Key parameters at a glance
- A radius of 2.73 Earth radii
- A mass of 9.50 Earth masses
- Surface gravity around 1.28 g
- An orbital period of 4.654 days
- Semi-major axis 0.0519 AU
- Equilibrium temperature 1,037 K (764 °C)
- Distance from Earth 362.23 light-years
- Earth Similarity Index 0.238
- Travel time at Voyager 1 speed 6,387,848 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around TOI-125
TOI-125 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.
TOI-125 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#837of 1978
top 42.3%
This planet
2.73R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-125 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.73 | 11.21 |
| Mass (M⊕) | 1.00 | 9.50 | 317.83 |
| Density (g/cm³) | 5.51 | 2.57 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.28 | 2.53 |
| Insolation (S⊕) | 1.00 | 185.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 9.500 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 52368076
Gaia DR2
Gaia DR2 4698692744355471616
Gaia DR3
Gaia DR3 4698692748651744128
System
TOI-125
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.65 Earth days (1.3% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0519 AU.
Transit Fingerprint
Depth
0.087 %
Duration
2.962 h
Impact parameter b
0.270
Rp / R★
0.029500
Transit midpoint (BJD)
2,458,355.3553
Photometric dip
Transit produces a flux drop of 870 ppm lasting ≈ 2.96 h.
Extended Orbital Architecture
Planet / star radius ratio
0.029500
Semi-major axis / stellar radius
13.160
Impact parameter (b)
0.270
RV semi-amplitude (K)
4.110 m/s
Transit mid-time (BJD)
2,458,355.3553
Long. of periastron (ω)
-37.00°
Angular separation (arcsec)
0.46700
Eq. Temperature
1,037K
(764 °C)
Insolation (S⊕)
185.00
Earth = 1.00
Earth Similarity (ESI)
0.238
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the 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
Quinn et al. 2019Instrument
TESS CCD Array
Publication
2019-11
Observation locale
Space
Discovery cohort
Planets confirmed in 2019 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-125
Spectral Class
K-type orange
Effective Temperature
5,320 K — cooler than the Sun (5,778 K)
Estimated Age
6.80 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.848 R☉
Stellar Mass
0.859 M☉
Metallicity [Fe/H]
-0.02
Extended Stellar Properties
Surface gravity (log g)
4.516 dex
Stellar density
1.990 g/cm³
Systemic radial velocity
11.06 km/s
Rotational v·sin i
1.00 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 14 bands
Astrometric Data
Parallax
8.975 mas
Total Proper Motion
171.667 mas/yr
PM Right Ascension
-119.80 mas/yr
PM Declination
-122.95 mas/yr
Galactic Cartesian (pc)
x = 0.363 · y = 0.158 · z = -0.918
Equatorial (J2000)
RA 23.59343° · Dec -66.67635°
Galactic ℓ, b
296.358° · -49.900°
Ecliptic λ, β
328.779° · -64.896°
HTM-20 index
-852704894
Similar Worlds
K2-266 e
Sub-Neptune · K-type orange
Radius 2.73 R⊕ · 253.0 ly
Kepler-436 b
Sub-Neptune · K-type orange
Radius 2.73 R⊕ · 1,920.6 ly
Kepler-551 b
Sub-Neptune · K-type orange
Radius 2.73 R⊕ · 1,014.9 ly
Kepler-2000 b
Sub-Neptune · K-type orange
Radius 2.73 R⊕ · 1,045.6 ly
Kepler-1058 b
Sub-Neptune · K-type orange
Radius 2.72 R⊕ · 1,604.7 ly
K2-250 b
Sub-Neptune · K-type orange
Radius 2.71 R⊕ · 1,352.6 ly