Key parameters at a glance
- A radius of 2.18 Earth radii
- A mass of 6.70 Earth masses
- Surface gravity around 1.41 g
- An orbital period of 8.466 days
- Semi-major axis 0.0749 AU
- Equilibrium temperature 696 K (423 °C)
- Distance from Earth 262.69 light-years
- Earth Similarity Index 0.348
- Travel time at Voyager 1 speed 4,632,508 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around TOI-238
TOI-238 c 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-238 b | Super-Earth | 1.56 | 3.37 | 1.273 | 1,378 | 2024 |
| TOI-238 c this | Sub-Neptune | 2.18 | 6.70 | 8.466 | 696 | 2024 |
TOI-238 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1703of 1978
top 86.0%
This planet
2.18R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-238 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.18 | 11.21 |
| Mass (M⊕) | 1.00 | 6.70 | 317.83 |
| Density (g/cm³) | 5.51 | 1.83 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.41 | 2.53 |
| Insolation (S⊕) | 1.00 | 58.30 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 6.700 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 9006668
Gaia DR2
Gaia DR2 2405081733281425280
Gaia DR3
Gaia DR3 2405081733281425280
System
TOI-238
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 8.47 Earth days (2.3% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0749 AU.
Transit Fingerprint
Rp / R★
0.026700
Transit midpoint (BJD)
2,460,204.9675
Extended Orbital Architecture
Planet / star radius ratio
0.026700
RV semi-amplitude (K)
2.460 m/s
Transit mid-time (BJD)
2,460,204.9675
Angular separation (arcsec)
0.93000
Eq. Temperature
696K
(423 °C)
Insolation (S⊕)
58.30
Earth = 1.00
Earth Similarity (ESI)
0.348
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
Su Aacute Rez Mascare Ntilde O et al. 2024Instrument
Multiple Instruments
Publication
2024-02
Observation locale
Ground
Discovery cohort
Planets confirmed in 2024 at Multiple Observatories (12 shown).
Host System: TOI-238
Spectral Class
K-type orange
Effective Temperature
5,059 K — cooler than the Sun (5,778 K)
Estimated Age
4.30 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.733 R☉
Stellar Mass
0.790 M☉
Metallicity [Fe/H]
-0.11
Extended Stellar Properties
Surface gravity (log g)
4.577 dex
Stellar density
2.640 g/cm³
Rotational v·sin i
1.84 km/s
Rotation period
26.00 days
Activity index (log R'HK)
-4.740
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
12.387 mas
Total Proper Motion
53.238 mas/yr
PM Right Ascension
-53.24 mas/yr
PM Declination
-0.20 mas/yr
Galactic Cartesian (pc)
x = 0.931 · y = -0.177 · z = -0.319
Equatorial (J2000)
RA 349.23108° · Dec -18.60665°
Galactic ℓ, b
49.354° · -66.671°
Ecliptic λ, β
342.730° · -12.844°
HTM-20 index
986030315
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Kepler-250 d
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