Key parameters at a glance

A radius of 7.34 Earth radii
A mass of 42.32 Earth masses
Surface gravity around 0.79 g
Semi-major axis 1.6000 AU
Distance from Earth 24,461.70 light-years
Earth Similarity Index 0.374
Travel time at Voyager 1 speed 431,382,055 years

KMT-2025-BLG-1616L b Planet Profile

Physical Specs

Radius

7.34 R⊕

Radius (Jupiter)

0.655 R♃

Mass

42.32 M⊕

Mass (Jupiter)

0.133 M♃

Density

0.59 g/cm³

Surface Gravity

0.79 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.374

HZ Position Unknown

Controversial No

Discovery

Year 2026

Method Microlensing

Facility KMTNet

Telescope 1.6 m wide-field telescope

Size rank in cohort

Rank by radius

#183of 574

top 31.7%

This planet

7.34R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

K2-387 b 7.32 R⊕ TOI-1203 e 7.31 R⊕ TOI-7510 b 7.31 R⊕

Metric	Earth	KMT-2025-BLG-1616L b	Jupiter
Radius (R⊕)	1.00	7.34	11.21
Mass (M⊕)	1.00	42.32	317.83
Density (g/cm³)	5.51	0.59	1.33
Surface Gravity (g)	1.00	0.79	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	42.320 M⊕	Direct mass measurement (not derived).

Percentile among Neptune-like cohort

Radius 7.340 R⊕ · percentile 68 / cohort 574

Mass 42.320 M⊕ · percentile 65 / cohort 574

Distance 7,500.00 pc · percentile 99 / cohort 572

ESI 0.374 · percentile 68 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

— days

Semi-major axis

1.6000 AU

Eccentricity

—

Inclination

— °

Year Length

Orbital period for this planet has not yet been measured.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.374

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Yang et al. 2026

Instrument

18k Mosaic CCD camera

Publication

2026-01

Observation locale

Ground

Discovery cohort

Planets confirmed in 2026 at KMTNet (12 shown).

KMT-2024-BLG-2087L b · Gas Giant KMT-2025-BLG-0121L b · Gas Giant KMT-2022-BLG-1818L b · Gas Giant KMT-2023-BLG-0466L b · Gas Giant KMT-2022-BLG-1551L b · Gas Giant KMT-2024-BLG-0349L b · Gas Giant KMT-2020-BLG-0202L b · Gas Giant KMT-2024-BLG-2005L b · Neptune-like KMT-2024-BLG-1870L b · Gas Giant KMT-2024-BLG-0176L b · Gas Giant KMT-2016-BLG-1337L b · Gas Giant KMT-2025-BLG-0481L b · Gas Giant

Host System: KMT-2025-BLG-1616L

Spectral Class

M-type red dwarf

Effective Temperature

—

Estimated Age

—

Stellar Radius

—

Stellar Mass

0.260 M☉

Metallicity [Fe/H]

—

Distance

7,500.00 parsec

Light-years 24,461.70 ly

V-band magnitude

— mag

Voyager-speed travel 431,382,055 yr