66 / cohort 1978

Orbital period 6.18 d · percentile 18 / cohort 1946

Distance 32.51 pc · percentile 8 / cohort 1975

ESI 0.416 · percentile 56 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

6.184 days

Semi-major axis

0.0592 AU

Eccentricity

—

Inclination

89.88 °

Year Length

A year here lasts approximately 6.18 Earth days (1.7% of a terrestrial year) at a mean orbital distance of 0.0592 AU.

Transit Fingerprint

Depth

0.105 %

Duration

2.390 h

Impact parameter b

0.040

Rp / R★

0.030110

Transit midpoint (BJD)

2,458,842.5107

Photometric dip

Transit produces a flux drop of 1,052 ppm lasting ≈ 2.39 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030110

Semi-major axis / stellar radius

18.490

Impact parameter (b)

0.040

RV semi-amplitude (K)

3.900 m/s

Transit mid-time (BJD)

2,458,842.5107

Angular separation (arcsec)

1.82000

Eq. Temperature

688K

(415 °C)

Insolation (S⊕)

56.38

Earth = 1.00

Earth Similarity (ESI)

0.416

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

Morello et al. 2026

Instrument

TESS CCD Array

Publication

2026-01

Observation locale

Space

Discovery cohort

Planets confirmed in 2026 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-2094 b · Super-Earth TOI-6716 b · Rocky Terrestrial TOI-1080 b · Rocky Terrestrial TOI-1243 b · Sub-Neptune TOI-4529 b · Super-Earth TOI-7384 b · Sub-Neptune LHS 1903 d · Sub-Neptune LHS 1903 c · Sub-Neptune TOI-5788 c · Sub-Neptune LHS 1903 b · Super-Earth TOI-5788 b · Super-Earth TOI-1232 c · Neptune-like

Host System: TOI-5734

Spectral Class

K-type orange

Effective Temperature

4,750 K — cooler than the Sun (5,778 K)

Estimated Age

0.50 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.639 R☉

Stellar Mass

0.724 M☉

Metallicity [Fe/H]

-0.13

Extended Stellar Properties

Surface gravity (log g)

4.660 dex

Stellar density

3.119 g/cm³

Systemic radial velocity

-9.18 km/s

Rotational v·sin i

2.90 km/s

Rotation period

11.09 days

Activity index (log R'HK)

-4.470

Metallicity ratio

[Fe/H]

Distance

32.51 parsec

Light-years 106.03 ly

V-band magnitude

9.61 mag

Voyager-speed travel 1,869,909 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

30.731 mas

Total Proper Motion

31.145 mas/yr

PM Right Ascension

-27.64 mas/yr

PM Declination

14.35 mas/yr

Galactic Cartesian (pc)

x = -0.289 · y = 0.742 · z = 0.605

Equatorial (J2000)

RA 111.25582° · Dec 37.23112°

Galactic ℓ, b

181.285° · 22.294°

Ecliptic λ, β

107.389° · 15.067°

HTM-20 index

1689585104

Wikipedia →

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