Key parameters at a glance
- A radius of 9.75 Earth radii
- A mass of 112.00 Earth masses
- Surface gravity around 1.18 g
- An orbital period of 8.798 days
- Semi-major axis 0.0712 AU
- Equilibrium temperature 528 K (255 °C)
- Distance from Earth 608.48 light-years
- Earth Similarity Index 0.279
- Travel time at Voyager 1 speed 10,730,600 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-5573 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#22of 574
top 3.7%
This planet
9.75R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | TOI-5573 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 9.75 | 11.21 |
| Mass (M⊕) | 1.00 | 112.00 | 317.83 |
| Density (g/cm³) | 5.51 | 0.66 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.18 | 2.53 |
| Insolation (S⊕) | 1.00 | 12.92 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 112.000 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 459762279
Gaia DR2
Gaia DR2 1023967108705998208
Gaia DR3
Gaia DR3 1023967108706495360
System
TOI-5573
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 8.80 Earth days (2.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0712 AU.
Transit Fingerprint
Depth
2.309 %
Duration
2.760 h
Impact parameter b
0.430
Rp / R★
0.150000
Transit midpoint (BJD)
2,459,600.4508
Photometric dip
Transit produces a flux drop of 23,090 ppm lasting ≈ 2.76 h.
Extended Orbital Architecture
Planet / star radius ratio
0.150000
Semi-major axis / stellar radius
25.740
Impact parameter (b)
0.430
RV semi-amplitude (K)
47.900 m/s
Transit mid-time (BJD)
2,459,600.4508
Long. of periastron (ω)
32.80°
Angular separation (arcsec)
0.38200
Eq. Temperature
528K
(255 °C)
Insolation (S⊕)
12.92
Earth = 1.00
Earth Similarity (ESI)
0.279
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
Fernandes et al. 2025Instrument
TESS CCD Array
Publication
2025-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-5573
Spectral Class
K-type orange
Effective Temperature
3,790 K — cooler than the Sun (5,778 K)
Estimated Age
9.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.594 R☉
Stellar Mass
0.619 M☉
Metallicity [Fe/H]
0.42
Extended Stellar Properties
Surface gravity (log g)
4.680 dex
Stellar density
4.080 g/cm³
Rotational v·sin i
2.00 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
5.332 mas
Total Proper Motion
57.096 mas/yr
PM Right Ascension
-3.63 mas/yr
PM Declination
-56.98 mas/yr
Galactic Cartesian (pc)
x = -0.412 · y = 0.392 · z = 0.822
Equatorial (J2000)
RA 136.42600° · Dec 55.30713°
Galactic ℓ, b
161.808° · 40.919°
Ecliptic λ, β
120.969° · 36.749°
HTM-20 index
157706843
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