Key parameters at a glance
- A radius of 9.86 Earth radii
- A mass of 190.70 Earth masses
- Surface gravity around 1.96 g
- An orbital period of 2.262 days
- Semi-major axis 0.0295 AU
- Equilibrium temperature 1,043 K (770 °C)
- Distance from Earth 530.04 light-years
- Earth Similarity Index 0.153
- Travel time at Voyager 1 speed 9,347,186 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-5300 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#12of 574
top 1.9%
This planet
9.86R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | TOI-5300 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 9.86 | 11.21 |
| Mass (M⊕) | 1.00 | 190.70 | 317.83 |
| Density (g/cm³) | 5.51 | 1.10 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.96 | 2.53 |
| Insolation (S⊕) | 1.00 | 198.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 190.697 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 267215820
Gaia DR2
Gaia DR2 2642766361608754432
Gaia DR3
Gaia DR3 2642766361608754432
System
TOI-5300
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.26 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0295 AU.
Transit Fingerprint
Depth
2.447 %
Duration
2.360 h
Impact parameter b
0.130
Rp / R★
0.138900
Transit midpoint (BJD)
2,459,470.4174
Photometric dip
Transit produces a flux drop of 24,470 ppm lasting ≈ 2.36 h.
Extended Orbital Architecture
Planet / star radius ratio
0.138900
Impact parameter (b)
0.130
RV semi-amplitude (K)
121.000 m/s
Transit mid-time (BJD)
2,459,470.4174
Angular separation (arcsec)
0.18200
Eq. Temperature
1,043K
(770 °C)
Insolation (S⊕)
198.00
Earth = 1.00
Earth Similarity (ESI)
0.153
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. 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
Frensch et al. 2025Instrument
TESS CCD Array
Publication
2025-06
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-5300
Spectral Class
K-type orange
Effective Temperature
4,610 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.650 R☉
Stellar Mass
0.670 M☉
Metallicity [Fe/H]
-0.17
Extended Stellar Properties
Surface gravity (log g)
4.640 dex
Stellar density
3.003 g/cm³
Systemic radial velocity
-66.61 km/s
Rotational v·sin i
2.00 km/s
Rotation period
31.00 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
6.125 mas
Total Proper Motion
46.915 mas/yr
PM Right Ascension
16.14 mas/yr
PM Declination
-44.05 mas/yr
Galactic Cartesian (pc)
x = 0.998 · y = -0.061 · z = 0.008
Equatorial (J2000)
RA 356.48114° · Dec 0.45880°
Galactic ℓ, b
90.548° · -58.233°
Ecliptic λ, β
356.949° · 1.820°
HTM-20 index
-1701294394
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Neptune-like · K-type orange
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