Key parameters at a glance
- A radius of 6.96 Earth radii
- A mass of 46.17 Earth masses
- Surface gravity around 0.95 g
- An orbital period of 4.532 days
- Semi-major axis 0.0539 AU
- Equilibrium temperature 895 K (622 °C)
- Distance from Earth 313.87 light-years
- Earth Similarity Index 0.186
- Travel time at Voyager 1 speed 5,535,138 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-181 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#207of 574
top 35.9%
This planet
6.96R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | TOI-181 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 6.96 | 11.21 |
| Mass (M⊕) | 1.00 | 46.17 | 317.83 |
| Density (g/cm³) | 5.51 | 0.76 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.95 | 2.53 |
| Insolation (S⊕) | 1.00 | 102.43 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 46.169 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 46.149 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 76923707
Gaia DR2
Gaia DR2 6552346035980010624
Gaia DR3
Gaia DR3 6552346035980010624
System
TOI-181
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.53 Earth days (1.2% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0539 AU.
Transit Fingerprint
Depth
0.730 %
Duration
1.990 h
Impact parameter b
0.535
Rp / R★
0.085400
Transit midpoint (BJD)
2,458,358.1200
Photometric dip
Transit produces a flux drop of 7,300 ppm lasting ≈ 1.99 h.
Extended Orbital Architecture
Planet / star radius ratio
0.085400
Semi-major axis / stellar radius
15.564
Impact parameter (b)
0.535
RV semi-amplitude (K)
20.561 m/s
Transit mid-time (BJD)
2,458,358.1200
Long. of periastron (ω)
-96.91°
Angular separation (arcsec)
0.56000
Eq. Temperature
895K
(622 °C)
Insolation (S⊕)
102.43
Earth = 1.00
Earth Similarity (ESI)
0.186
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
Mistry et al. 2023Instrument
TESS CCD Array
Publication
2023-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-181
Spectral Class
K-type orange
Effective Temperature
4,994 K — cooler than the Sun (5,778 K)
Estimated Age
5.40 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.745 R☉
Stellar Mass
0.822 M☉
Metallicity [Fe/H]
0.27
Extended Stellar Properties
Surface gravity (log g)
4.608 dex
Stellar density
2.800 g/cm³
Rotational v·sin i
2.28 km/s
Metallicity ratio
[M/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
10.363 mas
Total Proper Motion
111.394 mas/yr
PM Right Ascension
111.36 mas/yr
PM Declination
-2.59 mas/yr
Galactic Cartesian (pc)
x = 0.817 · y = -0.112 · z = -0.566
Equatorial (J2000)
RA 352.17254° · Dec -34.49141°
Galactic ℓ, b
5.305° · -70.814°
Ecliptic λ, β
338.096° · -28.353°
HTM-20 index
1078775704
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