Key parameters at a glance
- A radius of 2.27 Earth radii
- A mass of 9.20 Earth masses
- Surface gravity around 1.79 g
- An orbital period of 7.436 days
- Equilibrium temperature 576 K (303 °C)
- Distance from Earth 91.31 light-years
- Earth Similarity Index 0.476
- Travel time at Voyager 1 speed 1,610,240 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-2018 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1568of 1978
top 79.2%
This planet
2.27R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-2018 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.27 | 11.21 |
| Mass (M⊕) | 1.00 | 9.20 | 317.83 |
| Density (g/cm³) | 5.51 | 4.33 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.79 | 2.53 |
| Insolation (S⊕) | 1.00 | 26.08 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 9.200 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
HIP
HIP 74981
TIC
TIC 357501308
Gaia DR2
Gaia DR2 1272123859439770368
Gaia DR3
Gaia DR3 1272123859439770368
System
TOI-2018
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 7.44 Earth days (2.0% of a terrestrial year) on a nearly circular orbit.
Transit Fingerprint
Depth
0.131 %
Duration
2.360 h
Impact parameter b
0.546
Rp / R★
0.033500
Transit midpoint (BJD)
2,458,958.2580
Photometric dip
Transit produces a flux drop of 1,311 ppm lasting ≈ 2.36 h.
Extended Orbital Architecture
Planet / star radius ratio
0.033500
Semi-major axis / stellar radius
21.120
Impact parameter (b)
0.546
RV semi-amplitude (K)
4.400 m/s
Transit mid-time (BJD)
2,458,958.2580
Eq. Temperature
576K
(303 °C)
Insolation (S⊕)
26.08
Earth = 1.00
Earth Similarity (ESI)
0.476
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
Dai et al. 2023Instrument
TESS CCD Array
Publication
2023-06
Observation locale
Space
Discovery cohort
Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-2018
Spectral Class
K-type orange
Effective Temperature
4,174 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.620 R☉
Stellar Mass
0.570 M☉
Metallicity [Fe/H]
-0.58
Extended Stellar Properties
Surface gravity (log g)
4.620 dex
Stellar density
3.229 g/cm³
Rotational v·sin i
2.00 km/s
Rotation period
23.50 days
Activity index (log R'HK)
-4.750
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
35.691 mas
Total Proper Motion
419.917 mas/yr
PM Right Ascension
-141.10 mas/yr
PM Declination
395.50 mas/yr
Galactic Cartesian (pc)
x = -0.563 · y = -0.667 · z = 0.488
Equatorial (J2000)
RA 229.83744° · Dec 29.20788°
Galactic ℓ, b
45.426° · 57.468°
Ecliptic λ, β
216.584° · 45.484°
HTM-20 index
-1327903545
Similar Worlds
Kepler-1503 b
Sub-Neptune · K-type orange
Radius 2.27 R⊕ · 3,997.3 ly
Kepler-306 e
Sub-Neptune · K-type orange
Radius 2.27 R⊕ · 2,529.9 ly
EPIC 212297394 c
Sub-Neptune · K-type orange
Radius 2.27 R⊕ · 1,364.6 ly
K2-401 b
Sub-Neptune · K-type orange
Radius 2.26 R⊕ · 654.7 ly
Kepler-1996 b
Sub-Neptune · K-type orange
Radius 2.26 R⊕ · 1,436.9 ly
K2-346 b
Sub-Neptune · K-type orange
Radius 2.26 R⊕ · 344.4 ly