Key parameters at a glance
- A radius of 9.86 Earth radii
- A mass of 657.00 Earth masses
- Surface gravity around 6.76 g
- An orbital period of 4.291 days
- Semi-major axis 0.0469 AU
- Equilibrium temperature 783 K (510 °C)
- Distance from Earth 1,231.18 light-years
- Earth Similarity Index 0.160
- Travel time at Voyager 1 speed 21,711,919 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-5218 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#14of 574
top 2.3%
This planet
9.86R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | TOI-5218 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 9.86 | 11.21 |
| Mass (M⊕) | 1.00 | 657.00 | 317.83 |
| Density (g/cm³) | 5.51 | — | 1.33 |
| Surface Gravity (g) | 1.00 | 6.76 | 2.53 |
| Insolation (S⊕) | 1.00 | 62.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 657.000 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 259172249
Gaia DR2
Gaia DR2 2263568371970517120
Gaia DR3
Gaia DR3 2263568371970517120
System
TOI-5218
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.29 Earth days (1.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0469 AU.
Transit Fingerprint
Depth
1.918 %
Duration
2.380 h
Impact parameter b
0.400
Rp / R★
0.130000
Transit midpoint (BJD)
2,458,842.6521
Photometric dip
Transit produces a flux drop of 19,181 ppm lasting ≈ 2.38 h.
Extended Orbital Architecture
Planet / star radius ratio
0.130000
Semi-major axis / stellar radius
14.560
Impact parameter (b)
0.400
RV semi-amplitude (K)
309.000 m/s
Transit mid-time (BJD)
2,458,842.6521
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
0.12400
Eq. Temperature
783K
(510 °C)
Insolation (S⊕)
62.00
Earth = 1.00
Earth Similarity (ESI)
0.160
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.
Discovery Paper
Primary reference
Kanodia et al. 2024Instrument
TESS CCD Array
Publication
2024-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2024 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-5218
Spectral Class
K-type orange
Effective Temperature
4,230 K — cooler than the Sun (5,778 K)
Estimated Age
6.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.708 R☉
Stellar Mass
0.739 M☉
Metallicity [Fe/H]
0.41
Extended Stellar Properties
Surface gravity (log g)
4.630 dex
Stellar density
2.940 g/cm³
Rotational v·sin i
2.00 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
2.620 mas
Total Proper Motion
19.153 mas/yr
PM Right Ascension
7.89 mas/yr
PM Declination
17.45 mas/yr
Galactic Cartesian (pc)
x = 0.121 · y = -0.289 · z = 0.950
Equatorial (J2000)
RA 292.66346° · Dec 71.76296°
Galactic ℓ, b
103.406° · 22.684°
Ecliptic λ, β
43.096° · 80.494°
HTM-20 index
1162806961
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