Key parameters at a glance
- A radius of 3.04 Earth radii
- A mass of 9.40 Earth masses
- Surface gravity around 1.02 g
- An orbital period of 5.140 days
- Semi-major axis 0.0553 AU
- Equilibrium temperature 971 K (698 °C)
- Distance from Earth 360.44 light-years
- Earth Similarity Index 0.238
- Travel time at Voyager 1 speed 6,356,443 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around TOI-1438
TOI-1438 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| TOI-1438 b this | Sub-Neptune | 3.04 | 9.40 | 5.140 | 971 | 2025 |
| TOI-1438 c | Sub-Neptune | 2.75 | 10.60 | 9.428 | 794 | 2025 |
TOI-1438 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#481of 1978
top 24.3%
This planet
3.04R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-1438 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.04 | 11.21 |
| Mass (M⊕) | 1.00 | 9.40 | 317.83 |
| Density (g/cm³) | 5.51 | 1.80 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.02 | 2.53 |
| Insolation (S⊕) | 1.00 | 145.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 9.400 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 229650439
Gaia DR2
Gaia DR2 2268101727131230464
Gaia DR3
Gaia DR3 2268101727131230464
System
TOI-1438
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.14 Earth days (1.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0553 AU.
Transit Fingerprint
Depth
0.077 %
Duration
1.040 h
Impact parameter b
0.956
Rp / R★
0.034100
Transit midpoint (BJD)
2,458,683.6256
Photometric dip
Transit produces a flux drop of 770 ppm lasting ≈ 1.04 h.
Extended Orbital Architecture
Planet / star radius ratio
0.034100
Semi-major axis / stellar radius
14.500
Impact parameter (b)
0.956
RV semi-amplitude (K)
3.800 m/s
Transit mid-time (BJD)
2,458,683.6256
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
0.50000
Eq. Temperature
971K
(698 °C)
Insolation (S⊕)
145.00
Earth = 1.00
Earth Similarity (ESI)
0.238
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
Persson et al. 2025Instrument
TESS CCD Array
Publication
2025-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-1438
Spectral Class
K-type orange
Effective Temperature
5,230 K — cooler than the Sun (5,778 K)
Estimated Age
2.20 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.820 R☉
Stellar Mass
0.876 M☉
Metallicity [Fe/H]
0.03
Extended Stellar Properties
Surface gravity (log g)
4.500 dex
Stellar density
2.200 g/cm³
Systemic radial velocity
-29.40 km/s
Rotational v·sin i
1.80 km/s
Activity index (log R'HK)
-4.925
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
9.020 mas
Total Proper Motion
58.079 mas/yr
PM Right Ascension
-23.08 mas/yr
PM Declination
53.29 mas/yr
Galactic Cartesian (pc)
x = 0.049 · y = -0.255 · z = 0.966
Equatorial (J2000)
RA 280.92378° · Dec 74.93783°
Galactic ℓ, b
106.043° · 26.624°
Ecliptic λ, β
71.822° · 80.916°
HTM-20 index
1647446786
Similar Worlds
Kepler-676 b
Sub-Neptune · K-type orange
Radius 3.04 R⊕ · 962.8 ly
HD 216520 c
Sub-Neptune · K-type orange
Radius 3.03 R⊕ · 63.8 ly
K2-273 b
Sub-Neptune · K-type orange
Radius 3.05 R⊕ · 1,004.9 ly
Kepler-245 d
Sub-Neptune · K-type orange
Radius 3.03 R⊕ · 2,809.9 ly
TOI-220 b
Sub-Neptune · K-type orange
Radius 3.03 R⊕ · 296.0 ly
Kepler-248 b
Sub-Neptune · K-type orange
Radius 3.02 R⊕ · 2,409.6 ly