Key parameters at a glance
- A radius of 9.55 Earth radii
- A mass of 55.30 Earth masses
- Surface gravity around 0.61 g
- An orbital period of 3.685 days
- Semi-major axis 0.0496 AU
- Equilibrium temperature 1,526 K (1253 °C)
- Distance from Earth 778.76 light-years
- Earth Similarity Index 0.082
- Travel time at Voyager 1 speed 13,733,364 years
TOI-954 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#40of 574
top 6.8%
This planet
9.55R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | TOI-954 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 9.55 | 11.21 |
| Mass (M⊕) | 1.00 | 55.30 | 317.83 |
| Density (g/cm³) | 5.51 | 0.35 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.61 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,393.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 55.302 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 55.302 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 55.568 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
TIC
TIC 44792534
Gaia DR2
Gaia DR2 4890874702443960832
Gaia DR3
Gaia DR3 4890874702443960832
System
TOI-954
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.68 Earth days (1.0% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0496 AU.
Transit Fingerprint
Depth
0.207 %
Duration
5.090 h
Impact parameter b
0.560
Rp / R★
0.046200
Transit midpoint (BJD)
2,458,411.9065
Photometric dip
Transit produces a flux drop of 2,070 ppm lasting ≈ 5.09 h.
Extended Orbital Architecture
Planet / star radius ratio
0.046200
Semi-major axis / stellar radius
5.630
Impact parameter (b)
0.560
RV semi-amplitude (K)
20.700 m/s
Transit mid-time (BJD)
2,458,411.9065
Long. of periastron (ω)
276.00°
Angular separation (arcsec)
0.20800
Eq. Temperature
1,526K
(1253 °C)
Insolation (S⊕)
1,393.00
Earth = 1.00
Earth Similarity (ESI)
0.082
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
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
Sha et al. 2021Instrument
TESS CCD Array
Publication
2021-02
Observation locale
Space
Discovery cohort
Planets confirmed in 2020 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-954
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,710 K — cooler than the Sun (5,778 K)
Estimated Age
6.14 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.892 R☉
Stellar Mass
1.201 M☉
Metallicity [Fe/H]
0.22
Extended Stellar Properties
Surface gravity (log g)
3.962 dex
Stellar density
0.249 g/cm³
Systemic radial velocity
-6.89 km/s
Rotational v·sin i
5.60 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
4.160 mas
Total Proper Motion
30.183 mas/yr
PM Right Ascension
-5.79 mas/yr
PM Declination
-29.62 mas/yr
Galactic Cartesian (pc)
x = 0.426 · y = 0.798 · z = -0.426
Equatorial (J2000)
RA 61.94106° · Dec -25.20880°
Galactic ℓ, b
221.978° · -46.189°
Ecliptic λ, β
52.916° · -45.102°
HTM-20 index
201557592
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